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1 aqua Journal of Ichthyology and Aquatic Biology Vol. 11 (4), October 2006 Aquapress ISSN

2 aqua - Journal of Ichthyology and Aquatic Biology Managing Editor: Heiko Bleher Via G. Falcone 11, Miradolo Terme (PV), Italy Tel.: /08 Fax: heiko@aquapress-bleher.it Scientific Editor: Friedhelm Krupp Curator of Fishes Senckenberg Research Institute and Natural History Museum Senckenberganlage Frankfurt am Main, Germany Tel: Fax: f.krupp@senckenberg.de Editorial Board: Gerald R. Allen Department of Aquatic Zoology, Western Australian Museum, Perth, Australia Nina G. Bogutskaya Zoological Institute of the Russian Academy of Sciences, St. Petersburg, Russia Wilson J. E. M. Costa Laboratório de Ictiologia Geral e Aplicada, Departamento de Zoologia, Universidade Federal do Rio de Janeiro, Brasil Axel Meyer Lehrstuhl für Zoologie und Evolutionsbiologie, Universität Konstanz, Germany Paolo Parenti Department of Enviromental Sciences, University of Milano-Bicocca, Milan, Italy Mário de Pinna Museu de Zoologia da USP, São Paulo, Brazil John E. Randall Bishop Museum, Honolulu, Hawaii, U.S.A. Richard Winterbottom Centre of Biodiversity & Conservation Biology, Royal Ontario Museum, Toronto, Canada Scope aqua is an international journal which publishes original scientific articles in the fields of systematics, taxonomy, biogeography, ethology, ecology, and general biology of fishes. Papers on freshwater, brackish, and marine fishes will be considered. aqua is fully refereed and aims at publishing manuscripts within 2-4 months of acceptance. In view of the importance of color patterns in species identification and animal ethology, authors are encouraged to submit color illustrations in addition to descriptions of coloration. It is our aim to provide the international scientific community with an efficiently published journal meeting high scientific and technical standards. Call for papers The editors welcome the submission of original manuscripts which should be sent in digital format to the scientific editor. Full length research papers and short notes will be considered for publication. There are no page charges and color illustrations will be published free of charge. Authors will receive one free copy of the issue in which their paper is published and an e-print in PDF format. Subscription Notice At least one volume (4 issues) of aqua is being published per year, each issue comprising 48 pages (including cover). The subscription rate (for one volume = 4 issues) is from volume 12 on: Personal subscription: Euro 75,00 (incl. priority mail); Institutional subscription: Euro 140,00 (incl. priority mail). Subscription enquires should be sent to the publisher at the address given below or by to: aqua@aquapress-bleher.it aqua binder Binders for Volumes of aqua are available at cost price Euro 12,50 (US$ 15.00) plus postage Euro 8,00 (US$ 10.00). Notice: aqua Volumes 1(1)-5(4) = 1st. binder; Volumes 6(1)-9(4) = 2nd. binder; Volumes 10(1)-13(4) = 3rd. binder. Special Publication Since 2003 Aquapress publishes a series of Special Publications, which are produced at irregular intervals. All Special Publications have about 100 or more pages and are available separately from regular issues of aqua. Enquiries about subscriptions and prices should be sent to the publisher at the address given here above or by to: aqua@aquapress-bleher.it ISSN Publisher: Aquapress, Redazione aqua, I Miradolo Terme (Pavia), Italy Printer: SATE s.r.l. (Bergamo), Italy Copyediting and layout: Rossella Bulla 2006 aqua, Journal of Ichthyology and Aquatic Biology

3 aqua, Journal of Ichthyology and Aquatic Biology Relationships and taxonomy of the killifish genus Rivulus (Cyprinodontiformes: Aplocheiloidei: Rivulidae) from the Brazilian Amazonas river basin, with notes on historical ecology Wilson J. E. M. Costa Laboratório de Ictiologia Geral e Aplicada, Departamento de Zoologia, Universidade Federal do Rio de Janeiro, Caixa Postal 68049, CEP , Rio de Janeiro, Brasil. wcosta@acd.ufrj.br Received: 08 April 06 Accepted: 15 August 06 Abstract Relationships among species of Rivulus endemic to the Brazilian Amazonas river basin are evaluated through an analysis of morphological characters, including terminal taxa representative of all Rivulus lineages. Based on the present morphological phylogeny and previous molecular analyses, seven subgenera are recognized: Rivulus, Cynodonichthys, Anablepsoides, Benirivulus n. subgen., Laimosemion, Owiyeye n. subgen., and Melanorivulus n. subgen. Benirivulus is diagnosed by a unique colour pattern and includes a single species, R. beniensis, from the rio Madeira drainage; Owiyeye is diagnosed by the absence of dermosphenotic, a derived pattern of frontal squamation, and a colour pattern of the mandibular region, and includes species from the Amazonas and Orinoco river basins; Melanorivulus is diagnosed by an apomorphic morphology of preopercle, and derived colour patterns of male postorbital region and female unpaired fins, and includes species from southern Amazonian tributaries, Paraná-Paraguay river system, and Parnaíba and São Francisco river basins. Eighteen species from the Amazonas river basin of Brazil are recognized as valid: R. urophthalmus, R. taeniatus, R. micropus, R. ornatus, R. beniensis, R. strigatus, and R. dibaphus, which are herein redescribed, and R. atratus, R. romeri, R. kirovskyi, R. uatuman, R. uakti, R. amanapira, R. tecminae, R. modestus, R. zygonectes, R. violaceus, and R. litteratus, described or redescribed recently. Field data indicate that species of different lineages included in the clade comprising Benirivulus, Laimosemion, Owiyeye, and Melanorivulus are found in different kinds of aquatic environments, suggesting a divergent evolution for habitat preference. Resumo As relações de parentesco entre espécies de Rivulus endêmicas da bacia amazônica brasileira são avaliadas através de uma análise de caracteres morfológicos, incluindo táxons terminais representativos de todas as linhagens de Rivulus. Com base na presente filogenia morfológica e em análises moleculares anteriores, sete subgêneros são reconhecidos: Rivulus, Cynodonichthys, Anablepsoides, Benirivulus n. subgen., Laimosemion, Owiyeye n. subgen., e Melanorivulus n. subgen. Benirivulus é diagnosticado por um padrão de colorido exclusivo e inclui uma única espécie, R. beniensis, da drenagem do rio Madeira; Owiyeye é diagnosticado pela ausência de dermosfenótico, um padrão de escamação frontal derivado e um padrão de colorido da região mandibular, e inclui espécies das bacias dos rios Amazonas e Orinoco; Melanorivulus é diagnosticado pela morfologia apomórfica do pré-opérculo e pelos padrões de colorido derivados de região pós-orbital de macho e de nadadeiras ímpares de fêmeas, e inclui espécies dos tributários amazônicos meridionais, do sistema de rios Paraná-Paraguai, e bacias dos rios Paranaíba e São Francisco. Dezoito espécies da bacia do rio Amazonas do Brasil são reconhecidas como válidas: R. urophthalmus, R. taeniatus, R. micropus, R. ornatus, R. beniensis, R. strigatus e R. dibaphus, que são aqui redescritas, e R. atratus, R. romeri, R. kirovskyi, R. uatuman, R. uakti, R. amanapira, R. tecminae, R. modestus, R. zygonectes, R. violaceus e R. litteratus, recentemente descritas ou redescritas. Dados de campo indicam que espécies de distintas linhagens, incluídas no clado que compreende Benirivulus, Laimosemion, Owiyeye e Melanorivulus, são encontradas em tipos deferentes de ambientes aquáticos, sugerindo uma evolução divergente para preferência de habitats. Zusammenfassung Die verwandtschaftlichen Beziehungen der Arten der Gattung Rivulus, die endemisch im Amazonasbecken vorkommen, werden anhand von morphologischen Merkmalen untersucht und die Taxa der verschiedenen Linien innerhalb der Gattung abschließend bewertet. Auf der Grundlage der gegenwärtig bekannten morphologisch begründeten Abstammungsverhältnisse und der vorhandenen genetischen Analysen lassen sich sieben Untergattungen unterscheiden: Rivulus, Cynodonichthys, Anablepsoides, Benirivulus n. subgen., Laimosemion, Owiyeye n. subgen. und Melanorivulus n. subgen. Benirivulus lässt sich durch die einmalige Färbung eindeutig erkennen und umfasst nur eine Art: R. beniensis vom Rio Madeira und seinem Einzugsgebiet. Owiyeye kann am Fehlen des dermosphenotischen Knochens, am sekundären Muster der Frontalbeschuppung und am Farbmuster des Unterkieferbereichs bestimmt werden; zu dieser Untergattung zählen Arten vom Amazonas- und vom Orinocobecken. Melanorivulus wird gekennzeichnet durch: apomorphe (evo- 133 aqua vol. 11 no

4 Killifish genus Rivulus (Rivulidae) from the Brazilian Amazonas river basin lutiv neue) Gestaltung des Präoperculums, abgeleitete Farbmuster der Postorbital-Region bei Männchen und unpaare Flossen bei Weibchen; Arten der südlichen Nebenflüsse des Amazonas, des Paraná-Paraguay-Systems und der Parnaibaund São-Francisco-Flussbecken gehören dazu. Achtzehn Arten des brasilianischen Amazonasbeckens werden als gültig anerkannt: R. urophthalmus, R. taeniatus, R. micropus, R. ornatus, R. beniensis, R. strigatus und R. dibaphus, die hiermit wiederbeschrieben wird, sowie R. atratus, R. romeri, R. kirovskyi, R. uatuman, R. uakti, R. amanapira, R. tecminae, R. modestus, R. zygonectes, R. violaceus und R. litteratus, die in letzter Zeit neu oder wiederbeschrieben wurden. Nach Freilandbeobachtungen kommen die Arten verschiedener Abstammungslinien der Klade mit Benirivulus, Laimosemion, Owiyeye und Melanorivulus in unterschiedlichen aquatischen Lebensräumen vor, sodass von einer divergenten Evolution gemäß dem bevorzugten Habitat auszugehen ist. Résumé Des affinités entre des espèces de Rivulus endémiques du bassin brésilien de l Amazone sont évaluées au moyen d une analyse de caractéristiques morphologiques, incluant des taxons terminaux représentatifs de tous les lignages de Rivulus. Sur base de la phylogénie morphologique actuelle et d analyses moléculaires antérieures, sept sous-genres sont identifiés: Rivulus, Cynodonichthys, Anablepsoides, Benirivulus n. subgen., Laimosemion, Owiyeye n. subgen. et Melanorivulus n. subgen. Benirivulus se distingue par un patron de coloration unique et comprend une seule espèce, R. beniensis, du système du Rio Madeira; Owiyeye est distinct par l absence de dermosphénotique, un patron dérivé d écailles frontales, et un patron de coloration de la région mandibulaire, et inclut des espèces des bassins de l Amazone et de l Orénoque; Melanorivulus se distingue par une morphologie apomorphique du pré opercule, des patrons de colorations dérivés de la région postorbitale du mâle et des nageoires impaires de la femelle et compte des espèces des tributaires sud de l Amazone, du système du Paraná-Paraguay, du bassin du Paranaíba et du São Francisco. Dix-huit espèces du bassin brésilien de l Amazone sont reconnues: R. urophthalmus, R. taeniatus, R. micropus, R. ornatus, R. beniensis, R. strigatus et R. dibaphus, qui sont redécrits ici, et R. atratus, R. romeri, R. kirovskyi, R. uatuman, R. uakti, R. amanapira, R. tecminae, R. modestus, R. zygonectes, R. violaceus et R. litteratus, décrits ou redécrits récemment. Des donnés de terrain révèlent que des espèces de différents lignages faisant partie du clade comprenant Benirivulus, Laimosemion, Owiyeye et Melanorivulus se trouvent dans diverses sortes d environnements aquatiques, suggérant une évolution divergente en matière de choix d habitat. Sommario I rapporti di parentela tra le specie del genere Rivulus endemiche della regione amazzonica del Brasile sono stati valutati con un analisi dei caratteri morfologici, includendo taxa rappresentativi di tutte linee evolutive di Rivulus. Sulla base di questa analisi filogenetica e di precedenti filogenesi molecolari sono riconosciuti sette sottogeneri: Rivulus, Cynodonichthys, Anablepsoides, Benirivulus n. subgen., Laimosemion, Owiyeye n. subgen. e Melanorivulus n. subgen. Benirivulus è diagnosticato dalla singolare colorazione e comprende una sola specie, R. beniensis, presente nel bacino idrografico del rio Madeira; Owiyeye è diagnosticato per l assenza del dermosfenotico, per un modello derivato di disposizione delle squame frontali e per la colorazione della regione mandibolare, e include specie dei bacini del Rio delle Amazzoni e dell Orinoco; Melanorivulus è diagnosticato da una morfologia apomorfica del preopercolo e una colorazione derivata della regione postorbitale del maschio e delle pinne impari delle femmine, e include specie diffuse nei tributari meridionali del Rio delle Amazzoni, e nei bacici del Paraná- Paraguay, del Parnaíba e del São Francisco. Diciotto specie sono riconosciute come valide nel bacino amazzonico brasiliano: R. urophthalmus, R. taeniatus, R. micropus, R. ornatus, R. beniensis, R. strigatus e R. dibaphus, che sono qui ridescritte, e R. atratus, R. romeri, R. kirovskyi, R. uatuman, R. uakti, R. amanapira, R. tecminae, R. modestus, R. zygonectes, R. violaceus e R. litteratus, che sono state descritte o ridescritte recentemente. Dati di campionamento indicano che le specie delle diverse linee evolutive incluse nell unità cladistica comprendente Benirivulus, Laimosemion, Owiyeye e Melanorivulus sono diffuse in varie tipologie di ambiente acquatico, suggerendo un evoluzione divergente nella preferenza dell habitat. Introduction Rivulus Poey, 1860 is the most geographically widespread and diversified genus of Neotropical aplocheiloid killifishes (e.g. Costa 2003a). It is also the most taxonomically problematic genus of Neotropical aplocheiloids, in spite of recent efforts to clarify the taxonomic status of included species, among which many are still poorly defined. Taxonomic problems are due to: great number of included species (over 100 nominal species) in a wide geographic range (from Mexico, about 20 N, to Argentina, about 30 S, including Caribbean islands), making it difficult to develop taxonomic studies encompassing comparative material from all regions; brief descriptions, often including only a few characters insufficient to diagnose taxa; bad preservation of type specimens; equivocal synonymies (e.g. Garman 1895); and, unknown data on colour patterns of live specimens in older descriptions. Rivulus was erected to include a single species from Cuba, R. cylindraceus Poey, 1860 (Poey 1860). Since then, over 120 nominal species were incorporated into Rivulus, some subgenera were described, and some species groups were diagnosed (e.g. Hoedeman 1959; Huber 1992; Costa 1995a, 2003a). Some studies have been directed to the taxonomy of Rivulus in some regularly and recently explored zoogeographical areas, including: Central America (e.g. Bussing 1980; Etzel & Berkenkamp 1992; aqua vol. 11 no

5 Wilson J. E. M. Costa Berkenkamp & Etzel a, 1993b, 1995, 1997, 1999), Guianas (Hoedeman 1959; Huber 1979, 1991; Vermeulen & Isbrücker 2000), río Orinoco basin (Thomerson et al. 1991a, 1991b, 1992; Lasso et al. 1992; Thomerson & Taphorn 1992, 1993), Peruvian Amazon (e.g. Fels & Huber 1985; Fels & de Rham 1982), and central and south-eastern Brazil (e.g. Seegers 1984; Costa 1989, 1991, 1995a, 2003c, 2004g, 2005a; Costa & Brasil 1991). However, species of Rivulus endemic to the Brazilian Amazon have received little attention, except for recent descriptions of new species from the rio Negro drainage and near localities (e.g. Costa 2003b, 2004c, 2004d, 2004e). Among species of Rivulus from the Brazilian Amazon are some of the oldest species names presently assigned to the genus, therefore making them important keys in solving taxonomic problems. The only genus today considered to be a synonym of Rivulus is Cynodonichthys Meek, 1904, which was described to include C. tenuis Meek from Mexico (Meek 1904). Cynodonichthys has been placed in the synonymy of Rivulus since Regan (1907). Vomerivulus Fowler, 1944 was proposed as a new monotypic subgenus of Rivulus based on the possession of vomerine teeth in its type species, R. leucurus Fowler, 1944, from the río Juradó, Colombia (Fowler 1944). However, possession of vomerine teeth is a plesiomorphic condition in rivulids, occurring in most aplocheiloids, including R. cylindraceus, the type species of Rivulus (e.g. Costa 1998a, 1998b). Hoedeman (1959, 1961), based on combinations of morphological features such as presence of caudal spot, details of colour patterns, maximum adult size, frontal squamation pattern, and number of longitudinal scales, divided Rivulus into species groups. Huber (1992) adopted this classification, recognizing a total of 18 assemblages (i.e., superspecies), besides describing a new monotypic subgenus, Anablepsoides Huber, 1992, for R. atratus Garman, Subsequently, two Huber s superspecies were formally recognized as new subgenera, Oditichthys Huber, 1999 and Laimosemion Huber, 1999 (Huber 1999). Some species groups have been consistently supported both by osteological (Costa 1998a) and molecular data (Murphy & Collier 1996, Murphy et al. 1999, Hrbek & Larson 1999, Hrbek et al. 2004). Since the first taxonomic revision of the species grouped into the cyprinodontiform assemblage today known as the Rivulidae by Garman (1895), until recent years (Parenti 1981), Rivulus was defined by a combination of plesiomorphic morphological features. In other words, Rivulus was diagnosed by the absence of the distinctive features (i.e., apomorphies) that diagnose the other rivulid genera (e.g. long fins in Pterolebias Garman, 1895, vs. short fins in Rivulus; numerous dorsal- and analfin rays in Cynolebias Steindachner, 1876, vs. few rays in Rivulus) (Garman 1895, Regan 1912, Myers 1927). In addition, Rivulus contained species living in perennial aquatic biotopes, whereas the remaining rivulids comprised species inhabiting seasonal pools. Weitzman & Wourms (1967) suggested that rivulids were derived from a Rivulus-like ancestor. Parenti (1981), based on morphological characters, provided the first phylogenetic analysis of rivulids, in which Rivulus was considered a paraphyletic group with their nominal species included at least in two basal rivulid lineages. Among the five nominal species of Rivulus examined in Parenti s analysis, R. stellifer Thomerson & Turner, 1973 (transferred to Rachovia Myers by Costa 1998a) and R. hartii (Boulenger, 1890) were placed in an assemblage termed Rivulus, that would be more closely related to all other rivulid genera (e.g. Cynolebias; Pterolebias; Trigonectes Myers, 1925) than to Rivulus, which would include the type species R. cylindraceus, and R. marmoratus Poey, 1880 (transferred to Kryptolebias Costa, 2004 by Costa 2004a) and R. tenuis (Meek, 1904), among the species analysed in this study. Consequently, Rivulus was considered to be the sister group to a clade including Rivulus and all other rivulids, which was diagnosed by an apomorphic cartilaginous interhyal (vs. ossified in Rivulus) and a derived number of pelvic-fin rays (seven in Rivulus and the remaining rivulids, vs. six in Rivulus). However, Parenti (1981) did not find synapomorphies corroborating the monophyly of Rivulus or of Rivulus. Costa (1990), in a phylogenetic analysis based on morphological and behavioural traits, confirmed the presence of an ossified interhyal in some species then placed in Rivulus, but demonstrated that the number of seven pelvic-fin rays is not informative to define a rivulid clade. Rivulus was considered to be a monophyletic group based on the morphology of the shoulder girdle and the neural prezygapophyses of caudal vertebrae. A similar general phylogenetic hypothesis among rivulid lineages was obtained by Murphy & Collier (1997) using mitochondrial genes of seven rivulid species, but monophyly of Rivulus was not properly tested since only two species of Rivulus were included in the analysis. 135 aqua vol. 11 no

6 Killifish genus Rivulus (Rivulidae) from the Brazilian Amazonas river basin Costa (1998a), in a subsequent phylogenetic study of rivulids, including new taxa and re-evaluating previously described morphological and behavioural characters, noted that, in fact, R. cylindraceus, the type species of Rivulus, not available in the previous study, has a cartilaginous interhyal. Among the new characters analysed, Costa (1998a) found that species of Rivulus with an ossified interhyal, i.e. R. brasiliensis (Valenciennes, 1821), R. caudomarginatus Seegers, 1984, and R. ocellatus Hensel, 1868, all later transferred to Kryptolebias by Costa (2004a) also exhibit other putative plesiomorphic conditions, and thus monophyly of Rivulus was weakly supported. Subsequent molecular analyses (Murphy et al. 1999, Hrbek & Larson 1999, Hrbek et al. 2004) indicated Rivulus as a paraphyletic group, with different assemblages as successive sister groups to a clade including annual fish genera. Costa (2004a) described Kryptolebias to include species previously placed in Rivulus with an osseous interhyal, among other morphological features. Kryptolebias was considered to be the sister group to a clade including Rivulus and all other rivulids (Costa 2004a, 2004b, 2004c), a hypothesis supported by molecular data (Vermeulen & Hrbek 2005). Since the description of Kryptolebias and the consequent transference of some species of Rivulus to Kryptolebias, a re-evaluation of the generic placement of species maintained in Rivulus became necessary, as well as a reassessment of morphological characters employed to define subgroups of Rivulus. The objectives of the present study are: to test hypotheses of relationships among species of Rivulus from the Brazilian Amazon to other rivulids, based on morphological characters discussed and illustrated in previous studies (e.g. Costa 1990, 1998, 2004, 2005b); to diagnose and to update data on the taxonomy and distribution of species of Rivulus from the Brazilian Amazonas basin, providing redescriptions of poorly known species; to re-evaluate morphological diagnoses for nominal subgenera and to purpose a new classification in order to formally accommodate hypotheses derived from recent phylogenetic studies. Material and methods Material pertinent to the taxonomic study on Rivulus from the Brazilian Amazonas river basin is listed in the taxonomical accounts below. Data on material is given in the following order: catalogue number, number of specimens; country: major political division: locality; collectors, and date of collection. Acronyms for institutions are: ANSP, Academy of Natural Sciences, Philadelphia; BMNH, The Natural History Museum, London; CAS, California Academy of Sciences, San Francisco; CBF, Collección Boliviana de Fauna, Museo Nacional de Historia Natural, La Paz; FMNH, Field Museum of Natural History, Chicago; INPA, Instituto Nacional de Pesquisas da Amazônia, Manaus; MCNG, Museo de Ciencias Naturales de la Universidad Nacional Experimental de los Llanos Occidentales, Guanare; MCP, Museu de Ciências e Tecnologia da Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre; MCZ, Museum of Comparative Zoology, Cambridge; MHNC, Museo Nacional de Historia Natural, La Havana; MNRJ, Museu Nacional, Universidade Federal do Rio de Janeiro, Rio de Janeiro; MZUSP, Museu de Zoologia, Universidade de São Paulo, São Paulo; NMW, Naturhistorisches Museum Wien, Vienna; UFPB, Universidade Federal da Paraíba, João Pessoa; UFRJ, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro; UMMZ, University of Michigan, Museum of Zoology, Ann Arbor; UNT, Universidade Federal do Tocantins, Porto Nacional; USNM, National Museum of Natural History (former United States National Museum), Smithsonian Institution, Washington; ZFMK, Zoologisches Farschungsinstitut und Museum Alexander Koenig, Bonn; and, ZUEC, Departamento de Zoologia da Universidade Estadual de Campinas, Campinas. Geographic entities are presented by their regional names (e.g. rio or río, igarapé, lago), which are not capitalized following Portuguese and Spanish grammars; this practice is important to avoid English style and generalizations when translating South American localities, which become data inaccurate and may incur errors (see also Menezes & Weitzman 1990, and Reis 1997 for further justification for this widely employed practice). EPA, that appears as collectors of some material, means Expedição Permanente da Amazônia, a cooperative project between MZUSP, INPA and Museu Paraense Emilío Goeldi, Belém; NEAMB means Núcleo de Estudos Ambientais da Universidade Federal do Tocantins. The remaining material of Aplocheiloidei taxa examined in the present study is listed in the Appendix 1. Measurements and counts follow Costa (1995b). Measurements are presented as percentages of standard length (SL), except for those related to head morphology, expressed as percentages of head length. Fin-ray counts include all elements. Number of vertebrae, gill rakers, and caudal-fin rays were aqua vol. 11 no

7 Wilson J. E. M. Costa recorded only from cleared and stained specimens. The compound caudal centrum was counted as a single element. Osteological preparations were made according to Taylor & Van Dyke (1985). Terminology for frontal squamation (i.e. A-H) follows Hoedeman (1958); determination of frontal squamation patterns (i.e. D, E, F) is according to Hoedeman (1958) (i.e. frontal scale with all margins free), except S-pattern (i.e. a scale just posterior to snout with all margins free) which is according to Huber (1992). Terminology for cephalic neuromast series follows Costa (2001). The phylogenetic analysis is according to the cladistic methodology applied to morphological characters (e.g. Kitching et al. 1998, Wiens 2000). Terminal taxa were species of Rivulus occurring in the Brazilian Amazonas basin, species of Rivulus representing all main lineages from all zoogeographic regions inserted in the geographic area of the genus, and species of rivulid genera representing lineages closely related to Rivulus according to recent phylogenetic studies (Costa 1998a, Murphy et al. 1999, Hrbek & Larson 1999): Aphyolebias boticarioi Costa, 2004, Gnatholebias hoignei (Thomerson, 1974), Micromoema xiphophora (Thomerson & Taphorn, 1992), Moema apurinan Costa, 2004, Neofundulus paraguayensis (Eigenmann & Kennedy, 1903), Pituna compacta (Myers, 1927), Rachovia maculipinnis (Radda, 1964), Rachovia stellifer, Renova oscari Thomerson & Taphorn, 1995, and Trigonectes rubromarginatus Costa, Four levels of outgroups were included: Prorivulus auriferus Costa, Lima & Suzart, 2004, and Kryptolebias brasiliensis, representing the successive most basal lineages of the Rivulidae (Costa 2004a, 2004c); Scriptaphyosemion guignardi (Romand, 1981) of the Nothobranchidae, the sister group of Rivulidae (Murphy & Collier 1997, Costa 2004a); and, Aplocheilus panchax (Hamilton-Buchanan, 1822) of the Aplocheilidae, the sister group of Nothobranchidae plus Rivulidae (Murphy & Collier 1997, Costa 2004a). Characters were obtained from previous phylogenetic studies (e.g. Parenti 1981; Costa 1990, 1998a, 2005b).Character states of multi-state characters were treated as ordered whenever possible. Boundaries between states of quantitative characters were taken from Costa (2005b), which were determined to accommodate the best estimate of range observed for each terminal species included in that category (i.e. character state). All characters and character states used in the phylogenetic analysis are listed and coded in the Appendix 2 and are organized in the data matrix of Appendix 3. Most parsimonious cladograms, consistency indices (CI) and retention indices (RI) were obtained using the algorithm mhennig*;bb* of the program Hennig86 (Farris 1988). TreeGardener (Ramos 1996) was used for optimisation of character state changes in the strict consensus tree of most parsimonious cladograms, using ACCTRAN. Bootstrap analysis (Felsenstein 1985) was used to establish nodal support through the simple heuristic algorithm of PAUP 4.0 (Swoford 1998) with 1000 replicates. Results Phylogenetic analysis The phylogenetic analysis is based on a re-examination of previously reported, discussed and illustrated morphological characters (e.g. Parenti 1981; Costa 1990, 1998a, 2005b), which are listed in the Appendix 2. Their distribution among taxa examined appears in the data matrix (Appendix 3). Six most parsimonious cladograms were found (tree length = 364, CI = 0.42, RI = 0.72). They differ only in the position of R. igneus, (i.e., as sister to R. hartii or to R. amphoreus Huber, 1979), and R. uatuman Costa, 2004 (i.e., as sister to R. romeri Costa, 2003 or to R. kirovskyi Costa, 2004). The strict consensus tree (three length = 367, CI = 0.41, RI = 0.71) is illustrated in Fig. 1. Taxonomic accounts Rivulus is here formally divided into seven subgenera, which are supported both by morphological (the present analysis) and molecular data (e.g. Murphy et al. 1999, Hrbek & Larson 1999; see discussion below). Subgenera of Rivulus and species occurring in the Brazilian Amazonas basin are listed and diagnosed below. Diagnoses of subgenera are synapomorphies obtained from the above phylogenetic analysis; numbers in parentheses refer to characters states listed in Appendix 2. Rivulus Poey, 1860 Rivulus Poey, 1860: 299 (type species: Rivulus cylindraceus Poey; type by monotypy). Subgenus Rivulus Poey, 1860 Rivulus Poey, 1860: 299 (type species: Rivulus cylindraceus Poey; type by monotypy). 137 aqua vol. 11 no

8 Killifish genus Rivulus (Rivulidae) from the Brazilian Amazonas river basin Fig. 1. Strict consensus of six equally parsimonious shortest phylogenies among 47 species of the Rivulidae (L = 367, CI = 0.41, RI = 0.71). Numbers above branches are bootstrap values. aqua vol. 11 no

9 Wilson J. E. M. Costa Distinguished from all other congeners by the possession of the following apomorphic features: hypurals completely fused to form a single plate (45.3), about 60% of the anterior portion of the caudal fin covered by scales (82.2), four neuromasts on the anterior supraorbital series (85.1), and a dark metallic blue humeral blotch in male. Included species R. cylindraceus Poey, 1860, R. insulaepinorum De La Cruz & Dubitsky, 1976 and R. roloffi Roloff, Rivers basins of Cuba and Republica Dominicana. Subgenus Cynodonichthys Meek, 1904 Cynodonichthys Meek, 1904: 98 (type species: Cynodonichthys tenuis Meek; type by original designation). Vomerivulus Fowler, 1944: 244 (type species: Rivulus leucurus Fowler; type by original designation). Oditichthys Huber, 1999: 49 (type species: Rivulus igneus Huber; type by original designation). Tentatively diagnosed by the presence of yellow stripes on dorsal and ventral margins of caudal fin in male (101.1, 102.1), a condition inconspicuous or absent in some members of Cynodonichthys (i.e. reversals), but also exhibited by some species of Owiyeye (i.e. homoplasies). Included species Rivulus amphoreus Huber, 1979, R. bahianus Huber, 1990, R. birkhahni Berkenkamp & Etzel, 1992, R. boehlkei Huber & Fels, 1985, R. brunneus Meek & Hildebrand, 1913, R. christinae Huber, 1992, R. chucunaque Breder, 1925, R. cryptocallus Seegers & Huber, 1981, R. deltaphilus Seegers, 1983, R. depressus Costa, 1991, R. derhami Fels & Huber, 1985, R. elegans Steindachner, 1880, R. elongatus Fels & de Rham, 1981, R. erberi Berkenkamp, 1989, R. frommi Berkenkamp & Etzel, 1993, R. fuscolineatus Bussing, 1980, R. glaucus Bussing, 1980, R. haraldsiolii Berkenkamp, 1984, R. hartii (Boulenger, 1890), R. hildebrandi Myers, 1927, R. holmiae Eigenmann, 1909, R. igneus Huber, 1991, R. immaculatus Thomerson, Nico & Taphorn, 1991, R. intermittens Fels & de Rham, 1981, R. iridescens Fels & de Rham, 1981, R. isthmensis Garman, 1895, R. janeiroensis Costa, 1991, R. jucundus Huber, 1992, R. kuelpmanni Berkenkamp & Etzel, 1993, R. lanceolatus Eigenmann, 1909, R. leucurus Fowler, 1944, R. limoncochae Hoedeman, 1962, R. luelingi Seegers, 1984, R. lungi Berkenkamp, 1984, R. magdalenae Eigenmann & Henn, 1916, R. mazaruni Myers, 1924, R. micropus (Steindachner), 1863, R. monikae Berkenkamp & Etzel, 1995, R. monticola Staeck & Schindler, 1997, R. montium Hildebrand, 1938, R. nudiventris Costa & Brasil, 1991, R. ophiomimus Huber, 1992, R. pacificus Huber, 1992, R. peruanus (Regan, 1903), R. rubripunctatus Bussing, 1980, R. rubrolineatus Fels & de Rham, 1981, R. santensis Köhler, 1906, R. siegfriedi Bussing, 1980, R. simplicis Costa, 2004, R. speciosus Fels & de Rham, 1981, R. stagnatus Eigenmann, 1909, R. sucubti Breder, 1925, R. taeniatus Fowler, 1945, R. tenuis (Meek, 1904), R. tessellatus Huber, 1992, R. uroflammeus Bussing, 1980, R. urophthalmus Günther, 1866, R. villwocki Berkenkamp & Etzel, 2002, R. waimacui Eigenmann, 1909, R. wassmanni Berkenkamp & Etzel, 1999, R. weberi Huber, 1992, and R. xanthonotus Ahl, River basins of Mesoamerica (between Mexico and Panama, and southern Caribbean islands), and northern (Colombia, Venezuela, Guianas, Peru, Ecuador, Bolivia and northern Brazil) and eastern South America (coastal plains of south, south-eastern and north-eastern Brazil). Rivulus urophthalmus Günther, 1866 (Figs. 2-9; Table I) Rivulus urophthalmus Günther, 1866: 327 (type locality: Para [Belém, formerly often known as Pará, northern Brazil]; lectotype: BMNH , designated by Huber 1991:67; photograph of lectotype in Huber 1991: 72, fig. 7). Rivulus poey Steindachner, 1876: 165 (type locality: canals in the city of Para [now Belém]; types unknown; neotype: UFRJ 6282, male, 34.9 mm SL; creek at 15 de agosto street, Icoaraci, Belém; collected by A. Sarraf & M. Mourão Jr., 24 Jul [herein designated]). Rivulus urophthalmus var. aurata Schreitmüller, 1928: 88 (Maharankao [correctly Maranhão], Brazil; type: not designated). 139 aqua vol. 11 no

10 Killifish genus Rivulus (Rivulidae) from the Brazilian Amazonas river basin Material examined Brazil: Estado do Pará: UFRJ 6247, 18; stream in praia de Ariramba, ilha do Mosqueiro, Belém, S W; W. J. E. M. Costa, R. Paiva & D. Ramos, 21 Jun UFRJ 6248, 11; stream in ilha do Mosqueiro, Belém, S W; W. J. E. M. Costa, R. Paiva & D. Ramos, 21 Jun UFRJ 6254, 8; UFRJ 6261, 3; stream crossing the road PA-391, ilha do Mosqueiro, Belém, S W; W. J. E. M. Costa, R. Paiva & D. Ramos, 21 Jun UFRJ 6255, 11; creek near the road PA-124, near Santa Luzia, S W; W. J. E. M. Costa, R. Paiva & D. Ramos, 19 Jun UFRJ 6256, 5; pools near stream near the road PA-446, Primavera, S W; W.J.E.M. Costa, R. Paiva & D. Ramos, 18 Jun UFRJ 6257, 9; swamp at Quatipuru, S W; W. J. E. M. Costa, R. Paiva & D. Ramos, 18 Jun UFRJ 6258, 15; stream near the road PA-124, near Pindorama, Salinópolis, S W; W. J. E. M. Costa, R. Paiva & D. Ramos, 18 Jun UFRJ 6259, 4; UFRJ 6290, 34; stream at forest edge, road PA-446, Primavera, S W; W. J. E. M. Costa, R. Paiva & D. Ramos, 19 Jun UFRJ 4087, 9 (c&s); igarapé Maguary, Belém; A. Sarraf & E. Nogueira, 1 Aug UFRJ 3055, 6 (c&s); Primavera; A. Werner, May UFRJ 4082, 6; campus of Universidade Federal do Pará, Belém; A. Sarraf & M. Mourão Jr., 30 Jul UFRJ 4083, 4; creek at 15 de agosto street, Icoaraci, Belém; A. Sarraf & E. Nogueira, 1 Aug UFRJ 4079, 5; igarapé Maguary, Belém; A. Sarraf & M. Mourão Jr., 24 Jul Estado do Tocantins: UFRJ 5149, 9; floodplains of left bank of rio Tocantins, about 1200 m from the river margin, SSE Sampaio, 5º23 00 S W; G. C. Brasil, 8 Jun UNT 553, 3; rio Brejão, road BR-153, Araguaina; E. Fig. 2. Rivulus urophthalmus, UFRJ 6261, male, 27.1 mm SL (two days after collection); Brazil: Pará: Belém. Photo by W. J. E. M. Costa. Fig. 5. Rivulus urophthalmus, UFRJ 6259, male, 30.1 mm SL (one day after collection); Brazil: Pará: Primavera. Photo by W. J. E. M. Costa. Fig. 3. Rivulus urophthalmus, UFRJ 6261, male, 26.7 mm SL (two days after collection); Brazil: Pará: Belém (same population as Fig. 3, with slightly different colour patterns on the caudal fin). Photo by W. J. E. M. Costa. Fig. 6. Rivulus urophthalmus, UFRJ 6256, male, 26.6 mm SL (one day after collection); Brazil: Pará: Primavera (compare with Fig. 5 to observe different colour patterns on the caudal peduncle). Photo by W. J. E. M. Costa. Fig. 4. Rivulus urophthalmus, UFRJ 6261, female, 30.0 mm SL (two days after collection); Brazil: Pará: Belém. Photo by W. J. E. M. Costa. Fig. 7. Rivulus urophthalmus, UFRJ 6259, female, 33.2 mm SL (one day after collection); Brazil: Pará: Primavera. Photo by W. J. E. M. Costa. aqua vol. 11 no

11 Wilson J. E. M. Costa L. Beerli & L. M. Lima, 22 Nov UNT 554, 5; river at the road BR-153, between Filadelphia and Araguaina; E. L. Beerli, 2 Nov Estado do Amapá: INPA 2244, 26 (3 c&s); stream below cachoeira Santo Antônio, rio Jari drainage; M. Jegu & J. Zuanon, 21 Jun Estado do Maranhão: UFRJ 5152, 16; swamp about 500 m from the right margin of rio Tocantins, S W; G. C. Brasil, 8 Jun UFRJ 6293, 4; Olho d Água das Cunhãs; A. C. De Luca, C. G. C. Wenceslau & M. A. Santos, 7 Jul Distinguished from all other congeners by the combination of the following features: anterior portion of trunk slightly deeper than wide, jaws short, snout blunt, tip of anal fin rounded in male, caudal fin rounded in male, pelvic-fin tip not reaching anus in male, dorsal-fin origin on vertical between base of last 3rd and 4th anal-fin rays, dorsal-fin rays 7-8, anal-fin rays 12-14, frontal squamation E-patterned, frontal scales arranged circularly, canal preopercular short and opened, contact organs absent, longitudinal series of scales 37-40, gill rakers of first branchial arch , red stripes on flank, jaws not distinctively pigmented, and round black spot on dorsal portion of caudal fin in female. Fig. 8. Rivulus urophthalmus, UFRJ 6264, male, 29.5 mm SL (one day after collection); Brazil: Pará: Altamira. Photo by W. J. E. M. Costa. Fig. 9. Rivulus urophthalmus, UFRJ 6264, female, 28.9 mm SL (one day after collection); Brazil: Pará: Altamira. Photo by W. J. E. M. Costa. Fig. 10. Geographic distribution of: Rivulus modestus (dot), R. romeri (inverted triangle), R. taeniatus (stars), R. urophthalmus (triangles), and R. violaceus (lozenges). One symbol may represent more than one collecting site. 141 aqua vol. 11 no

12 Killifish genus Rivulus (Rivulidae) from the Brazilian Amazonas river basin Description Morphometric data appear in Table I. Largest specimen, a female 43.9 mm SL. Dorsal profile gently convex from snout to end of dorsal-fin base, approximately straight on caudal peduncle. Ventral profile slightly convex from lower jaw to end of anal-fin base, about straight on caudal peduncle. Body slender, subcylindrical anteriorly, slightly deeper than wide, to compressed posteriorly. Greatest body depth at vertical just in front to pelvic-fin base. Jaws short, snout blunt. Tip of dorsal and anal fins rounded. Caudal fin rounded. Pectoral fin short and rounded, posterior margin reaching vertical at about 60% of length between pectoral-fin and pelvic-fin bases. Pelvic fin short and elliptical, tip not reaching anus. Pelvic-fin bases medially separated by short interspace. Dorsalfin origin on vertical between base of 3 rd and 4 th last anal-fin rays, and between neural spines of 21 st and 23 rd vertebrae. Anal-fin origin between pleural ribs of 15 th and 17 th vertebrae. Dorsal-fin rays 7-8; analfin rays 12-14; caudal-fin rays 25-28; pectoral-fin rays 13; pelvic-fin rays 6. Scales small, cycloid. Body and head entirely scaled, except anterior ventral surface of head. Body squamation extending over anterior 30 % of caudalfin base; no scales on dorsal- and anal-fin bases. Frontal squamation E-patterned; E-scales not overlapping medially; scales arranged in regular circular pattern around A-scale without exposed margins. Longitudinal series of scales 37-40; transverse series of scales 8; scale rows around caudal peduncle 16. Contact organs absent. Cephalic neuromasts: supraorbital 3 + 3, parietal 1, anterior rostral 1, posterior rostral 1, infraorbital , preorbital 2-3, otic 1, post-otic 2, supratemporal 1, median opercular 1, ventral opercular 2, preopercular 2 + 4, mandibular 4 + 1, lateral mandibular 2-3. Interhyal minute, cartilaginous. Rostral cartilage longer than wide, width about 80% length. Basihyal subtriangular, width about 65% length; basihyal cartilage about 10% basihyal length. Six branchiostegal rays. Second pharyngobranchial teeth 3-4. Gill rakers of first branchial arch Vomerine teeth 5-6. Ventral process of posttemporal short. Total vertebrae Coloration in life: Male: Side of body metallic yellowish green to metallic purplish blue ventrally; eight longitudinal rows of red to reddish brown dots, often in close proximity, forming stripes; usually three, sometimes four or five rows of red dots crossing caudal peduncle and reaching caudal-fin base, remaining rows reaching vertical through anal-fin base; dark chromatophores concentrated on longitudinal zone between flank and dorsum; sometimes dark grey bars on flank anterior to caudal peduncle, when fish exposed to strong sunlight. Dorsum light brown. Venter white. Side of head metallic yellowish green to metallic purplish blue, sometimes dark grey when fish exposed to strong sunlight. Lower jaw light brown. Iris light yellowish to greenish brown. Dorsal fin pale yellow with brown dots on basal portion, often with bright yellow zone. Anal fin yellow, basal portion sometimes blue, often with brown or red dots. Caudal fin pale yellow, often with brown dots and dorsal and ventral bright yellow zones, sometimes dorsal and ventral margins bright orange. Paired fins yellowish hyaline. Female: Side of body light brown, with eight longitudinal rows of reddish brown dots, often in close proximity, forming stripes, alternating with longitudinal rows of pale golden dots; dark chromatophores concentrated on longitudinal zone between flank and dorsum; sometimes dark grey bars on flank anterior to caudal peduncle, when fish exposed to strong sunlight. Dorsum light brown. Venter white. Side of head pale metallic yellowish green to metallic purplish blue, sometimes dark grey when fish exposed to strong sunlight. Lower jaw light brown. Iris light yellowish to greenish brown. Unpaired fins yellowish hyaline with brown dots; round black spot on dorsal portion of caudal fin usually reaching fin margin, anteriorly bordered by small, triangular pale yellow spot. Paired fins hyaline. Fig. 11. Brazil: Pará: Primavera; pool close to creek near forest border, typical habitat of Rivulus urophthalmus. Photo by W. J. E. M. Costa. aqua vol. 11 no

13 Wilson J. E. M. Costa Table I. Morphometric data of the R. urophthalmus, R. taeniatus, R. micropus, and R. ornatus. R. urophthalmus R. taeniatus R. micropus R. ornatus males (10) females (10) males (10) females (10) males (6) females (4) males (5) females (4) Standard length (mm) Percents of standard length Body depth Caudal peduncle depth Pre-dorsal length Pre-pelvic length Length of dorsal-fin base Length of anal-fin base Caudal-fin length Pectoral-fin length Pelvic-fin length Head length Percents of head length Head depth Head width Snout length Lower jaw length Eye diameter Lower Amazon basin, including lower Xingu and Tocantins river basins, and adjacent coastal drainages to East, northern Brazil (Fig. 10). Habitat Shallow creeks at sunny places, sometimes in forest border, at depths of about 5-10 cm (Fig. 11). Rivulus taeniatus Fowler, 1945 (Figs 12-16; Table I) Rivulus taeniatus Fowler, 1945: 129 (type locality: Morelia, río Caqueta drainage, Colombia; holotype: ANSP 71720, illustrated by Fowler 1945: 129). Material examined Brazil: Estado do Amazonas: UFRJ 6245, 23; UFRJ 6246, 4 (c&s); creek adjacent to rio Urubuí, rio Urubu basin, Presidente Figueiredo, 2º S W; W. J. E. M. Costa, R. Paiva & D. Ramos, 11 Jun INPA 1847, 1; INPA 1848, 2; pool near igarapé Acará, Reserva Ducke, Manaus; Rosa, 23 Mar INPA 2367, 4; Belém dos Palmares, rio Solimões, between Benjamin Constant and São Paulo de Olivença; R. Silva, 1 May INPA 3905, 3; INPA 3906, 1; igarapé Candiru, km 50 of the Manaus-Itacoatiara road; C. Pereira, 11 Jul UFRJ 3931, 73; pool near igarapé Acará, Reserva Ducke, Manaus; C. Figueiredo & C. Codeço, 21 Sep Estado do Acre: ZUEC non catalogued, 4; Campus Cacimba; C. F. D. Haddad & J. R. Santos, 2 Jan UFRJ 6291, 7; UFRJ 6292, 82; creek between Rio Branco and Senador Guiomard, rio Acre drainage; W. J. E. M. Costa et al., 12 Jun Distinguished from all other congeners by the combination of the following features: anterior portion of trunk slightly deeper than wide, jaws short, snout blunt, tip of anal fin rounded in male, caudal fin rounded in male, pelvic-fin tip usually not reaching anus and never reaching the anterior portion of the anal-fin base in male, dorsal-fin origin on vertical between base of last 2 nd and 3 rd anal-fin rays, dorsal-fin rays 7-9, anal-fin rays 12-15, frontal squamation E-patterned, frontal scales arranged circularly, canal preopercular short and opened, contact organs on flank scales in male, longitudinal series of scales 38-40, gill rakers of first branchial arch 2 + 9, red Fig. 12. Rivulus taeniatus, UFRJ 6246, male, 31.6 mm SL (minutes after collection); Brazil: Amazonas: Presidente Figueiredo. Photo by W. J. E. M. Costa. 143 aqua vol. 11 no

14 Killifish genus Rivulus (Rivulidae) from the Brazilian Amazonas river basin stripes on flank, jaws not distinctively pigmented except by red tip of lower jaw, and round black spot on dorsal portion of caudal-fin in female. Description Morphometric data appear in Table I. Largest specimen, a male 61.1 mm SL. Dorsal profile gently convex from snout to end of dorsal-fin base, approximately straight on caudal peduncle. Ventral profile slightly convex from lower jaw to end of anal-fin base, about straight on caudal peduncle. Body slender, subcylindrical anteriorly, slightly deeper than wide, to compressed posteriorly. Greatest body depth at vertical just in front to pelvic-fin base. Jaws short, snout blunt. Tip of dorsal and anal fins rounded. Caudal fin rounded. Pectoral fin short and rounded, posterior margin reaching vertical at about 60 % of length between pectoral- and pelvic-fin bases. Pelvic fin short and elliptical, often tip not reaching anus, sometimes on urogenital papilla in male. Pelvic-fin bases medially separated by short interspace. Dorsalfin origin on vertical between base of last 2 nd and 3 rd anal-fin rays, and between neural spines of 21st and 23rd vertebrae. Anal-fin origin between pleural ribs of 15 th and 16 th vertebrae. Dorsal-fin rays 7-9; analfin rays 12-15; caudal-fin rays 27-28; pectoral-fin rays 13-14; pelvic-fin rays 7. Scales small, cycloid. Body and head entirely scaled, except anterior ventral surface of head. Body squamation extending over anterior 30 % of caudalfin base; no scales on dorsal and anal-fin bases. Frontal squamation E-patterned; E-scales not overlapping medially; scales arranged in regular circular pattern around A-scale without exposed margins. Longitudinal series of scales 38-40; transverse series of scales 8; scale rows around caudal peduncle Contact organ on each scale of midventral ventral portion of flank in male. Cephalic neuromasts: supraorbital 3 + 3, parietal 1, anterior rostral 1, posterior rostral 1, infraorbital , preorbital 2-3, otic 1, post-otic 2, supratemporal 1, median opercular 1, ventral opercular 2, preopercular 2 + 4, mandibular , lateral mandibular 2. Interhyal minute, cartilaginous. Basihyal subtriangular, width about 55 % length; basihyal cartilage about 10 % basihyal length. Six branchiostegal rays. Second pharyngobranchial teeth 1. Gill rakers of first branchial arch Vomerine teeth 1. Ventral process of posttemporal short. Total vertebrae Coloration in life: Male: Side of body metallic yellowish green to metallic purplish blue ventrally; 7-8 longitudinal rows of red to reddish brown dots, usually in close proximity, forming stripes; usually three, sometimes four or five rows of red dots crossing cau- Fig. 13. Rivulus taeniatus, UFRJ 6246, female, 33.3 mm SL (minutes after collection); Brazil: Amazonas: Presidente Figueiredo. Photo by W. J. E. M. Costa. Fig. 14. Rivulus taeniatus, UFRJ 6291, male, 28.1 mm SL (one day after collection); Brazil: Acre: Rio Branco. Photo by W. J. E. M. Costa. Fig. 15. Rivulus taeniatus, UFRJ 6291, male, 28.5 mm SL (one day after collection); Brazil: Acre: Rio Branco (compare to Fig. 14 to observe slightly different pigmentation patterns in individuals of the same population). Photo by W. J. E. M. Costa. Fig. 16. Rivulus taeniatus, UFRJ 6291, female, 30.9 mm SL (one day after collection); Brazil: Acre: Rio Branco. Photo by W. J. E. M. Costa. aqua vol. 11 no

15 Wilson J. E. M. Costa dal peduncle and reaching caudal-fin base, remaining rows reaching vertical between dorsal and anal-fin bases; dark chromatophores concentrated on longitudinal zone between flank and dorsum. Dorsum light brown. Venter white. Side of head metallic yellowish green to metallic purplish blue, sometimes dark bluish grey when fish exposed to strong sunlight. Lower jaw light brown, often with red tip. Iris light yellowish to greenish brown. Dorsal fin pale light grey with subbasal oblique row brown spots, often forming stripe; distal portion pale yellow. Anal fin pale yellow, basal portion sometimes blue, often with dark grey margin. Caudal fin light grey, dorsal portion pale yellow. Paired fins yellowish hyaline. Female: Side of body light brown, with eight longitudinal rows of dark red to reddish brown dots, sometimes in close proximity, forming stripes; dark chromatophores concentrated on longitudinal zone between flank and dorsum. Dorsum light brown. Venter white. Side of head pale metallic yellowish green to metallic purplish blue, sometimes dark bluish grey when fish exposed to strong sunlight. Lower jaw light brown. Iris light yellowish brown. Unpaired fins yellowish hyaline with faint brown dots; round black spot on dorsal portion of caudal fin reaching fin margin, anteriorly bordered by small, triangular pale yellow spot. Paired fins yellowish hyaline. Western and middle rio Amazonas basin (Fig. 10). Habitat Shallow creeks at sunny places, sometimes in forest border, at depths of about 5-10 cm (Fig. 17). Rivulus micropus (Steindachner, 1863) (Fig. 18; Table I) Fundulus micropus Steindachner, 1863: 184 (type locality: Rio Negro, Brazil; holotype: NMW 77762; photographs and X-ray of lectotype in Huber 1991: 67, fig. 2). Rivulus compressus Henn, 1916: 111 (type locality: Manáos [now Manaus]; emended as igarapé da Cachoeira Grande, 2 miles out of Manaos, near mouth of rio Negro by Eigenmann 1911; holotype: FMNH 57003, illustrated by Henn 1916: fig. 1). Material examined Brazil: Estado do Amazonas: UFRJ 6288, 2; creek at the road Manaus-Manacapuru, S W; W. J. E. M. Costa, R. Paiva & D. Ramos, 9 Jun UFRJ 6289, 3; stream at the road Manacapuru-Novo Airão, lower rio Negro basin, S W; W. J. E. M. Costa, R. Paiva & D. Ramos, 9 Jun MZUSP 38307, 13; MZUSP 38449, 2 (c&s); lago Buiuçu, Ati-Paraná, NW of Fonte Boa; EPA, Oct INPA 1837, 3 (1c&s); FUA, Manaus; J. Zuanon, J. Porto & E. N. S. Silva, 10 May INPA 2371, 2; Distrito Industrial, Manaus; J. Zuanon, 21 Nov Fig. 17. Brazil: Amazonas: Presidente Figueiredo; creek close to rio Urubuí, habitat of Rivulus taeniatus. Photo by W. J. E. M. Costa. Fig. 18. Rivulus micropus, UFRJ 6288, male, 31.9 mm SL (one day after collection); Brazil: Amazonas: Manacapuru. Photo by W. J. E. M. Costa. 145 aqua vol. 11 no

16 Killifish genus Rivulus (Rivulidae) from the Brazilian Amazonas river basin Distinguished from all other congeners by the combination of the following features: anterior portion of trunk slightly deeper than wide, jaws slightly elongated, snout pointed, tip of anal fin slightly pointed in male, caudal fin rounded in male, pelvicfin tip reaching anterior portion of anal-fin base in male, dorsal-fin origin on vertical between base of penultimate and last anal-fin ray, dorsal-fin rays 7-9, anal-fin rays 13-15, frontal squamation E or D-patterned, frontal scales arranged circularly, canal preopercular short and opened, contact organs on flank scales in male, longitudinal series of scales 40-45, gill rakers of first branchial arch , pink stripes on flank, jaws not distinctively pigmented, and round black spot on dorsal portion of caudal fin in female. Description Morphometric data appear in Table I. Largest specimen, a male 42.8 mm SL. Dorsal profile gently convex from snout to end of dorsal-fin base, approximately straight on caudal peduncle. Ventral profile slightly convex from lower jaw to end of anal-fin base, about straight on caudal peduncle. Body slender, subcylindrical anteriorly, slightly deeper than wide, to compressed posteriorly. Greatest body depth at vertical just in front to pelvic-fin base. Jaws slightly elongated, snout pointed. Tip of dorsal rounded; tip of anal fin slightly pointed in male, rounded in female. Caudal fin rounded. Pectoral fin short and rounded, posterior margin reaching vertical at about 80 % of distance between pectoral and pelvic-fin bases. Pelvic fin elliptical, tip reaching between urogenital papilla and base of 2 nd anal-fin ray in male, and urogenital papilla in female. Pelvic-fin bases medially separated by short interspace. Dorsal-fin origin on vertical between base of penultimate and last anal-fin ray, and between neural spines of 24 th and 25 th vertebrae. Anal-fin origin between pleural ribs of 16 th and 17 th vertebrae. Dorsal-fin rays 7-9; anal-fin rays 13-15; caudal-fin rays 29-30; pectoral-fin rays 15; pelvic-fin rays 7-8. Scales small, cycloid. Body and head entirely scaled, except anterior ventral surface of head. Body squamation extending over anterior % of caudal-fin base; no scales on dorsal and anal-fin bases. Frontal squamation E or D-patterned; E-scales not overlapping medially; scales arranged in regular circular pattern around A-scale without exposed margins. Longitudinal series of scales 40-45; transverse Fig. 19. Geographic distribution of: Rivulus beniensis (lozenges), R. dibaphus (dots), R. micropus (stars), R. strigatus (triangles), and R. tecminae (inverted triangles). One symbol may represent more than one collecting site. aqua vol. 11 no

17 Wilson J. E. M. Costa series of scales 8; scale rows around caudal peduncle 16. Contact organ on each scale of midventral ventral portion of flank in male. Cephalic neuromasts: supraorbital 3 + 3, parietal 1, anterior rostral 1, posterior rostral 1, infraorbital , preorbital 3, otic 1, post-otic 2, supratemporal 1, median opercular 1, ventral opercular 2, preopercular 2 + 4, mandibular 4 + 2, lateral mandibular 3. Interhyal minute, cartilaginous. Basihyal subtriangular, width about 55% length; basihyal cartilage about 25% basihyal length. Six branchiostegal rays. Second pharyngobranchial teeth 3-4. Gill rakers of first branchial arch Vomerine teeth 1. Ventral process of posttemporal long. Total vertebrae 35. Coloration in life: Male: Side of body dark blue, with 8 narrow pink stripes, of which 3-5 reaching caudal-fin base; dark chromatophores concentrated on longitudinal zone between flank and dorsum. Dorsum light brown. Venter white. Side of head dark purplish blue. Jaws dark brown. Iris brown. Unpaired fins pale yellow with brown spots. Paired fins hyaline. Female: Similar to male, but flank stripes darker, and round black spot on dorsal portion of caudal fin reaching fin margin, anteriorly bordered by small, triangular pale yellow spot. Middle rio Amazonas basin (Fig. 19). Habitat Margins of streams and lakes at sunny places, sometimes in forest border, at depths of about cm (Fig. 20). Subgenus Anablepsoides Huber, 1992 Anablepsoides Huber, 1992: 43 (type species: Rivulus atratus Garman; type by original designation). Distinguished from the remaining subgenera of Rivulus by the following apomorphic features: rounded rostral cartilage (15.0), external medial teeth of premaxilla and dentary laterally displaced (20.1), long, acuminate caudal fin (76.1, 77.3), frontal squamation S-patterned (80.4; also occurring in Owiyeye), oblique dark grey on flank in male when exposed to sunlight (93.3), and transverse stripe through chin (98.2; also occurring in Owiyeye). Included species Rivulus atratus Garman, 1895 and R. ornatus Garman, Amazonas river basin, in Brazil and Peru. Rivulus ornatus Garman, 1895 (Fig. 21; Table I) Rivulus ornatus Garman, 1895: 139 (type locality: Silva, Cudajas, Lago Aleixo, Lake Hyanuary [four distinct localities in the Brazilian Amazon, Estado do Amazonas: Silves, Codajás, lago Aleixo and paraná do Janauari]; lectotype: MCZ 6266, designated by Huber 1992: 347). Rivulus obscurus Garman, 1895: 140 (type locality: Lake Hyanuary [paraná do Janauari, Estado do Amazonas, Brazil]; lectotype: MCZ 6853, designated by Huber 1992: 336). Fig. 20. Brazil: Amazonas: Manacapuru; stream near road Manaus-Manacapuru, habitat of Rivulus micropus. Photo by W. J. E. M. Costa. Fig. 21. Rivulus ornatus, not preserved, male, about 20.0 mm SL (about one week after collection); Brazil: Amazonas: Manaus. Photo by W. J. E. M. Costa. 147 aqua vol. 11 no

18 Killifish genus Rivulus (Rivulidae) from the Brazilian Amazonas river basin Material examined Brazil: Estado do Amazonas: MCZ 6854, 4 paralectotypes; paraná do Janauari, 3 12 S 60º5 W; L. Agassiz, 27 Oct MCZ 98664, 1 paralectotype of R. obscurus; same data as MCZ UFRJ 7499, 28; stream tributary to rio Sanasani, Silves; EPA, 7 Oct INPA 3908, 3; igarapé Candiru, km 50 of the road Manaus-Itacoatiara; C. Pereira, 11 Jul Estado do Pará: MZUSP 37208, 3; lago Jacaré, rio Trombetas; EPA, 7 Nov MZUSP 38440, 2 (c&s); rio Curuinapui; EPA, 26 Jan Distinguished from all other congeners by the combination of the following features: anterior portion of trunk slightly wider than deep, jaws short, snout blunt, tip of anal fin rounded in male, caudal fin elliptical to acuminate in male, pelvicfin tip reaching the anterior portion of the anal-fin base in male, dorsal-fin origin posterior to anal-fin base, dorsal-fin rays 5-7, anal-fin rays 9-11, frontal squamation S-patterned, contact organs absent, frontal scales arranged circularly, canal preopercular short and opened, longitudinal series of scales 29-32, gill rakers of first branchial arch 1 + 7, oblique rows of red dots on flank in male, transverse black bar through the chin, and no black spot on dorsal portion of caudal-fin. Description Morphometric data appear in Table I. Largest specimen, a male 21.1 mm SL. Dorsal profile gently convex from snout to end of dorsal-fin base, approximately straight on caudal peduncle. Ventral profile weakly convex from lower jaw to end of anal-fin base, about straight on caudal peduncle. Body slender, subcylindrical anteriorly, wider than deep, to compressed posteriorly. Greatest body depth at vertical just in front of pelvic-fin base. Jaws short, snout blunt. Tip of dorsal and anal fins rounded. Caudal fin elliptical, often pointed in male. Pectoral fin rounded, posterior margin reaching vertical between pelvic-fin base and anus in male, and vertical just anterior to pelvic-fin base in female. Pelvic fin elliptical, tip reaching between urogenital papilla and base of 4th anal-fin ray in male, between urogenital papilla and anal-fin origin in female. Pelvic-fin bases medially separated by short Fig. 22. Geographic distribution of: Rivulus ornatus (stars), R. uakti (inverted triangle), R. uatuman (dot), and R. zygonectes (lozenges). One symbol may represent more than one collecting site. aqua vol. 11 no

19 Wilson J. E. M. Costa interspace. Dorsal-fin origin on vertical just posterior to anal-fin base, between neural spines of 20 th and 21 st vertebrae. Anal-fin origin between pleural ribs of 13 th and 14 th vertebrae. Dorsal-fin rays 5-7; anal-fin rays 9-11; caudal-fin rays 24; pectoral-fin rays 12-13; pelvic-fin rays 7. Scales small, cycloid. Body and head entirely scaled, except anterior ventral surface of head. Body squamation extending over anterior 20 % of caudal-fin base; no scales on dorsal and anal-fin bases. Frontal squamation S-patterned; E-scales not overlapping medially; scales arranged in regular circular pattern around A-scale without exposed margins. Longitudinal series of scales 29-32; transverse series of scales 7; scale rows around caudal peduncle 16. Contact organs absent. Cephalic neuromasts: supraorbital 3 + 3, parietal 1, anterior rostral 1, posterior rostral 1, infraorbital , preorbital 2, otic 1, post-otic 1, supratemporal 1, median opercular 1, ventral opercular 2, preopercular 2 + 4, mandibular , lateral mandibular 3. Interhyal minute, cartilaginous. Basihyal subtriangular, width about 50% length; basihyal cartilage about 10% basihyal length. Six branchiostegal rays. Second pharyngobranchial teeth 1-2. Gill rakers of first branchial arch Vomerine teeth 1. Ventral process of posttemporal absent. Total vertebrae Coloration in life: Male: Side of body pale blue, usually with 8 narrow light brown vertical lines, overlapped by oblique rows of red dots; dark chromatophores concentrated on longitudinal zone between flank and dorsum. Dorsum light brown with transverse dark brown bars. Venter brown. Side of head and infraorbital region dark metallic blue with red dots. Jaws light brown; dark brown to black transverse bar just below lower jaw. Iris brown. Dorsal and anal fins pale yellow to pale blue, with red to reddish brown bars. Dorsal portion of caudal fin pale yellow to pale blue with dark red narrow bars, median portion dark brown, and ventral portion reddish orange. Pectoral fin hyaline. Pelvic fin pale yellow. Female: Side of body light brown with 8 narrow brown vertical lines, and 5-7 oblique dark brown bars; dark chromatophores concentrated on longitudinal zone between flank and dorsum. Dorsum light brown with transverse brown bars. Venter light brown. Side and ventral portion of head brown. Jaws light brown; dark brown to black Fig. 23. Geographic distribution of: Rivulus amanapira (inverted triangle), R. atratus (stars), R. kirovskyi (dot), and R. litteratus (lozenges). One symbol may represent more than one collecting site. 149 aqua vol. 11 no

20 Killifish genus Rivulus (Rivulidae) from the Brazilian Amazonas river basin transverse bar just below lower jaw. Iris brown. Unpaired fins hyaline with transverse narrow dark brown bars. Paired fins hyaline. Middle rio Amazonas basin, Brazil (Fig. 22). Habitat Stagnant waters in sunny places near forest border, with dense aquatic vegetation, about cm deep. Rivulus atratus Garman, 1895 Rivulus atratus Garman, 1895: 140 (type locality: Jutahy [now Jutaí, Estado do Amazonas, Brazil]; lectotype: MCZ 6318, designated by Huber 1992: 102). Material examined Brazil: Estado do Amazonas: MCZ 98675, 1 paralectotype; Jutaí; Thayer Expedition, Sep MZUSP 38310, 1; MZUSP 38449, 1 (c&s); rio Içapó, mouth of rio Jutaí; EPA, 22 Oct MZUSP 38494, 12; lago Miuá, above Codajás; EPA, 25 Sep Distinguished from all other congeners by the combination of the following features: anterior portion of trunk wider than deep, jaws short, snout blunt, tip of anal fin rounded in male, caudal fin elliptical to acuminate in male, pelvic-fin tip not reaching to urogenital papilla in male, dorsal-fin origin posterior to anal-fin base, dorsal-fin rays 5-6, anal-fin rays 8-10, frontal squamation S-patterned, frontal scales arranged circularly, canal preopercular short and opened, contact organs absent, longitudinal series of scales 32-34, gill rakers of first branchial arch 1 + 7, dark brown oblique bars on flank, transverse black bar through the chin, and no black spot on dorsal portion of caudal fin. Also distinguished from all other congeners in having venter dark brown to black and dark brown spots on pectoral fin. Middle rio Amazonas basin, Brazil and Peru (Fig. 23). Habitat Still waters close to river and lake margins. Benirivulus, new subgenus Type species: Rivulus beniensis Myers, Two autapomorphic conditions were found in Benirivulus, which are not present in other congeners: a colour pattern of anal fin, consisting of one or two subbasal rows of reddish brown close dots, sometimes forming stripes, and a broad dark grey distal zone on the dorsal fin (Fig. 24). Etymology The name Benirivulus is derived from Beni, an important Amazonian river, and rivulus, from the Latin meaning stream, in reference to the occurrence of the new taxon in streams of that river basin. Gender masculine. Included species Only R. beniensis, the type species of the subgenus. Madeira river drainage, Amazonas river basin, in Bolivia and Brazil. Rivulus beniensis Myers, 1927 (Fig. 24; Table II) Rivulus strigatus (non R. strigatus Regan); Pearson, 1925: 51 (misidentification). Rivulus beniensis Myers, 1927b: 133 (type locality: Ivon, Rio Beni [lower río Beni, just above confluence with río Madre de Díos, Departamento de Beni], Bolivia; lectotype: USNM 86776, designated by Fels & Huber 1985: 35). Rivulus beniensis lacustris Myers, 1927b: 133 (type locality: lagoons along shores of Lake Rogoagua [lago Rogoaguado, río Yata basin, which drains into río Mamoré, immediately above confluence Fig. 24. Rivulus beniensis, UFRJ 5885, male, 19.6 mm SL (one day after collection); Brazil: Rondônia: between Mutum Paraná and Abunã. Photo by W. J. E. M. Costa. aqua vol. 11 no

21 Wilson J. E. M. Costa Table II. Morphometric data of Rivulus beniensis, R. strigatus, and R. dibaphus. R. beniensis R. strigatus R. dibaphus males (10) females (10) males (10) females (7) males (9) females (6) Standard length (mm) Percents of standard length Body depth Caudal peduncle depth Pre-dorsal length Pre-pelvic length Length of dorsal-fin base Length of anal-fin base Caudal-fin length Pectoral-fin length Pelvic-fin length Head length Percents of head length Head depth Head width Snout length Lower jaw length Eye diameter with río Beni], Bolivia; lectotype: UMMZ 66396, designated by Fels & Huber 1985: 35). Rivulus bolivianus Seegers, 1988: 172 (type locality: laguna Suarez, ca. 4 km SW Trinidad, río Mamoré, Bolivia; holotype: ZFMK 14602). Material examined Bolivia: Departamento de Beni: CBF 1886, 54; CBF 1873, 39; Espírito, Estación Biológica Beni; J. Sarmiento, Apr Brazil: Estado de Rodônia: UFRJ 5884, 67; UFRJ 5885, 4 (c&s); swamp near road BR-364, between Mutum-Paraná and Abunã, rio Madeira basin, 9º S 65º4 9.9 W; W. J. E. M. Costa, S. Lima & A. Pinto, 6 Jun UFRJ 5881, 6; swamp close to rio Mamoré, near Guajará-Mirim, 10º S 65º W; W. J. E. M. Costa, S. Lima & A. Pinto, 7 Jun Estado de Mato Grosso: swamp at km 2 of the road between Vila Bela and Casal Vasco, near rio Guaporé; W. J. E. M. Costa, M. I. Landim, R. D Arrigo & C. Moreira, 29 Apr Distinguished from all other congeners by the combination of the following features: anterior portion of trunk slightly deeper than wide, jaws short, snout blunt, tip of anal fin rounded in male, caudal fin rounded in male, pelvic-fin tip reaching the anterior portion of the anal-fin base in male, dorsal-fin origin on vertical between base of 9 th and 10 th anal-fin rays, dorsal-fin rays 7-8, anal-fin rays 11-13, frontal squamation E-patterned, frontal scales arranged circularly, canal preopercular short and opened, contact organs on flank scales in male, longitudinal series of scales 29-32, gill rakers of first branchial arch 1 + 7, longitudinal rows of reddish brown dots stripes on flank in male, jaws black, and round black spot on dorsal portion of caudal-fin in female. Description Morphometric data appear in Table II. Largest specimen, a female 28.8 mm SL. Dorsal profile gently convex from snout to end of dorsal-fin base, approximately straight on caudal peduncle. Ventral profile slightly convex from lower jaw to end of analfin base, about straight on caudal peduncle. Body slender, subcylindrical anteriorly, slightly deeper than wide, to compressed posteriorly. Greatest body depth at vertical just in front to pelvic-fin base. Jaws short, snout blunt. Tip of dorsal and anal fins rounded. Caudal fin rounded. Pectoral fin rounded, posterior margin reaching vertical at about 80% length between pectoral-fin and pelvic-fin bases. Pelvic fin elliptical, tip reaching between urogenital papilla and anal-fin origin in male, between anus and urogenital papilla in female. Pelvic-fin bases medially separated by short interspace. Dorsal-fin origin on vertical between base of 9 th and 10 th anal-fin rays, and between neural spines of 19 th and 21 st vertebrae. Anal-fin origin between pleural ribs of 15 th and 16 th vertebrae. Dor- 151 aqua vol. 11 no

22 Killifish genus Rivulus (Rivulidae) from the Brazilian Amazonas river basin sal-fin rays 7-8; anal-fin rays 11-13; caudal-fin rays 23-26; pectoral-fin rays 13; pelvic-fin rays 6. Scales small, cycloid. Body and head entirely scaled, except anterior ventral surface of head. Body squamation extending over anterior 25 % of caudalfin base; no scales on dorsal and anal-fin bases. Frontal squamation E-patterned; E-scales not overlapping medially; scales arranged in regular circular pattern around A-scale without exposed margins. Longitudinal series of scales 29-32; transverse series of scales 7; scale rows around caudal peduncle 16. Contact organ on each scale of midventral portion of flank in male. Cephalic neuromasts: supraorbital 3 + 3, parietal 1, anterior rostral 1, posterior rostral 1, infraorbital , preorbital 2, otic 1, post-otic 1, supratemporal 1, median opercular 1, ventral opercular 1, preopercular 2 + 4, mandibular 3 + 1, lateral mandibular 2. Interhyal minute, cartilaginous. Basihyal subtriangular, width about 35 % length; basihyal cartilage about 30 % basihyal length. Six branchiostegal rays. Second pharyngobranchial teeth 2. Gill rakers of first branchial arch Vomerine teeth 2. Ventral process of posttemporal absent. Total vertebrae Coloration in life: Male: Side of body metallic yellowish green; six longitudinal rows of reddish brown dots, of which often two or three rows with sparse dots or absent, middle row forming stripe; dark chromatophores concentrated on longitudinal zone between flank and dorsum, often forming short oblique dark brown bars when fish exposed to strong sunlight. Dorsum light brown. Venter white. Side of head metallic yellowish green with small dark brown spots. Lower jaw black. Iris light yellowish with black vertical stripe. Dorsal fin pale yellow with subbasal row of reddish brown dots and dark grey distal stripe. Anal fin light blue on basal portion and pale yellow on distal portion, with one or sometimes two subbasal rows of reddish brown dots and dark grey distal stripe. Caudal fin light grey. Paired fins hyaline, anterior margin of pelvic fin dark grey. Female: Side of body with irregularly shaped brown blotches, forming longitudinal row of rounded light brown interspaces on ventral portion; sometimes almost inconspicuous rows of brown dots coalesced to brown blotches; dark chromatophores concentrated on longitudinal zone between flank and dorsum, often forming short oblique dark brown bars when fish exposed to strong sunlight. Dorsum light brown. Venter white. Side of head pale metallic yellowish green with small dark brown spots. Lower jaw black. Iris light yellowish with black vertical stripe. Dorsal fin hyaline with two subbasal rows of brown dots and grey distal stripe. Anal fin hyaline with two or three subbasal rows of brown dots and grey distal stripe. Caudal fin light grey; round black spot on dorsal portion of caudal fin reaching caudal-fin margin, anteriorly bordered by small, triangular pale yellow spot. Paired fins hyaline, anterior margin of pelvic fin grey. Rio Madeira basin, Bolivia and Brazil (Fig. 19). Habitat Stagnant waters in sunny places near forest border, with dense aquatic vegetation, about cm deep (Fig. 25). Subgenus Laimosemion Huber, 1999 Laimosemion Huber, 1999: 49 (type species: Rivulus geayi Vaillant; type by original designation). Distinguished from other rivulids by having bifid epipleural ribs (43.1). Fig. 25. Brazil: Rondônia: between Mutum Paraná and Abunã; lake at the border of forest, habitat of Rivulus beniensis. Photo by W. J. E. M. Costa. Included species Rivulus agilae Hoedeman, 1954, R. dibaphus Myers, 1927, R. breviceps Eigenmann, 1909, R. cladophorus Huber, 1991, R. corpulentus Thomerson aqua vol. 11 no

23 Wilson J. E. M. Costa & Taphorn, 1993, R. frenatus Eigenmann, 1912, R. geayi Vaillant, 1899, R. gransabanae Lasso, Taphorn & Thomerson, 1992, R. lyricauda Thomerson, Berkenkamp & Taphorn, 1991, R. nicoi Thomerson & Taphorn, 1992, R. strigatus Regan, 1912, R. torrenticola Vermeulen & Isbrücker, 2000, and R. xiphidius Huber, Orinoco river basin, Guiana rivers, eastern Amazonas river basin and adjacent coastal areas in Venezuela, Guiana, Suriname, Guyana and Brazil. Rivulus strigatus Regan, 1912 (Figs ; Table II) Rivulus strigatus Regan, 1912: 502 (type locality: Amazon [Belém, Pará, Brazil]; holotype: BMNH ). R. geayi (non R. geayi Vaillant); Huber 1991: (equivocal synonymy). Material examined Brazil: Estado do Pará: UFRJ 6249, 25; UFRJ 6250, 6; UFRJ 6251, 4 (c&s); stream at the road PA-446, Primavera, S W; W. J. E. M. Costa, R. Paiva & D. Ramos, 19 Jun UFRJ 6262, 1; stream at ilha do Mosqueiro, road PA-391, Belém, S W; W. J. E. M. Costa, R. Paiva & D. Ramos, 21 Jun UFRJ 4075, 16; UFRJ 4078, 11; igarapé Maguary, Belém; A. Sarraf & E. Nogueira, 1 Aug UFRJ 1820, 1 (c&s); Belém; M. Lacerda, Distinguished from all other congeners by the combination of the following features: anterior portion of trunk slightly deeper than wide, jaws short, snout blunt, tip of anal fin slightly pointed in male, caudal fin rounded in male, pelvic-fin tip reaching the anterior portion of the anal-fin base in male, dorsal-fin origin on vertical between base of 7 th and 8 th anal-fin rays, dorsal-fin rays 8-9, anal-fin rays 11-13, frontal squamation F-patterned, frontal scales arranged circularly, canal preopercular short and opened, contact organs on flank scales in male, longitudinal series of scales 30-32, gill rakers of first branchial arch 1 + 7, longitudinal rows of red spots on anterior portion of flank and red chevron-like oblique bars on posterior portion of flank in male, jaws black, and no black spot on dorsal portion of caudal-fin. Description Morphometric data appear in Table II. Largest specimen, a male 26.5 mm SL. Dorsal profile slightly convex from snout to end of dorsal-fin base, approximately straight on caudal peduncle. Ventral profile weakly convex from lower jaw to end of analfin base, about straight on caudal peduncle. Body slender, subcylindrical anteriorly, slightly deeper than wide, to compressed posteriorly. Greatest body depth at vertical just in front to pelvic-fin base. Jaws short, snout blunt. Tip of dorsal and anal fins slightly pointed in male, rounded in female. Caudal fin rounded. Pectoral fin rounded, posterior margin reaching vertical at about 75 % length between pectoral-fin and pelvic-fin bases. Pelvic fin elliptical, tip reaching between base of 1 st and 2 nd anal-fin rays in male, between urogenital papilla and base of 1 st anal-fin ray in female. Pelvic-fin bases medially in contact. Dorsal-fin ori- Fig. 26. Rivulus strigatus, UFRJ 6262, male, 23.0 mm SL (two days after collection); Brazil: Pará: Belém. Photo by W. J. E. M. Costa. Fig. 27. Rivulus strigatus, UFRJ 6250, male, 26.5 mm SL (one day after collection); Brazil: Pará: Primavera. Photo by W. J. E. M. Costa. Fig. 28. Rivulus strigatus, UFRJ 6250, female, 22.2 mm SL (one day after collection); Brazil: Pará: Primavera. Photo by W. J. E. M. Costa. 153 aqua vol. 11 no

24 Killifish genus Rivulus (Rivulidae) from the Brazilian Amazonas river basin gin on vertical between base of 7 th and 8 th anal-fin rays, and between neural spines of 18 th and 19 th vertebrae. Anal-fin origin between pleural ribs of 14 th and 15 th vertebrae. Dorsal-fin rays 8-9; anal-fin rays 11-13; caudal-fin rays 28; pectoral-fin rays 14-15; pelvic-fin rays 6. Scales small, cycloid. Body and head entirely scaled, except anterior ventral surface of head. Body squamation extending over anterior 25 % of caudalfin base; no scales on dorsal- and anal-fin bases. Frontal squamation F-patterned; E-scales not overlapping medially; scales arranged in regular circular pattern around A-scale without exposed margins. Longitudinal series of scales 30-32; transverse series of scales 7; scale rows around caudal peduncle 16. Contact organ on each scale of midventral portion of flank in male. Cephalic neuromasts: supraorbital 3 + 3, parietal 1, anterior rostral 1, posterior rostral 1, infraorbital , preorbital 2, otic 1, post-otic 1, supratemporal 1, median opercular 1, ventral opercular 2, preopercular 2 + 4, mandibular 3 + 1, lateral mandibular 2-3. Interhyal minute, cartilaginous. Basihyal subtriangular, width about 50 % length; basihyal cartilage about 25 % basihyal length. Six branchiostegal rays. Second pharyngobranchial teeth absent. Gill rakers of first branchial arch Vomerine teeth absent. Ventral process of posttemporal absent. Total vertebrae Coloration in life: Male: Side of body metallic blue or greenish blue; four to five longitudinal rows of red dots on anterior half of flank, and red chevronlike oblique bars with vertex anteriorly directed on posterior half of flank; dark blue humeral blotch. Dorsum light brown. Venter white. Side of head metallic greenish blue with small red spots; infraorbital region yellow. Jaws black. Iris brown, anterior and posterior portion green. Dorsal fin light blue with red bars on basal and posterior zones, red on anterior and distal portions; sometimes pale yellow anterior margin. Anal fin light blue with grey dots on basal and posterior portions; narrow dark reddish grey distal stripe. Upper two-thirds of caudal fin light red with transverse rows of small blue spots, lower third greenish blue; narrow dark reddish grey ventral stripe. Pectoral fin hyaline. Pelvic fin light blue with dark reddish grey anterior margin. Female: Side of body light grey with small dark purplish brown spots arranged both in overlapped longitudinal and oblique rows; dark grey humeral blotch; dark chromatophores concentrated on longitudinal zone between flank and dorsum, often forming short transverse dark brown bars when fish exposed to strong sunlight. Dorsum light brown. Venter white. Side of head pale blue with small dark brown spots; infraorbital region pale yellow. Jaws black. Iris brown. Dorsal fin pale yellow on basal and posterior portions, light purplish grey on distal and anterior portions. Anal fin pale yellow to pale pink, basal portion light blue; distal margin dark grey. Caudal fin pale yellow with dark brown bars on upper two- thirds of fin. Pectoral fin hyaline. Pelvic fin pale yellow with dark grey anterior margin. River basins close to the right bank of rio Amazonas mouth (Fig. 19). Fig. 29. Brazil: Pará: Primavera; clear water stream, habitat of Rivulus strigatus. Photo by W. J. E. M. Costa. Habitat Margins of clear water streams with moderate current, sand bottom, at depth of about cm (Fig. 29). aqua vol. 11 no

25 Wilson J. E. M. Costa Rivulus dibaphus Myers, 1927 (Figs 30-32; Table II) Rivulus dibaphus Myers, 1927: 121 (type locality: Igarapé do Ajamuri, Lower Amazon [corrected by S. O. Kullander in Huber 1991: 70 as Ajamuri or Agamuri, a beach in Lago Grande at mouth of rio Maicuru, just east of Santarém, Pará, Brazil]; lectotype: CAS 44214, designated by Huber 1992: 184). R. geayi (non R. geayi Vaillant); Huber, 1991: (equivocal synonymy). Material examined Brazil: Estado do Pará: CAS 44214, lectotype; CAS 44215, 6; Igarapé do Ajamuri, Santarém; C. Ternetz, Jul UFRJ 6283, 10; UFRJ 6284, 6 (c&s); UFRJ 6285, 4; stream 5 km S of Alter do Chão, Santarém, S W; W. J. E. M. Costa, R. Paiva & D. Almeida, 14 Jun. Fig. 30. Rivulus dibaphus, UFRJ 6284, male, 24.8 mm SL (one day after collection); Brazil: Pará: Santarém. Photo by W. J. E. M. Costa. Fig. 31. Rivulus dibaphus, UFRJ 6284, male, 22.3 mm SL (one day after collection); Brazil: Pará: Santarém. Photo by W. J. E. M. Costa. Fig. 32. Rivulus dibaphus, UFRJ 6284, female, 21.8 mm SL (one day after collection); Brazil: Pará: Santarém. Photo by W. J. E. M. Costa UFRJ 6286, 2; stream tributary to rio Tapajós, Porto Novo, Belterra, S W; W. J. E. M. Costa, R. Paiva & D. Almeida, 14 Jun UFRJ 6286, 7; stream tributary to rio Tapajós, near Porto Novo, Belterra, S W; W. J. E. M. Costa, R. Paiva & D. Almeida, 14 Jun INPA 2370, 8 (1c&); igarapé do Patenós, rio Trombetas basin; J. Zuanon & E. Ferreira, 2 Dec Distinguished from all other congeners by the combination of the following features: anterior portion of trunk slightly deeper than wide, jaws short, snout blunt, tip of anal fin slightly pointed in male, caudal fin subtruncate in male, pelvic-fin tip reaching the anterior portion of the anal-fin base in male, dorsal-fin origin on vertical between base of 7 th and 8 th anal-fin rays, dorsal-fin rays 9-10, anal-fin rays 12-13, frontal squamation E-patterned, frontal scales arranged circularly, canal preopercular short and opened, contact organs on flank scales in male, longitudinal series of scales 30-32, gill rakers of first branchial arch 1 + 9, longitudinal rows of red spots on anterior portion of flank and red chevron-like oblique bars on posterior portion of flank in male, jaws black, and no black spot on dorsal portion of caudal-fin. Description Morphometric data appear in Table II. Largest specimen, a male 26.5 mm SL. Dorsal profile slightly convex from snout to end of dorsal-fin base, approximately straight on caudal peduncle. Ventral profile weakly convex from lower jaw to end of analfin base, about straight on caudal peduncle. Body slender, subcylindrical anteriorly, slightly deeper than wide, to compressed posteriorly. Greatest body depth at vertical just in front to pelvic-fin base. Jaws short, snout blunt. Tip of dorsal and anal fins slightly pointed in male, rounded in female. Caudal fin subtruncate in male, rounded in female. Pectoral fin rounded, posterior margin reaching vertical at about % length between pectoral-fin and pelvic-fin bases. Pelvic fin elliptical, tip reaching between base of 2 nd and 3 rd anal-fin rays in male, between urogenital papilla and base of 2 nd anal-fin ray in female. Pelvic-fin bases medially in contact. Dorsal-fin origin on vertical between base of 7 th and 8 th anal-fin rays, and between neural spines of 16 th and 18 th vertebrae. Anal-fin origin between pleural ribs of 13 th and 14 th 155 aqua vol. 11 no

26 Killifish genus Rivulus (Rivulidae) from the Brazilian Amazonas river basin vertebrae. Dorsal-fin rays 9-10; anal-fin rays 12-13; caudal-fin rays 28-31; pectoral-fin rays 14-15; pelvic-fin rays 6-7. Scales small, cycloid. Body and head entirely scaled, except anterior ventral surface of head. Body squamation extending over anterior 30 % of caudal-fin base; no scales on dorsal and anal-fin bases. Frontal squamation E-patterned; E-scales not overlapping medially; scales arranged in regular circular pattern around A-scale without exposed margins. Longitudinal series of scales 30-32; transverse series of scales 7; scale rows around caudal peduncle 16. Contact organ on each scale of midventral portion of flank in male. Cephalic neuromasts: supraorbital 3 + 3, parietal 1, anterior rostral 1, posterior rostral 1, infraorbital , preorbital 2-3, otic 1, post-otic 1, supratemporal 1, median opercular 1, ventral opercular 2, preopercular 2 + 4, mandibular 3 + 1, lateral mandibular 2-3. Interhyal minute, cartilaginous. Basihyal subtriangular, width about 45% length; basihyal cartilage about 25% basihyal length. Six branchiostegal rays. Second pharyngobranchial teeth absent. Gill rakers of first branchial arch Vomerine teeth absent. Ventral process of posttemporal absent. Total vertebrae Coloration in life: Male: Side of body metallic blue, bluish black on caudal peduncle; four to five longitudinal rows of red dots on anterior half of flank, and red chevron-like oblique bars with vertex anteriorly directed on posterior half of flank; dark blue humeral blotch. Dorsum light brown. Venter white. Side of head metallic greenish blue with small red spots; infraorbital region yellow. Jaws black. Iris brown, anterior and posterior portion green. Dorsal fin light blue with dark red reticulation. Anal fin light blue to pale yellow on distal portion, with grey dots or short bars on basal and posterior portions; narrow dark reddish grey distal stripe. Caudal fin pale blue with five or six dark red bars not extending to ventralmost portion of fin; usually black ventral stripe. Pectoral fin hyaline. Pelvic fin light blue with dark reddish grey anterior margin. Female: Side of body light grey with small dark reddish brown spots arranged both in overlapped longitudinal and oblique rows, often alternating with bright greenish blue small spots; dark grey humeral blotch; dark chromatophores concentrated on longitudinal zone between flank and dorsum, often forming short transverse dark brown bars when fish exposed to strong sunlight. Dorsum light brown. Venter white. Side of head pale blue with small dark brown spots; infraorbital region pale yellow. Jaws black. Iris brown. Dorsal fin pale yellow with grey dots. Anal fin pale yellow, basal portion light blue; distal margin dark grey. Caudal fin pale yellow with dark brown dots on upper two thirds of fin. Pectoral fin hyaline. Pelvic fin pale yellow with dark grey anterior margin. Lower Tapajós and lower Trombetas river basins, and adjacent areas in eastern Amazonas river basin (Fig. 19). Habitat Margins of clear water streams with moderate current, sand bottom, at depths of about cm (Fig. 33). Owiyeye, new subgenus Type species: Rivulus amanapira Costa, Fig. 33. Brazil: Pará: Santarém. clear water stream, habitat of Rivulus dibaphus. Photo by W. J. E. M. Costa. Distinguished from all other subgenera of Rivulus aqua vol. 11 no

27 Wilson J. E. M. Costa in having the following apomorphic features: absence of dermosphenotic (3.1), frontal scales transversely arranged (79.0) (Fig. 34A), frontal squamation S-patterned (80.4; also occurring in Anablepsoides) (Fig. 34A), and a transverse stripe through chin (98.2; also occurring in Anablepsoides). Etymology Owiyeye is the popular name used by Tucanos Indians from the upper rio Negro, Brazil, for R. amanapira (Costa 2004f). This name had already been reported by Wallace (2002) in notes made during his journey to the Amazon ( ). Gender masculine. Included species Rivulus altivelis Huber, 1992, R. amanapira Costa, 2004, R. kirovskyi Costa, 2004, R. rectocaudatus Fels & de Rham, 1981, R. romeri Costa, 2003, R. tecminae Thomerson, Nico & Taphorn, 1992, R. uakti Costa, 2004 and R. uatuman Costa, Amazonas and upper Orinoco river basins, in Venezuela, Colombia, Brazil and Peru. Rivulus romeri Costa, 2003 Rivulus romeri Costa, 2003a (type locality: brook tributary to Igarapé Iauiari, about 0º14.31 N, W, which is a tributary of the Uaupés river, itself a tributary of the Negro river, Amazonian basin, Amazonas, Brazil; holotype: MCP 29751). Material examined Brazil: Estado do Amazonas: MCP 29751, holotype; MCP 29752, 1 paratype; UFRJ 5447, 2 paratypes; UFRJ 5448, 4 paratypes (c&s); brook tributary to Igarapé Iauiari, a tributary of the Uaupés river, itself a tributary of the Negro river, Amazonian basin; U. Römer, 21 Feb Distinguished from all other congeners by the combination of the following features: anterior portion of trunk slightly deeper than wide, jaws short, snout blunt, tip of anal fin pointed in male, caudal fin rounded in male, pelvic-fin tip reaching urogenital papilla in male, dorsal-fin origin on vertical between base of 6th and 8th anal-fin rays, dorsal-fin rays 7-8, anal-fin rays 9-10, frontal squamation S- patterned, frontal scales arranged transversely, canal preopercular absent, contact organs absent, longitudinal series of scales 29-30, gill rakers of first branchial arch 1 + 6, longitudinal rows of red dots on flank in male, transverse dark brown bar through the chin, and no distinctive black spot on dorsal portion of caudal-fin. Upper rio Negro drainage (Fig. 10). Habitat Shallow pools within dense forest (U. Römer, pers. comm.). Rivulus kirovskyi Costa, 2004 Rivulus kirovskyi Costa, 2004d: 10 (type locality: Fig. 34. Diagrammatic representation of the frontal squamation patterns in the genus Rivulus: A. R. romeri; B. R. litteratus; C. R. scalaris. Scale bar = 1 mm. 157 aqua vol. 11 no

28 Reserva Ducke, temporary pools near igarapé Acará, lower rio Negro drainage, rio Amazonas basin, about 3 0 S W, Manaus, Estado do Amazonas, Brazil; holotype: UFRJ 5935 [transferred to INPA]). Rivulus duckensis Hrbek, de Deus & Farias, 2004: 571 (Reserva Adolpho Ducke, rivulet emptying into Igarapé Barro Branco, Manaus, Amazonas, Brazil, 2º53 S 59º58 W; holotype: INPA 21444). Killifish genus Rivulus (Rivulidae) from the Brazilian Amazonas river basin Material examined Brazil: Estado do Amazonas: UFRJ 5935, holotype; UFRJ 5936, 1 paratype (c&s); Reserva Ducke, temporary pools near igarapé Acará, lower rio Negro drainage, rio Amazonas basin, Manaus; A. Kirovsky, 22 Feb UFRJ 5937, 1 paratype, (c&s); UFRJ 5938, 1 paratype; same locality and collector, 25 Jan UFRJ 5939, 2 paratypes; same locality and collector, 1 Feb INPA 1850, 2 paratypes; same locality; J. Zuanon, 22 Nov Distinguished from all other congeners by the combination of the following features: anterior portion of trunk slightly wider than deep, jaws short, snout blunt, tip of anal fin rounded in male, caudal fin rounded in male, pelvic-fin tip reaching anterior portion of anal-fin base in male, dorsal-fin origin on vertical between base of 8th and 9th anal-fin rays, dorsal-fin rays 6-7, anal-fin rays 9-10, frontal squamation S-patterned, frontal scales arranged transversely, canal preopercular absent, contact organs on flank scales in male, longitudinal series of scales 32, gill rakers of first branchial arch 1 + 7, transverse black bar through chin, and no black spot on dorsal portion of caudal-fin. Middle rio Amazonas basin (Fig. 23). Habitat Shallow pools in forest (A. Kirovsky, pers. comm.) Fig. 35. Rivulus uatuman, UFRJ 6022, male, holotype, 16.6 mm SL (one day after collection); Brazil: Amazonas: Balbina. Photo by W. J. E. M. Costa. Fig. 36. Brazil: Amazonas: Balbina; temporary swamp within forest, the habitat of Rivulus uatuman. Photo by W. J. E. M. Costa. Rivulus uatuman Costa, 2004 Rivulus uatuman Costa, 2004e: 2 (type locality: Balbina, temporary pool near stream close to Rio Uatumã, rio Amazonas basin, S W, altitude 43 m, Estado do Amazonas, Brazil; holotype: UFRJ 6022). Material examined Brazil: Estado do Amazonas: UFRJ 6022, holotype; UFRJ 6023, 3 paratypes; UFRJ 6024, 2 paratypes (c&s); Balbina, temporary pool near stream close to Rio Uatumã, rio Amazonas basin altitude 43 m); W. J. E. M. Costa, R. Paiva and D. Ramos, 12 Jun Distinguished from all other congeners by the combination of the following features: anterior portion of trunk slightly deeper than wide, jaws short, snout blunt, tip of anal fin rounded in male, caudal fin rounded in male, pelvic-fin tip reaching anterior portion of anal-fin base in male, dorsal-fin origin on vertical through base of the last anal-fin ray or slightly posterior to it, dorsal-fin rays 6-7, anal-fin rays 9-10, frontal squamation S-patterned, frontal scales arranged transversely, canal preopercular absent, contact organs on flank scales in male, longitudinal series of scales 31-33, gill rakers of first branchial arch 1 + 6, longitudinal rows of red dots on flank in male, transverse dark brown bar through the chin, and no distinctive black spot on dorsal portion of caudal fin. Also distinguished from all other species of Owiyeye by having unique colour patterns of unpaired fins in male, consisting of dorsal fin dark grey on basal portion and bright aqua vol. 11 no

29 yellow on distal portion, and caudal fin dark grey with white posterior margin (Fig. 35). Middle rio Amazonas basin (Fig. 23). Habitat Isolated shallow temporary pools within forest, bottom litter, and water dark tea coloured (Fig. 36). Wilson J. E. M. Costa Rivulus uakti Costa, 2004 Rivulus uakti Costa, 2004f: 2 (type locality: São Gabriel da Cachoeira, stream near igarapé Iá, km 9.4 of the road São Gabriel da Cachoeira to Cucuí, upper rio Negro drainage, rio Amazonas basin, S W, altitude 99 m, Estado do Amazonas, Brazil; holotype: UFRJ 5925). Fig. 37. Rivulus uakti, UFRJ 5925, male, holotype, 24.0 mm SL (two days after collection); Brazil: Amazonas: São Gabriel da Cachoeira. Photo by W. J. E. M. Costa. Fig. 38. Rivulus uakti, UFRJ 5926, female, paratype, 27.9 mm SL (two days after collection); Brazil: Amazonas: São Gabriel da Cachoeira. Photo by W. J. E. M. Costa. Fig. 39. Brazil: Amazonas: São Gabriel da Cachoeira; creek at the forest border, the habitat of Rivulus uakti. Photo by W. J. E. M. Costa. Material examined Brazil: Estado do Amazonas: UFRJ 5925, holotype; UFRJ 5926, 36 paratypes; UFRJ 5927, 4 paratypes (c&s); MCP 34858, 2 paratypes; São Gabriel da Cachoeira, stream near igarapé Iá, km 9.4 of the road São Gabriel da Cachoeira to Cucuí, upper rio Negro drainage, rio Amazonas basin; W. J. E. M. Costa, S. Lima and L. Silva, 30 Aug UFRJ 5928, 9; São Gabriel da Cachoeira, upper rio Negro drainage, rio Amazonas basin, stream tributary to igarapé Miuá, km 13.6 of the road São Gabriel da Cachoeira to Cucuí, S W; W. J. E. M. Costa, S. Lima and L. Silva, 30 Aug Distinguished from all other congeners by the combination of the following features: anterior portion of trunk slightly deeper than wide, jaws short, snout blunt, tip of anal fin slightly pointed in male, caudal fin rounded in male, pelvic-fin tip reaching middle of anal-fin base in male, dorsal-fin origin on vertical between base of 8th and 9th analfin rays, dorsal-fin rays 7-8, anal-fin rays 11-12, frontal squamation S-patterned, frontal scales arranged transversely, canal preopercular absent, contact organs on flank scales in male, longitudinal series of scales 32-33, gill rakers of first branchial arch , oblique rows of red dots on flank in male, transverse dark brown bar through the chin, and dark grey to black spot on dorsal portion of caudal-fin in both sexes. Also differs from all other congeners of the Owiyeye in possessing two unique colour patterns: dorsal fin with bright blue distal zone in male, and caudal spot forming a black bar posteriorly bordered by pale yellow bar in female (Figs 37-38). Upper rio Negro basin (Fig. 22). Habitat Moderately sunny places of shallow streams within 159 aqua vol. 11 no

30 Killifish genus Rivulus (Rivulidae) from the Brazilian Amazonas river basin the forest, sandy bottom and reddish hyaline water (Fig. 39). Rivulus amanapira Costa, 2004 Rivulus amanapira Costa, 2004f: 7 (type locality: São Gabriel da Cachoeira, pools near igarapé Fig. 40. Rivulus amanapira, UFRJ 5929, male, holotype, 38.6 mm SL (one day after collection); Brazil: Amazonas: São Gabriel da Cachoeira. Photo by W. J. E. M. Costa. Palestina, Airport road, upper rio Negro drainage, rio Amazonas basin, S W, altitude 110 m, Estado do Amazonas, Brazil; holotype: UFRJ 5929). Material examined Brazil: Estado do Amazonas: UFRJ 5929, holotype; UFRJ 5930, 11 paratypes; UFRJ 5931, 3 paratypes (c&s); MCP 34859, 2 paratypes; São Gabriel da Cachoeira, pools near igarapé Palestina, Airport road, upper rio Negro drainage; W. J. E. M. Costa, S. Lima and L. Silva, 30 Aug Distinguished from all other congeners by the combination of the following features: anterior portion of trunk slightly deeper than wide, jaws short, snout blunt, tip of anal fin slightly pointed in male, caudal fin truncate in male, pelvic-fin tip reaching anterior portion of anal-fin base in male, dorsal-fin origin on vertical between base of 11 th and 13 th analfin rays, dorsal-fin rays 8, anal-fin rays 14-15, frontal squamation S-patterned, frontal scales arranged transversely, canal preopercular absent, contact organs on flank scales in male, longitudinal series of scales 48-49, gill rakers of first branchial arch 1 + 8, longitudinal rows of red dots on flank in male, transverse dark brown bar through the chin, and ovoid dark grey to black spot on dorsal portion of caudal fin in both sexes. Additionally distinguished from all other members of Owiyeye in having entire marginal region of caudal fin bright yellow in male (Fig. 40). Upper rio Negro drainage (Fig. 23). Habitat notes Small shallow temporary pools in the forest, about m in diameter and about 15 cm deep (Fig. 41). Rivulus tecminae Thomerson, Nico & Taphorn, 1992 Fig. 41. Brazil: Amazonas: São Gabriel da Cachoeira; shallow temporary pool within the forest, habitat of Rivulus amanapira. Photo by W. J. E. M. Costa. Rivulus tecminae Thomerson, Nico & Taphorn, 1992: 290 (type locality: open savanna pools about 500 m from left bank, río Guayapo, about 83 km above confluence with río Sipapo, Orinoco basin, Amazonas Federal Territory, Venezuela, 4 16 N W; holotype: MCNG 23886). aqua vol. 11 no

31 Wilson J. E. M. Costa Fig. 42. Jaw suspensorium and opercular apparatus of Rivulus pictus, UFRJ 5959, female, 27.7 mm SL. AA = angulo-articular; DE = dentary; HY = hyomandibula; IO = interopercle; MS = mesopterygoid; MT = metapterygoid; MX = maxilla; OP = opercle; PL = autopalatine; PM = premaxilla; PO = preopercle; QU = quadrate; RA = retro-articular; RC = rostral cartilage; SO = subopercle; SY = sympletic. Arrows indicate: 1 = short and pointed dorsal portion of preopercle (synapomorphy 25.1), diagnostic for Melanorivulus; 2 = vestigial ventral process of the angulo-articular (synapomorphy 18.3), diagnostic for a clade including R. pictus and R. apiamici. Larger stippling indicates cartilage. Scale bar 1 mm. Material examined Venezuela: Território Federal del Amazonas: MCNG 23886, holotype; MCNG 21369, 33 paratypes; open savanna pools about 500 m from left bank, río Guayapo, about 83 km above confluence with río Sipapo, Orinoco basin; L. Nico & E. Guayamare, 28 May Brazil: Estado do Amazonas: UFRJ 2085, 2; UFRJ 2095, 1 (c&s); Inambu, right bank of upper rio Negro; D. Teixeira, 26 Aug Distinguished from all other congeners by the combination of the following features: anterior portion of trunk slightly deeper than wide, jaws short, snout blunt, tip of anal fin rounded in male, caudal fin truncate in male, pelvic-fin tip reaching middle of anal-fin base in male, dorsal-fin origin on vertical between base of 9 th and 10 th anal-fin rays, dorsal-fin rays 8-10, anal-fin rays 12-15, frontal squamation S-patterned, frontal scales arranged transversely, canal preopercular absent, contact organs on flank scales in male, longitudinal series of scales 37-41, gill rakers of first branchial arch 1 + 7, red stripes on flank, transverse black bar through the chin, and vertically elongated dark grey to black spot on dorsal portion of caudal-fin in both sexes. Upper Orinoco river basin, Venezuela, and upper Negro river, Brazil (Fig. 19). Habitat Temporary pools in savannas (D. Teixeira, pers. comm.). Melanorivulus, new subgenus Type species: Rivulus punctatus Boulenger, Distinguished from the remaining subgenera of Rivulus in having the following apomorphic features: dorsal portion of preopercle short and pointed (25.1) (Fig. 42), dorsal and anal fins slightly pointed in male (72.1, 73.1; also occurring in Laimosemion) (Fig. 43), two oblique bars on post-orbital region (97.1) (Fig. 43), melanophores concentrated on margins of unpaired and pelvic fins in female (111.1) (Fig. 44), and female with black spot on 161 aqua vol. 11 no

32 Killifish genus Rivulus (Rivulidae) from the Brazilian Amazonas river basin upper portion of caudal fin not close to fin margin, overlapping caudal fin bars (113.2) (Fig. 44). All included species except R. modestus have oblique chevron-like rows of red dots or bars on flank in males (90.2) (Fig. 43). Etymology From the Latin, melania (black pigmentation on the skin) and rivulus (stream), referring to the black margins of unpaired and pelvic fins, a condition unique among congeners. Gender masculine. Included species Rivulus apiamici Costa, 1989, R. cyanopterus Costa, 2005, R. dapazi Costa, 2005, R. decoratus Costa, 1989, R. egens Costa, 2005, R. litteratus Costa, 2005, R. modestus Costa, 1991, R. paracatuensis Costa, 2003, R. parnaibensis Costa, 2003, R. pictus Costa, 1989, R. pinima Costa, 1989, R. punctatus Boulenger, 1895, R. rossoi Costa, 2005, R. rutilicaudus Costa, 2005, R. scalaris Costa, 2005, R. violaceus Costa, 1991, R. vittatus Costa, 1989, and R. zygonectes Myers, Paraná-Paraguay-Uruguay, upper Tapajós, upper and middle Xingu, upper and middle Tocantins, São Francisco and Parnaíba river basins, in central and north-eastern Brazil, south-eastern Bolivia, Paraguay and northern Argentina. Greatest diversification concentrated in the central Brazilian Plateau (Costa, 2005a). Rivulus modestus Costa, 1991 Rivulus modestus Costa, 1991: 329 (type locality: rio Mutum, rio Tapajós basin, Mato Grosso, Brazil; holotype: MNRJ 11670). Material examined Brazil: Estado de Mato Grosso: MNRJ 11670, holotype; MNRJ 11671, 5 paratypes; UFRJ 2102, 6; UFRJ 2103, 5 (c&s); small stream tributary of rio Mutum, at crossing with road BR-364, 51 km from Vilhena, rio Juruena drainage, rio Tapajós basin; K. Tanizaki, M. T. Lacerda, S. O. Kullander & A. Hogerborn-Kullander, 16 Oct Distinguished from all other congeners by the combination of the following features: anterior portion of trunk deeper than wide, jaws short, snout blunt, tip of anal fin slightly pointed in male, caudal fin rounded in male, pelvic-fin tip reaching anterior portion of anal-fin base in male, dorsal-fin origin on vertical between base of 8th and 9th anal-fin rays, dorsal-fin rays 10-11, anal-fin rays 13-14, frontal squamation F-patterned, frontal scales arranged circularly, canal preopercular absent, contact organs absent, longitudinal series of scales 31-33, gill rakers of first branchial arch , red marks of flank absent, lower jaw black, and round black spot on dorsal portion of caudal-fin in female. Upper rio Juruena drainage (Fig. 10). Habitat notes Shallow creeks with slow current, in moderately sunny region. Rivulus zygonectes Myers, 1927 Rivulus zygonectes Myers, 1927: 127 (type locality: Vereda Extrema, into Cannabrava [now Cana Brava, at rio Tocantins left bank], Goyas [now Estado de Goiás], Brazil; lectotype: CAS 76314, designated by Huber, 1992: 464). Material examined Brazil: Tocantins-Araguaia basin: Estado de Goiás: CAS 76314, lectotype; Vereda Extrema into Cana Brava; C. Ternetz, 14 Jan UFRJ 1575, 3; stream 15 km E of Aruanã; W. J. E. M. Costa et al., 29 Aug UFRJ 1748, 6; stream tributary to rio Verde, 30 km E of São Miguel do Araguaia; W. J. E. M. Costa et al., 25 Aug UFRJ 1567, 5; stream 98 km W of Jussara; W. J. E. M. Costa et al., 30 Aug UFRJ 1482, 22; UFRJ 2108, 2 (c&s); stream tributary to rio Verde, 32 km N of São Miguel do Araguaia; W. J. E. M. Costa et al., 25 Aug MZUSP 35416, 20; MZUSP 38334, 55; pool in Aruanã; W. J. E. M. Costa et al., 28 Jan Estado do Tocantins: UFRJ 2106, 6; UFRJ 2107, 4 (c&s); stream 20 km S of Santa Rosa; W. J. E. M. Costa et al., 15 Feb MZUSP 38375, 2; stream tributary to córrego Dona Francisquinha, Porto Nacional; W. J. E. M. Costa et al., 31 Jan UFRJ 1712, 7; stream tributary to rio Verde, 50 km N of São Miguel do Araguaia; W. J. E. M. Costa et al., 25 Aug UFRJ 1597, 2; stream 12 km N of Sandolândia; W. J. E. M. Costa et al., 27 aqua vol. 11 no

33 Wilson J. E. M. Costa Aug MZUSP 37212, 28 (6 c&s); road between road BR-153 and Formoso do Araguaia, 29 km S of Gurupi; P. S. Santos-Filho, Jun MZUSP 45223, 9; rio Água Fria, road Araguaçu- Barreira do Piqui, 27 km N of Araguaçu; F. C. T. Lima, Feb UFRJ 1374, 13; shallow lagoon 2 km W of rio das Mortes at the road Água Boa-Cocalinhos; W. J. E. M. Costa et al., 20 Feb UNT 555, 5; river at the road BR-153 between Filadelphia and Araguaina; E. L. Beerli, 2 Nov UNT 556, 3; rio Brejão, Araguaina; E. L. Beerli & L, M, Lima, 22 Nov UNT 2045, 1; córrego Gorgulho, Porto Nacional; NEAMB, 14 Sep UNT 2046, 1; córrego Gorgulho, Porto Nacional; NEAMB, 14 Sep UNT 2047, 3; córrego Marimbondo, Tupirantins; NEAMB, 27 Oct UNT 2048, 1; córrego Barreiro, Guaraí; NEAMB, 20 Oct UNT 2049, 2; córrego Gorgulho, Porto Nacional; NEAMB, 14 Sep UNT 2050, 1; córrego Gorgulho, Porto Nacional; NEAMB, 14 Sep UNT 2051, 1; córrego Lageado, Paranã; NEAMB, 22 Mar UNT 2052, 9; córrego Água Suja, Tupirantins; NEAMB, 27 Oct UFRJ 5150, 1; floodplains of left bank of rio Tocantins, about 1200 m from the river margin, SSE Sampaio, S W; G. C. Brasil, 8 Jun Estado do Maranhão: UFRJ 5152, 16; swamp about 500 m from the right margin of rio Tocantins, S W; G. C. Brasil, 8 Jun Rio Xingu basin, Estado de Mato Grosso: UFRJ 1386, 1; stream 67 km N of Paranatinga; W. J. E. M. Costa et al., 10 Feb UFRJ 1173, 5; stream at the road BR-080, 9 km E of São José do Xingu; W. J. E. M. Costa et al., 16 Feb UFRJ 1417, 1; stream at the road BR- 080, 2 km E of São José do Xingu; W. J. E. M. Costa et al., 18 Feb UFRJ 1389, 6; stream at the road BR-080, 41 km E of São José do Xingu; W. J. E. M. Costa et al., 17 Feb UFRJ 1420, 6; stream at the road BR-080, 42 km E of São José do Xingu; W. J. E. M. Costa et al., 17 Feb UFRJ 1392, 7; stream at the road BR-080, 36 km E of São José do Xingu; W. J. E. M. Costa et al., 17 Feb UFRJ 1357, 20; stream at the road Paranatinga-Canarana, 158 km of Paranatinga; W. J. E. M. Costa et al., 12 Feb UFRJ 1414, 20; UFRJ 2109; stream at the road BR-080, 7 km E of rio Xingu margin; W. J. E. M. Costa et al., 16 Feb UFRJ 6265, 1; stream near rio Xingu, Altamira; W. J. E. M. Costa et al., 16 Jun Rio Tapajós basin, Estado de Mato Grosso: MZUSP 45304, 10; upper rio Preto, road Cuiabá-Santarém; N. Menezes et al., 24 Oct MZUSP 45321, 2; stream tributary to rio Preto, road to São Francisco; N. Menezes et al., 24 Oct Distinguished from all other congeners by the combination of the following features: anterior portion of trunk slightly deeper than wide, jaws short, snout blunt, tip of anal fin slightly pointed in male, caudal fin rounded in male, pelvic-fin tip reaching anterior portion of anal-fin base in male, dorsal-fin origin on vertical between base of 8 th and 10 th anal-fin rays, dorsal-fin rays 9-11, anal-fin rays 13-15, frontal squamation F-patterned, frontal scales arranged circularly, canal preopercular absent, contact organs absent, longitudinal series of scales 33-35, gill rakers of first branchial arch , oblique rows of red dots sometimes united forming chevron-like bars on flank in male, lower jaw black, and round black spot on dorsal portion of caudal fin in female. Tocantins, Araguaia, Xingu and Tapajós river basins (Fig. 22). Habitat notes Shallow creeks with slow current, in gallery forest of savanna-like region. Rivulus violaceus Costa, 1991 Rivulus violaceus Costa, 1991: 331 (type locality: rio das Mortes, rio Araguaia-Tocantins basin, Mato Grosso, Brazil; holotype: MNRJ 11672). Material examined Brazil: Estado de Mato Grosso, rio das Mortes basin: MNRJ 11672, holotype; MNRJ 11673, 5 paratypes; UFRJ 2104, 20; rio das Mortes when crossed by BR-163 at km 313; K. Tanizaki, M. T. Lacerda, S. O. Kullander & A. Hogerborn-Kullander, 19 Oct UFRJ 143, 16; UFRJ 2105, 7 (c&s); small stream tributary to rio Perdidos, close to BR-070, about 10 km W of Primavera do Leste; K. Tanizaki, M. T. Lacerda, S. O. Kullander & A. Hogerborn-Kullander, 19 Oct UFRJ 1207, 4; rio Suspiro, 57 km S of Paranatinga; W. J. E. M. Costa, C. P. Bove, R. D. Cunha & C. Muratori, 9 Feb UFRJ 4284, 13; idem; M. Britto, C. Moreira & R. Cunha, 28 Oct UFRJ 4283, 3; stream at the road Primavera do Leste-Para- 163 aqua vol. 11 no

34 Killifish genus Rivulus (Rivulidae) from the Brazilian Amazonas river basin natinga; M. Britto, C. Moreira & R. Cunha, 28 Oct Distinguished from all other congeners by the combination of the following features: anterior portion of trunk slightly deeper than wide, jaws short, snout blunt, tip of anal fin slightly pointed in male, caudal fin rounded in male, pelvic-fin tip reaching urogenital papilla in male, dorsal-fin origin on vertical between base of 8 th and 9 th anal-fin rays, dorsalfin rays 10-11, anal-fin rays 14-15, frontal squamation F-patterned, frontal scales arranged circularly, canal preopercular absent, contact organs absent, longitudinal series of scales 30-32, gill rakers of first branchial arch , oblique chevron-like red bars on flank in male, lower jaw black, and round black spot on dorsal portion of caudal fin in female. Upper rio das Mortes drainage (Fig. 10). Habitat notes Shallow creeks with slow current, in gallery forest of savanna-like region. Rivulus litteratus Costa, 2005 Rivulus sp.: Lacerda, 1989: 25 (Ponte Branca, Rio Araguaia, central Brazil). Rivulus pictus (non Costa): Costa et al., 2003: 143 (misidentification of specimens from Alto Araguaia). Rivulus litteratus Costa, 2005a: 75 (type locality: Município de Alto Araguaia, Córrego do Sapo, upper Rio Araguaia basin, road MT-100, 31 km S of Alto Araguaia, 17º S 53º W, altitude 750 m, Estado de Mato Grosso, Brazil; holotype: UFRJ 5956). Material examined Brazil: Estado de Mato Grosso: Município de Alto Araguaia, upper rio Araguaia basin: UFRJ 5956, holotype; Município de Alto Araguaia, córrego do Sapo, upper rio Araguaia basin, road MT-100, 31 km S of Alto Araguaia; W. J. E. M. Costa, B. B. Costa and C. P. Bove, 14 Jan Distinguished from all other congeners by the combination of the following features: anterior portion of trunk slightly deeper than wide, jaws short, snout blunt, tip of anal fin slightly pointed in male, caudal fin rounded in male, pelvic-fin tip reaching anterior portion of anal-fin base in male, dorsal-fin origin on vertical between base of 7 th 8 th l-fin rays, dorsal-fin rays 9-10, anal-fin rays 13-14, frontal squamation F-patterned, frontal scales arranged circularly, canal preopercular absent, contact organs absent, longitudinal series of scales 31-32, gill rakers of first branchial arch , overlapped red marks of variable shape on flank in male, lower jaw dark grey, and round black spot on dorsal portion of caudal-fin in female. Also distinguished from the Fig. 43. Rivulus litteratus, UFRJ 5956, male, holotype, 26.9 mm SL (one day after collection); Brazil: Mato Grosso: Alto Araguaia. Photo by W. J. E. M. Costa. Fig. 44. Rivulus litteratus, UFRJ 5957, female, paratype, 25.6 mm SL (one day after collection); Brazil: Mato Grosso: Alto Araguaia. Photo by W. J. E. M. Costa. Fig. 45. Brazil: Mato Grosso: Alto Araguaia; savanna creek close to córrego do Sapo, habitat of Rivulus litteratus. Photo by W. J. E. M. Costa. aqua vol. 11 no

35 Wilson J. E. M. Costa remaining species of Melanorivulus by possessing a colour pattern consisting of red marks variable in shape and highly overlapped (Fig. 43). Upper rio Araguaia drainage (Fig. 23). Habitat notes Shallow creeks with slow current, in gallery forest of savanna-like region (Fig. 45). Discussion The present study confirms a weakly supported genus Rivulus containing clades corroborated both by morphological (e.g. Huber 1992, Costa 1998a, the present study) and molecular data (e.g. Murphy et al. 1999, Hrbek & Larson 1999), and recognized as subgenera. No unambiguous, apomorphic morphological condition was found to be shared by all species presently assigned to Rivulus and molecular studies indicate that Rivulus is a paraphyletic assemblage (Murphy et al. 1999, Hrbek & Larson 1999). However, a group comprising all species of Rivulus except the subgenus Rivulus is well supported by morphology, their members having a uniquely derived pattern of arrangement of rostral neuromasts (i.e. transversely placed), and a long neural prezygapophysis in caudal vertebrae as already discussed in former studies (e.g. Costa 1998a), also occurring in Kryptolebias. The subgenus Rivulus, as herein defined, is also corroborated by a molecular analysis (Murphy et al. 1999: 295). In other molecular analyses, R. roloffi is considered to be more closely related to other nominal species of Rivulus than to R. cylindraceus (e.g. Hrbek & Larson 1999). As R. roloffi, which was not accurately examined in the present study (only examined at the field just after collection), have more than half caudal fin scaled and a dark green humeral spot, which constitute two synapomorphies of the subgenus Rivulus, R. roloffi is inserted in this subgenus. Although weakly supported by morphological features, Cynodonichthys as proposed here is also corroborated by molecular data (Murphy et al. 1999: 295). However, some molecular analyses do not support monophyly of this assemblage (e.g. Hrbek & Larson 1999). Further analyses should be conducted in order to test the monophyly of this geographically widespread assemblage. Three species of Cynodonichthys from the Brazilian Amazonas basin were found in collections examined in the present study: R. urophthalmus, R. taeniatus and R. micropus. A fourth species, R. xanthonotus, has been reported for the Brazilian Amazon. However, this species, which seems to be similar to R. urophthalmus, is only known from its poor original description (Ahl 1926), where the type locality is inaccurately described (i.e. Amazon Strom ). Huber (1992) reported that types exhibit an uncommon posteriorly positioned dorsal fin, thus constituting a valid species. No specimen potentially identifiable as R. xanthonotus was examined in the present study. Rivulus urophthalmus was found in an extensive region encompassing the lower Amazonas basin and tributaries, and adjacent coastal areas to East, including Maranhão, the type locality R. auratus. This latter species is therefore considered a synonym of R. urophthalmus, as already proposed by Huber (1992). Rivulus poey was described by Steindachner (1876) based on specimens from Belém. The brief description includes characters congruent with R. urophthalmus, previously described from the same locality. As the types of R. poey are unknown, this highly probable synonymy cannot be confirmed. In order to solve this problem, a neotype from the city of Belém is herein designated for R. poey, becoming a clear synonym of R. urophthalmus, as already proposed by other authors (e.g. Garman 1895, Huber 1991). A geographically widespread species of the central and western Brazilian Amazon is here tentatively identified as R. taeniatus, a species first described from the Colombian Amazon and still poorly known. However, the species collected in some distant points of the Brazilian Amazon also fits well with other nominal species from the Peruvian and Ecuadorian Amazon, such as R. rubrolineatus and R. limoncochae, which possibly are synonyms of R. taeniatus. These species have been distinguished mainly on the basis of the number of rows of red dots on the caudal peduncle (i.e. three or five) (e.g. Huber 1992). However, this character was variable within populations both of R. urophthalmus and R. taeniatus (see descriptions above). Steindachner (1863) described R. micropus based upon a single specimen collected in the rio Negro, Brazilian Amazon. The identity of this species was obscure until publication of photos and new morphological data on the holotype (Huber 1991). Henn (1916) described a similar species, R. compressus, from Manaus, a city at the confluence of rio Negro and rio Solimões, central Brazilian Amazon. At the beginning of the description of R. compressus, Henn (1916: 111) noted that: This may be R. micropus Steidachner, but it seems to differ in the 165 aqua vol. 11 no

36 Killifish genus Rivulus (Rivulidae) from the Brazilian Amazonas river basin more forward position of the dorsal, the longer head, etc.. However, Huber (1992) examined types of both species and concluded that these diagnostic characters are similar in both nominal species. This synonymy follows Costa (2003b), supported by material collected in the type locality region, having pointed snout and posteriorly positioned dorsal fin as observed in holotypes of R. micropus (Huber, 1991: fig. 2) and R. compressus (Henn, 1916: fig. 1). Anablepsoides was first proposed to include only R. atratus (Huber, 1992). However, morphological data (Costa 1998a, the present study) consistently corroborated a clade containing both R. atratus and R. ornatus. This hypothesis has not yet been tested by molecular analyses, since both included species were not simultaneously included in these studies (e.g. Murphy et al. 1999, Hrbek & Larson 1999). Examination of types revealed that R. ornatus and R. obscurus, respectively, refer to the male and female of the same species, thus constituting synonyms (Costa 2003b). Rivulus ornatus has been identified as R. obscurus (e.g. Huber 1992), whereas an undescribed species from Peru has been misidentified as R. ornatus (e.g. Fels & de Rham 1982, Huber 1992). The specimen mentioned by Garman (1895: 139) under the description of R. ornatus, as possibly belonging to another species, is in fact a member of the poeciliid genus Fluviphylax Whitley (Costa 1996, Costa & Le Bail 1999). Benirivulus is erected to R. beniensis, which does not fit with any other subgenus of Rivulus. The present phylogenetic hypothesis indicates that Benirivulus is the sister group to a clade including three subgenera, Laimosemion, Owiyeye, and Melanorivulus, each of them corroborated by both morphological and molecular data. The only species of Benirivulus, R. beniensis, was poorly known until now, and consequently was not included in molecular analyses. Myers (1927b) erected R. beniensis on the basis of specimens collected in the drainage of the Beni- Mamoré drainage, rio Madeira basin, and previously misidentified by Pearson (1925) as R. strigatus. Based on putative minor differences in dorsal-fin origin position, Myers (1927b) recognized two subspecies from distinct localities, R. beniensis beniensis and R. beniensis lacustris. Seegers (1985) described R. bolivianus also from the río Mamoré drainage. Examination of material from distant localities along the rio Madeira basin, including the Mamoré, Beni and Guaporé river drainages, revealed that R. beniensis is a widespread species, indistinguishable from R. beniensis lacustris and R. bolivianus, thus confirming the synonymy proposed by Costa (2003b). Huber (1999) erected Laimosemion to include species of the R. geayi superspecies as proposed by Huber (1992). Molecular studies (Murphy et al. 1999, Hrbek et al. 2004) corroborated monophyly of a group comprising species of the R. geayi superspecies, R. breviceps superspecies, and R. frenatus superspecies, which is in accordance to the present study. Two species of Laimosemion are found in the Brazilian Amazonas river: R. strigatus and R. dibaphus. Rivulus strigatus was described by Regan (1912) based on a single specimen donated by Arnold. This material was obtained from an aquarium fish shipment from the city of Pará (now Belém, capital of Estado do Pará) (Arnold 1913). Huber (1992) mentioned rio da Prata, a tributary of rio Jari, Pará, Brazil, as the true type locality of R. strigatus, based on a misinterpreted citation by von Ihering (1931). The latter author, under a brief diagnosis of R. strigatus, cited: Distribuição: (typo) Amazonas, sem mais indicação além do nome do colleccionador Arnold, mas cujo material provem principalmente do rio da Prata (: (type) Amazonas, without further indication besides the collector name Arnold, but that material mainly originates from rio da Prata) (von Ihering 1931: 263). In fact, von Ihering referred to the río de La Plata basin, from where R. punctatus Boulenger was often misidentified as R. strigatus in the past (e.g. Ringuelet et al. 1967), not to the small rio da Prata in Pará, unknown for most ichthyologists and still almost inaccessible at present. The geographic position of the rio da Prata mentioned by von Ihering may be clarified when examining other parts of his paper. For example, among other localities, he cited the occurrence of Phalloceros caudimaculatus (Hensel) for the rio da Prata, Paraguay (von Ihering 1931: 246). Huber (1992) considered both R. strigatus and R. dibaphus as synonyms of R. geayi, a species first described from Amapá, northern Brazil, but also occurring in the Guianas (e.g. Huber 1991, 1992). According to Huber (1991), the three nominal species would have near type localities, but in fact the type locality of R. geayi is about 480 km and 560 km in a straight line from the type locality of R. strigatus and R. dibaphus, respectively, and type locality of R. strigatus is about 710 km from the type locality of R. dibaphus. Comparison of material of R. strigatus with material from the type locality region of R. geayi revealed that R. strigatus is a distinct and valid species, easily distinguished from R. geayi by having a aqua vol. 11 no

37 Wilson J. E. M. Costa rounded caudal fin in the male (vs. subtruncate) and frontal squamation F-patterned (vs. usually E-patterned). Rivulus dibaphus is also a valid species. Examination of the type material of R. dibaphus and material collected in the type locality region revealed that it may be readily distinguished from R. strigatus and R. geayi by the unique colour pattern on the caudal peduncle in the male (Figs 31-32) and that the frontal squamation is always E-patterned. Owiyeye corresponds to the R. rectocaudatus species group diagnosed by Thomerson et al. (1992) and the R. rectocaudatus superspecies diagnosed by Huber (1992). This clade is well supported both by morphological (the present study) and molecular data (Murphy et al. 1999, Hrbek & Larson 1999, Hrbek et al. 2004). Owiyeye and Anablepsoides share two derived conditions (frontal squamation S-patterned and a transverse stripe through chin), but it is parsimoniously considered to a member of a clade also including Laimosemion and Melanorivulus, mainly diagnosed by the absence of second pharyngobranchial teeth. Seven species of Owiyeye are found in the Brazilian Amazon, all described in recent years: R. romeri, R. kirovskyi, R. uatuman, R. uakti, R. amanapira, and R. tecminae. Rivulus kirovskyi and R. duckensis are identical and were collected at the same locality. Both original descriptions were published in 2004, but the name R. kirovskyi has chronological priority over R. duckensis, since the former was published on 30 April, the latter on 20 August. Melanorivulus corresponds to the R. punctatus superspecies diagnosed by Huber (1992) or the Rivulus punctatus species-complex diagnosed by Costa (1995a). This clade is strongly supported by morphology, and is also corroborated by molecular studies (e.g. Murphy et al. 1999, Hrbek & Larson 1999). It includes four species endemic to the Brazilian Amazonas basin: R. modestus, R. zygonectes, R. violaceus, and R. litteratus. As already noted in previous studies (e.g. Costa 1998a, Murphy et al. 1999, Hrbek & Larson 1999), species of Rivulus endemic to the Amazonas basin do not form a monophyletic assemblage. Species from southern Amazonas tributaries, running on the Brazilian Shield (i.e., belonging to Melanorivulus) are more closely related to species endemic to basins to South and East (i.e., Paraná, Paraguay, São Francisco and Parnaíba river basins). On the other hand, species occurring in northern and western Amazonas tributaries arising from the Andes or the Guyana Shield (i.e., belonging to Cynodonichthys, Laimosemion and Owiyeye) are more closely related to species endemic to the Orinoco and Guianas basin. This is probably a historic consequence of the past isolation of rivers draining the Brazilian Shield before the formation of the present Amazonas basin, as described in geological studies (e.g. Beurlen 1970, Lundberg et al. 1998). Field observation on the habitat of Amazonian species of Rivulus revealed that different lineages occupy distinct kinds of habitat. This is most clear for the clade Benirivulus + Laimosemion + Owiyeye + Melanorivulus, in which members of each genus are found in a particular kind of aquatic environment, thus suggesting divergent specializations during the evolution of the group. In Benirivulus, individuals were collected near the margin of stagnant streams and lakes (about cm deep), with dense aquatic vegetation, at the forest border (Fig. 25). Species of Laimosemion, Owiyeye and Melanorivulus were collected in shallower places (about 5-40 cm). Possibly, the ecological preference noted for Benirivulus is the primitive condition for the clade Benirivulus + Laimosemion + Owiyeye + Melanorivulus, since species of Anablepsoides, the putative sister group to the above mentioned clade, live in similar habitats. Amazonian species of Laimosemion were uniquely found in clear water streams, with moderate current and sandy bottom (Figs 29 and 33). No other species from the Amazonas basin inhabits a similar environment, but R. xiphidius and R. geayi, two species of Laimosemion from Guyana, seem to live in the same environmental conditions (Huber 1979). However, R. agilae, another species of Laimosemion from Guyana, has been reported as living in sunny places (Huber 1979). Only species of Owiyeye were found in extremely shallow temporary pools (about 5-10 cm deep) with tea-coloured water (Figs 36 and 41). Since some species of Owiyeye were uniquely found in temporary pools, they possibly are semiannual fishes. An exception is R. uakti, which inhabit marginal zones of creeks at the forest border (Fig. 39). Species of Melanorivulus are found in sunny creeks (Fig. 45) in savanna-like environments. However, this is not a unique condition among Amazonian Rivulus, since R. urophthalmus, R. taeniatus, and R. micropus are also found in sunny creeks, often near the border of forests (Figs 11, 17 and 20). These conditions are interpreted as independently derived, because Melanoorus and Cynodonichthys are not closely related taxa, and basal rivulids (i.e. basal species of Kryptolebias and Prorivulus) inhabit dark 167 aqua vol. 11 no

38 Killifish genus Rivulus (Rivulidae) from the Brazilian Amazonas river basin forested habitats (Costa 2004a, 2004c, Vermeulen & Hrbek 2005). Acknowledgements Thanks are due to E. Araujo, F. Autran, S. Barrera, D. Belote, C. P. Bove, G. C. Brasil, M. Britto, C. Campinha, B. B. Costa, R. D. Cunha, R. D Arrigo, M. I. Landim, S. M. Q. Lima, C. Moreira, R. Paiva, A. Pinto, D. Ramos, A. Sarraf, K. Tanizaki, E. Vicente, and L. Villa-Verde, for help in collecting trips; to H. Berkenkamp, G. Brasil, H. Britski, J. Carvalho, D. Catania, J. L. Figueiredo, K. Hartel, J. Huber, M. Kottelat, S. Kullander, M. Lacerda, P. Lucinda, N. Menezes, D. Moraes Jr., G. Nunan, O. Oyakawa, L. Parenti, C. Pereira, L. Py-Daniel, U. Römer, J. Sarmiento, D. Taphorn, D. Teixeira, and J. Zuanon, for the loan, exchange, or donation of specimens, or for support during visits to their institutions. Collecting trips were supported by Fundação o Boticário de Proteção à Natureza. This study was funded by CNPq-MCT and FAPERJ. Material was collected with permits /98 and /02 from IBAMA (Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis Ministério do Meio Ambiente, dos Recursos Hídricos e da Amazônia Legal). References ARNOLD, J. P Rivulus strigatus, sp. n. Rgn. Wochenschrift für Aquarien-und Terrarienkunde 10: BERKENKAMP, H. O. &. ETZEL, V Die Rivulus-Arten von Panama 2: Wiederbeschreibung von Rivulus brunneus Meek & Hildebrand, 1913 und Beschreibung von Rivulus birkhahni spec. nov. von Chiquiri Grande, West-Panama. Deutsche Killifisch Gemeinschaft Journal 24: BERKENKAMP, H. O. &. ETZEL, V. 1993a. Die Rivulus-Arten von Panama 3: Rivulus kuelpmanni spec. nov., eine neue Bachlingsart von Punta Peña, West-Panama. Deutsche Killifisch Gemeinschaft Journal 25: BERKENKAMP, H. O. &. ETZEL, V. 1993b. Die Rivulus-Arten von Panama 4: Rivulus frommi spec. nov., eine neue Bachlingsart von El Valle, Zentral-Panama. Deutsche Killifisch Gemeinschaft Journal 25: BERKENKAMP, H. O. &. ETZEL, V Die Rivulus-Arten von Panama 5: Rivulus monikae spec. nov., eine weitere neue Bachlingsart aus den bewaldeten und bergigen Teilen der Provinz Coclé, Zentral-Panama. Deutsche Killifisch Gemeinschaft Journal, 27: 1-7. BERKENKAMP, H. O. &. ETZEL, V Die Rivulus-Arten von Panama 6: Zur Identität von Rivulus montium Hildebrand, 1938 mit der Beschreibung einer neuen Art, Rivulus villwocki spec. nov. Deutsche Killifisch Gemeinschaft Journal 29: BERKENKAMP, H. O. &. ETZEL, V Die Rivulus-Arten von Panama 7: Rivulus wassmanni spec. nov., eine neue Bachlingsart der Rivulus birkhahni-kuelpmanni-gruppe aus der Provinz Bocas del Toro, Nordost-Panamá. Aquaristik Aktuell 1999: BEURLEN, K Geologie von Brasilien. Bornträger, Berlin, 444 pp. BUSSING, W. A Status of the cyprinodontid fish genus Rivulus in Costa Rica, with descriptions of new endemic species. Brenesia 17: COSTA, W. J. E. M Descrição de cinco novas espécies de Rivulus das bacias dos rios Paraná e São Francisco (Cyprinodontiformes, Rivulidae). Revista Brasileira de Zoologia 6: COSTA, W. J. E. M Análise filogenética da família Rivulidae (Cyprinodontiformes, Aplocheiloidei). Revista Brasileira de Biologia 50: COSTA, W. J. E. M. 1991a. Redescrição do gênero Rivulus (Cyprinodontiformes: Rivulidae), com notas sobre R. stellifer e R. compactus e a descrição de duas novas espécies do Brasil central. Revista Brasileira de Biologia 51: Costa, W. J. E. M. 1991b. Description of two new species of the genus Rivulus (Cyprinodontiformes: Rivulidae) from eastern South American coastal plains. Revue Suisse de Zoologie 98: COSTA, W. J. E. M. 1995a. Revision of the Rivulus punctatus species-complex (Cyprinodontiformes: Rivulidae). Ichthyological Exploration of Freshwaters 3: COSTA, W. J. E. M. 1995b. Pearl killifishes the Cynolebiatinae: systematics and biogeography of the neotropical annual fish subfamily. TFH, Neptune City, 128 pp. COSTA, W. J. E. M Relationships, monophyly and three new species of the neotropical miniature poeciliid genus Fluviphylax (Cyprinodontiformes: Cyprinodontoidei). Ichthyological Exploration of Freshwaters 7: COSTA, W. J. E. M. 1998a. Phylogeny and classification of Rivulidae revisited: evolution of annualism and miniaturization in rivulid fishes (Cyprinodontiformes: Aplocheiloidei). Journal of Comparative Biology 3: COSTA, W. J. E. M. 1998b. Phylogeny and classification of the Cyprinodontiformes (Euteleostei: Atherinomorpha): a reappraisal. In: Malabarba, L. R., Reis, R. E., Vari, R. P., Lucena, Z. M. S. & Lucena, C. A. S. (Eds.). Phylogeny and classification of neotropical fishes, Edipucrs, Porto Alegre, pp COSTA, W. J. E. M The neotropical annual fish genus Cynolebias (Cyprinodontiformes: Rivulidae): phylogenetic relationships, taxonomic revision and biogeography. Ichthyological Exploration of Freshwaters 12: COSTA, W. J. E. M. 2003a. Family Rivulidae (South American annual fishes). In: R. E. Reis, Kullander, S. O. & Ferraris, C. J., Jr. (eds) Check list of the freshwater fishes of South and Central America, Edipucrs, Porto Alegre, Pp COSTA, W. J. E. M. 2003b. A new miniature rivuline fish from the upper Negro river basin, northern Brazil (Teleostei, Cyprinodontiformes, Rivulidae). Arquivos do Museu Nacional, Rio de Janeiro 61: COSTA, W. J. E. M. 2003c. Rivulus paracatuensis n. sp. (Cyprinodontiformes: Rivulidae): a new rivuline species aqua vol. 11 no

39 Wilson J. E. M. Costa from the Rio São Francisco basin, Brazil. aqua Journal of Ichthyology and Aquatic Biology 7: COSTA, W. J. E. M. 2004a. Relationships and redescription of Fundulus brasiliensis (Cyprinodontiformes: Rivulidae), with description of a new genus and notes on the classification of the Aplocheiloidei. Ichthyological Exploration of Freshwaters 15: COSTA, W. J. E. M. 2004b. Kryptolebias, a substitute name for Cryptolebias Costa, 2004 and Kryptolebiatinae, a substitute name for Cryptolebiatinae Costa, 2004 (Cyprinodontiformes: Rivulidae). Neotropical Ichthyology 2: COSTA, W. J. E. M. 2004c. A new killifish genus and species from the coastal plains of northeastern Brazil (Teleostei: Cyprinodontiformes: Rivulidae). Zootaxa 642: COSTA, W. J. E. M. 2004d. Rivulus kirovskyi, a new killifish from the central Amazon, Brazil (Cyprinodontiformes: Rivulidae). Neotropical Ichthyology 2: COSTA, W. J. E. M. 2004e. Rivulus uatuman sp. n. (Teleostei: Cyprinodontiformes: Rivulidae): a new miniature killifish from the central Amazon. Zootaxa 696: 1-8. COSTA, W. J. E. M. 2004f. Rivulus uakti sp. n. and R. amanapira sp. n. (Teleostei: Cyprinodontiformes: Rivulidae): two new species from the upper Rio Negro, Brazilian Amazon. Zootaxa 465: COSTA, W. J. E. M. 2004g. Rivulus simplicis n. sp. (Cyprinodontiformes: Rivulidae): a new killifish from the coastal plains of south-eastern Brazil. aqua Journal of Ichthyology and Aquatic Biology 8: COSTA, W. J. E. M. 2005a. Seven new species of the killifish genus Rivulus (Cyprinodontiformes: Rivulidae) from the Paraná, Paraguay and upper Araguaia river basins, central Brazil. Neotropical Ichthyology 3: COSTA, W. J. E. M. 2005b. The Neotropical annual killifish genus Pterolebias Garman (Teleostei: Cyprinodontiformes: Rivulidae): phylogenetic relationships. descriptive morphology, and taxonomic revision. Zootax 1067: COSTA, W. J. E. M. & BRASIL, G. C Description of a new species of Rivulus (Cyprinodontiformes: Rivulidae) from the coastal plains of eastern Brazil. Ichthyological Exploration of Freshwater 1: COSTA, W. J. E. M. & LE BAIL, P.-Y Fluviphylax palikur: a new poeciliid from the rio Oiapoque basin, northern Brazil (Cyprinodontiformes: Cyprinodontoidei), with comments on miniaturization in Fluviphylax and other Neotropical freshwater fishes. Copeia 1999: ETZEL, V. & BERKENKAMP, H. O Die Rivulus-Arten von Panama 1: Untersuchungen zur identität von Rivulus chucunaque Breder, Deutsche Killifisch Gemeinschaft Journal 24: FELS, J. F. & HUBER, J. H Descriptión d une espèce nouvelle de Rivulus du Pérou, R. derhami n. sp. et nouvelle description de R. beniensis Myers, 1927 (Pisces, Cyprinodontidae). Revue Française d Aquariologie 12: FELS, J. F. & DE RHAM, P Récentes collectes de Rivulus (Cyprinodontidés) au Pérou, avec description de six espèces nouvelles, deuxième partie. Revue Française d Aquariologie 8: FELSENSTEIN, J Confidence limits on phylogenies: an approach using the bootstrap. Evolution 39: FOWLER, H. W Freshwater fishes from North-western Colombia. Proceedings of the Academy of Natural Sciencies of Philadelphia 96: GARMAN, S The cyprinodonts. Memoirs of the Museum of Comparative Zoology 19: HENN, A. W IX On various South American poeciliid fishes. Annals of the Carnegie Museum 10: plates. HOEDEMAN, J. J The frontal scalation pattern in some groups of toothcarps (Pisces, Cyprinodontiformes). Bulletin of Aquatic Biology 1: HOEDEMAN, J. J Rivulid fishes of Suriname and other Guyanas, with a preliminary review of the genus Rivulus. Studies on the Fauna of Suriname and Other Guyanas 3: HOEDEMAN, J. J Studies on Cyprinodontiform fishes, 8: Preliminary key to the species and subspecies of the genus Rivulus. Bulletin of Aquatic Biology 2: HRBEK, T., DE DEUS, C. P. & FARIAS, I. P Rivulus duckensisi (Teleostei; Cyprinodontiformes): new species from the Tarumã basin of Manaus, Amazonas, Brazil, and its relationships to other neotropical Rivulidae. Copeia 2004: HRBEK, T. & LARSON, A The diapause in the killifish family Rivulidae (Atherinomorpha, Cyprinodontiformes): a molecular phylogenetic and biogeographic perspective. Evolution 53: HUBER, J. H A propos de quatre nouvelles collections de Rivulus des Guyanes, avec description de Rivulus xiphidius n. sp. et Rivulus amphoreus n. sp. Revue Française d Aquariologie 6: HUBER, J. H Revue des espèces de Rivulus de Guyane française, avec descriptions de Rivulus cladophorus n. sp. et de R. igneus n. sp., et nouvelles descriptions de R. urophthalmus Günther et de R. micropus Steindachner. Revue Française d Aquariologie 18: HUBER, J. H Review of Rivulus: ecobiogeografia - relationships. Cybium, Société Française d Ichtyologie, Paris, pp. HUBER, J. H Updates to the phylogeny and systematics of the Neotropical cyprinodont genus Rivulus and its allied (Cyprinodontiformes: Rivulinae). Cybium 23: KITCHING, I. J., FOREY, P. L., HUMPHRIES, C. J. & WILLIAMS, D. M Cladistics, the theory and practice of parsimony analysis (2nd edition), Oxford University Press, Oxford- New York-Tokyo, 228 pp. LASSO, C., TAPHORN, D. C. & THOMERSON, J. E Rivulus gransabanae, a new species of killifish from Venezuela (Cyprinodontiformes: Rivulidae). Ichthyological Exploration of Freshwaters 2: LUNDBERG, J. G., MARSHALL, L. G., GUERRERO, J., HOR- TON, B., MALABARBA, M. C. S. L. & WESSELINGH, F The stage for Neotropical fish diversification: a history of tropical South American rivers. In: Malabarba, L.R., Reis, R. E., Vari, R. P., Lucena, Z. M. S. & Lucena, 169 aqua vol. 11 no

40 Killifish genus Rivulus (Rivulidae) from the Brazilian Amazonas river basin C. A. S. (Eds.). Phylogeny and classification of neotropical fishes, Edipucrs, Porto Alegre, pp MEEK, S. E The freshwater fishes of Mexico North of the Isthmus of Tchuantepec. Publications of the Field Columbian Museum, Zoology 5: MENEZES, N. A. & WEITZMAN, S. H Two new species of Mimagoniates (Teleostei: Characidae: Glandulocaudinae), their phylogeny and biogeography and a key to glandulocaudin fishes of Brazil and Paraguay. Proceedings of the Biological Society of Washington 103: MURPHY, W. J. & COLLIER, G. E Phylogenetic relationships within the aplocheiloid fish genus Rivulus (Cyprinodontiformes, Rivulidae): Implications for Caribbean and Central American Biogeography. Molecular Biology and Evolution 14: MURPHY, W. J. & COLLIER, G. E A molecular phylogeny for aplocheiloid fishes (Atherinomorpha, Cyprinodontiformes): the role of vicariance and the origins of annualism. Molecular Biology and Evolution 14: MURPHY, W. J., THOMERSON, J. E. & COLLIER, G. E Phylogeny of the neotropical killifish family Rivulidae (Cyprinodontiformes, Aplocheiloidei) inferred from mitochondrial DNA sequences. Molecular and Phylogenetic Evolution 13: MYERS, G. S. 1927a. An analysis of the genera of neotropical killifishes allied to Rivulus. Annals and Magazine of Natural History, ser. 9 19: MYERS, G. S. 1927b. Descriptions of new South American fresh-water fishes collected by Dr. Carl Ternetz. Bulletin of the Museum of Comparative Zoology, Harvard 68: PARENTI, L. R A phylogenetic and biogeographic analysis of cyprinodontiform fishes (Teleostei, Atherinomorpha). Bulletin of the American Museum of Natural History 168: PEARSON, N. E The fishes of the Rio Beni basin, Bolivia, collected by the Mullford Expedition. Indiana University Studies 64: POEY, F Poissons de Cuba, espèces nouvelles. Memorias sobre la Historia Natural de la Isla de Cuba, 2: RAMOS, T. C Tree Gardener (computer program), Version 2.3beta. Univ. São Paulo, São Paulo. REGAN, C. T VI Diagnoses of new Central-American freshwater fishes of the families Cyprinodontidae and Mugilidae. Annals and Magazine of Natural History, ser. 7 19: REGAN, C. T A revision of the poeciliid fishes of the genera Rivulus, Pterolebias, and Cynolebias. Annals and Magazine of Natural History, ser. 8 10: REIS, R. E Revision of the neotropical catfish genus Hoplosternum (Ostariophysi: Siluriformes: Callichthyidae), with the description of two new genera and three new species. Ichthyological Exploration of Freshwaters, 7: RINGUELET, R. A., ARAMBURU, R. H. & ARAMBURU, A Los peces argentinos de agua dulce. Comisión de Investigaciones Científicas de la Provincia de Buenos Aires, La Plata, 602 pp. SEEGERS, L Zur Revision der Rivulus-Arten Südost- Brasiliens, mit einer Neubeschreibung von Rivulus luelingi n. sp. und Rivulus caudomarginatus n. sp. (Pisces: Cyprinodontidae: Rivulinae). Zoologische Beiträge 28: SEEGERS, L Ein neuer Rivulide aus Bolivien: Rivulus bolivianus n. sp. (Pisces: Cyprinodontiformes: Rivulidae). Bonner Zoologische Beitrage 39: STEINDACHNER, F Beiträge zur Kenntniss der Sciaenoiden Brasiliens und der Cyprinodonten Mejicos. Sitzungsberichte der kaiserlichen Akademie der Wissenschaften Classe K. 48: , plates 1-4. SWOFFORD, D. L PAUP*. Phylogenetic analysis using parsimony (*and other methods), Beta version 4.0b2. Sinauer, Sunderland, Massachusetts. TAYLOR, W. R. & VAN DYKE, G. C Revised procedures for staining and clearing small fishes and other vertebrates for bone and cartilage study. Cybium 9: THOMERSON, J. E., BERKENKAMP, H. O. & TAPHORN, D. C. 1991a. Rivulus lyricauda, a new species from the Guyana Shield in eastern Venezuela (Cyprinodontiformes: Rivulidae). Ichthyological Exploration of Freshwaters 1: THOMERSON, J. E., NICO, L. G. & TAPHORN, D. C. 1991b. Rivulus immaculatus, a new killifish from Venezuela (Cyprinodontiformes, Rivulidae). Copeia 1991: THOMERSON, J. E., NICO, L. G. & TAPHORN, D. C Rivulus tecminae, a new killifish from Amazonas Territory, Venezuela (Cyprinodontiformes: Rivulidae). Ichthyological Exploration of Freshwaters 2: THOMERSON, J. E. & TAPHORN, D. C Two new annual killifishes from Amazonas Territory, Venezuela (Cyprinodontiformes: Rivulidae). Ichthyological Exploration of Freshwaters 3: WALLACE, A. R Peixes do Rio Negro/Fishes of the Rio Negro. EDUSP, São Paulo, 517 pp. WEITZMAN, S. H. & WOURMS, J. P South American cyprinodont fishes allied to Cynolebias with the description of a new species of Austrofundulus from Venezuela. Copeia 1967: WIENS, J. J. (ed.) Phylogenetic analysis of morphological data, Smithsonian Institution Press, Washington and London, 220 pp. VERMEULEN, F. B. M. & HRBEK, T Kryptolebias sepia n. sp. (Actinopterygii: Cyprinodontiformes: Rivulidae), a new killifish from the Tapanahony River drainage in southeast Surinam. Zootaxa 928: VERMEULEN, F. B. M. & ISBRÜCKER, I. J. 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41 Wilson J. E. M. Costa Appendix 1 The list below includes material examined, except belonging to species of the Brazilian Amazonas basin, which are listed in the Taxonomic accounts above. Data on material is organized in the following sequence: catalogue number, number of specimens, locality. Abbreviations are: c&s, specimens cleared and stained for bone and cartilage, H, holotype, and P, paratype(s). Institutional acronyms are listed in material and methods. Aplocheilidae: Aplocheilus panchax: UFRJ 3140, 2; UFRJ 3141, 2 (c&s); Indonesia: Sulawesi: Desa Radda. Nothobranchiidae: Scriptaphyosemion guignardi: UFRJ 3883, 8; UFRJ 4110, 4 (c&s); Guinea: Dalaba. Rivulidae: Aphyolebias boticarioi: UFRJ 5986, H; UFRJ 5987, 11 P; UFRJ 5988, 5 P; Brazil: Estado do Acre: Porto Acre. Gnatholebias hoignei: MCNG 1116, 18; Venezuela: Portuguesa: La Trinidad. UFRJ 6116, 6; UFRJ 6117, 5 (c&s); Venezuela: Portuguesa: Papelón. Kryptolebias brasiliensis: UFRJ 3458, 32; UFRJ 3682, 1 (c&s); UFRJ 4603, 2 ex. (c&s); UFRJ 5332, 6 ex. (c&s); Brazil: Rio de Janeiro: Magé. Micromoema xiphophora: MCNG 26440, 20; Venezuela: Amazonas: Isla Ratón. UFRJ 3165, 1 (c&s); aquarium material. Moema apurinan: UFRJ 5980, H; UFRJ 5981, 9 P; UFRJ 5982, 7 P (c&s); Brazil: Estado do Acre: Porto Acre. Neofundulus paraguayensis: UFRJ 3647, 10; UFRJ 3648, 4 (c&s); Brazil: Mato Grosso do Sul, about 70 km NW from de Aquidauana. Pituna compacta: UFRJ 3563, 33; UFRJ 3564, 4 (c&s); Brazil: Tocantins: Barreira do Piqui. Prorivulus auriferus: UFRJ 5932, H; UFRJ 5933, 4P; UFRJ 5934, 3P (c&s); Brazil: Bahia: Valença. Rachovia maculipinnis: MCNG 35565, 2; Venezuela: Portuguesa: Sabaneta. UFRJ 6118, 7; UFRJ 6119, 4 (c&s); Venezuela: Portuguesa: Papelón. R. stellifer: MCNG 25828, 9; Venezuela: Portuguesa: La Capilla. UFRJ 245, 5 (c&s); Venezuela: Cojedes: 1 km N of Caño Benito. Renova oscari: MCNG 35926, 2; Venezuela: Amazonas: Isla Ratón. UFRJ 4606, 3 (c&s): aquarium material. Rivulus amphoreus: UFRJ 3889, 2, UFRJ 4606, 3 (c&s); Surinam: Tafelberg. R. apiamici: MZUSP 39976, H; MZUSP 39977, 3P (c&s); UFRJ 5971, 4; UFRJ 5972, 3 (c&s); Brazil: Mato Grosso do Sul; Bataguaçu. R. bahianus: UFRJ 3167, 44; UFRJ 4602, 2 (c&); UFRJ 277, 1 (c&s); Brazil: Bahia: Busca-Vida. R. brunneus: MZUSP uncatalogued, 10 (2 c&s); Panama: Isla de Barro Colorado. R. chucunaque: USNM , 68 (1c&s); Panama. R. cladophorus: UFRJ 643, 4P (2c&s); Guyana: Fourgassier. R. cryptocallus: UFRJ 359, 3; UFRJ 2126, 1 (c&s); Martinique: Ravine Vilaine. R. cyanopterus: UFRJ 5911, H; UFRJ 5913, 36P; UFRJ 5914, 5P (c&s); Brazil: Mato Grosso: Jaciara. R. cylindraceus: MHNC uncat., 6; Cuba: Zapata. USNM uncat., 1 (c&s); Cuba: La Habana. R. dapazi: UFRJ 5915, H; UFRJ 5916, 3P; UFRJ 5917, 2P (c&s); Brazil: Mato Grosso do Sul: Sonora. R. decoratus: MZUSP 39982, H; MZUSP 39983, 4P; UFRJ 2135, 3 (c&s); Brazil: Bahia: Ibiraba. R. derhami: UFRJ 392, 2 (c&s); Peru: Tingo Maria. R. depressus: UFPB 2213, H; UFPB 1749, 17 (2 c&s); UFRJ 2118, 1 (c&s); Brazil: Bahia: Porto Seguro. R. elongatus: MUSM 336, 6; MZUSP 26211, 3; Peru: Ucayali: Pucallpa. R. egens: UFRJ 5973, H; UFRJ 5974, 17P; UFRJ 5975, 3P (c&s); Brazil: Mato Grosso do Sul: Camapuã. R. erberi: UFRJ 358, 3; Ecuador: Napo: Coca. R. fuscolineatus: USNM , 10P; Costa Rica: Guanacaste: Tilaran. R. geayi: MZUSP uncatalogued Brazil: Amapa: Serra do Navio. R. haraldsiolii: UFRJ 125, 6; UFRJ 6295, 2 (c&s); Brazil: Santa Catarina: Joinville. R. hartii: MCZ 26092, 3; Trinidad: Port of Spain. MZUSP 37204, 3; MZUSP 38472, 2 (c&s); Venezuela: Nueva Esparta: Isla de Margarita. R. hildebrandi: USNM 92958, 1P; Panama: Chiriqui: Boquete. R. holmiae: USNM 66302, 1P; Guiana: Holmia. R. igneus: UFRJ 3888, 6; UFRJ 4595, 2 (c&s); Suriname: Creek Colibri. R. immaculatus: USNM , 2P; Venezuela: Bolivar: Elena de Uairen. R. janeiroensis: UFRJ 5333, 8; UFRJ 130, 2 P (c&s); UFRJ 5416, 7 (c&s); Brazil: Rio de Janeiro: Magé. R. luelingi: UFRJ 161, 8, UFRJ 127, 5 (c&s); Brazil: Santa Catarina: Araquari. R. lungi: ZSM 27825, 15; Brazil: Amapá: rio Flechal. R. nicoi: MCNG 23891, H; MCNG 23892, 1P; MCNG 23893, 1P; Venezuela: Amazonas: río Ventuari floodplains. R. nudiventris: MZUSP 40283, H; MZUSP 40284, 3P; MNRJ 11740, 2P (c&s); Brazil: Espírito Santo: Itapemirim. R. paracatuensis: MCP 29639, H; MCP 29640, 1P; UFRJ 2290, 3P (c&s); Brazil: Minas Gerais: Brasilândia de Minas. R. parnaibensis: MCP 29639, H; UFRJ 4962, 25P; UFRJ 5449, 4P (c&s); Brazil: Piauí: São Dimas. R. pictus: MNRJ 11550, H; MNRJ 11551, 2P; UFRJ 5959, 2 ex. (c&s); Brazil: Distrito Federal: Planaltina. R. pinima: MZUSP 39978, H; MZUSP 39984, 2P; UFRJ 5960, 20; UFRJ 5961, 4 (c&s); Brazil: Goiás: Rio Verde. R. punctatus: UFRJ 975, 9; UFRJ 2110, 4 (c&s); Brazil: Mato Grosso do Sul: Aquidauana. R. rossoi: UFRJ 5976, H; UFRJ 5977, 7P; UFRJ, 5978, 4P (c&s); Brazil: Mato Grosso do Sul: Campo Grande. R. rubrolineatus: MZUSP 26371, 3; MUSM 1465, 6; Peru: Loreto: Jenaro Herrera. R. rutilicaudus: UFRJ 5965, H; UFRJ 5966, 12P; UFRJ 5967, 3P (c&s); Brazil: Goiás: Serranópolis. R. santensis: UFRJ 5441, 11; UFRJ 6294, 5 (c&s); Brazil: São Paulo: Boracéia. R. simplicis: UFRJ 5940, H; UFRJ 5976, 3P; UFRJ 5942, 5P (c&s); Brazil: Rio de Janeiro: Parati. R. scalaris: UFRJ 5968, H; UFRJ 5969, 19P; UFRJ 5970, 4P (c&s); Brazil: Mato Grosso do Sul: Costa Rica. R. stagnatus: UFRJ 3890, 3; UFRJ 4605, 4 (c&s); Suriname: Wageningen. R. tenuis: UFRJ 4600, 4; UFRJ 4601, 2 (c&s); Guatemala: Alta Verapaz: Sebol. R. vittatus: MZUSP 39981, H; MZUSP 39981, 6P; UFRJ 2206, 15; UFRJ 5962, 4 (c&s); Brazil: Goiás: Cachoeira Alta. R. xiphidius: UFRJ 4608, 3 (c&s); Guyana (specimens born in aquarium). Trigonectes rubromarginatus: UFRJ 3553, 13; UFRJ 3554, 3 (c&s); Brazil: Tocantins: Barreira do Piqui. 171 aqua vol. 11 no

42 Killifish genus Rivulus (Rivulidae) from the Brazilian Amazonas river basin Appendix 2 Characters (in brackets) and character states (in parentheses) used to erect the phylogenetic hypothesis among species of Rivulus and other rivulids are listed below, with the respective reference to papers where the character is first described or discussed. of character states among terminal taxa is presented in the data matrix in Appendix 3. Superficial dermal bones and neurocranium [1] Lachrymal (Parenti 1981; Costa 1998a, 1998b) (CI: 1.00; RI: 1.00): (0) flat, posterior rim wide; (1) slightly twisted, posterior rim reduced, bone formed mainly by canal; (2) very twisted and narrow, slender, canal vestigial. [2] Ventral portion of lachrymal (Costa 1998a) (CI: 0.50; RI: 0.66): (0) short; (1) expanded. [3] Dermosphenotic (Costa 2004d): (CI: 1.00; RI: 1.00): (0) present; (1) absent. [4] Vomerine teeth (Costa 1998a) (CI: 0.40; RI: 0.80): (0) usually 1-4, sometimes 5-6; (1) 6-12; (2) teeth absent [not ordered]. [5] Anterior retrorse process of lateral ethmoid (Costa 1990) (CI: 1.00; RI: 1.00): (0) short; (1) moderate to elongate. [6] Lateral process of sphenotic (Costa 2005b) (CI: 0.50; RI: 0.50): (0) narrow; (1) wide. [7] Anterolateral process of parasphenoid (Costa 1998a) (CI: 0.16; RI: 0.78): (0) short, free; (1) long, attached to pterosphenoid. [8] Posterior portion of parasphenoid (Costa 2005b) (CI: 0.50; RI: 0): (0) wide; (1) narrow. [9] Lateral border of frontal (Costa 1998a) (CI: 1.00; RI: 1.00): (0) well-ossified, approximately straight; (1) poorly ossified, concave. Jaws, jaw suspensorium and opercular apparatus [10] General shape of the premaxilla and dentary (Costa 1998a) (CI: 0.25; RI: 0): (0) elongate, snout profile sharply pointed; (1) short, snout profile blunt. [11] General shape of ascending process of premaxilla (modified from Parenti, 1981, Costa 1998b) (CI: 1.00; RI: 1.00): (0) curved, posterior portion medially directed; (1) approximately straight. [12] Ascending process of premaxilla (Costa 2005b) (CI: 0.50; RI: 0): (0) wide; (1) narrow. [13] Ventral process of maxilla (Parenti 1981, Costa 1998a) (CI: 1.00; RI: 1.00): (0) slightly curved, anterior margin rounded; (1) bent, anterior margin triangular. [14] Maxilla (modified from Parenti 1981) (CI: 0.40; RI: 0.72): (0) approximately straight; (1) slightly twisted; (2) greatly twisted. [15] Rostral cartilage (Costa 1998a) (CI: 0.25; RI: 0.40): (0) approximately rounded; state 1: longitudinal length longer than transversal length. [16] Posterior portion of rostral cartilage (Costa 2004a) (CI: 0.20; RI: 0.69): (0) not distinctively narrowed; (1) distinctively narrowed. [17] Coronoid process of dentary (Costa 1998a) (CI: 1.00; RI: 1.00): (0) broad; (1) narrow. [18] Ventral process of angulo-articular (modified from Costa 1990, 1998a) (CI: 0.66, RI: 0.81): (0) large and broad; (1) large, somewhat narrowed; (2) moderate, narrow and pointed; (3) vestigial; (4) long and somewhat narrowed [not ordered]. [19] Curvature of ventral process of angulo-articular (Costa 1998a) (CI: 1.00, RI: 1.00): (0) straight; (1) curved. [20] External medial teeth of premaxilla and dentary (Costa 1998a) (CI: 0.33; RI: 0.50): (0) approximately directed as other teeth; (1) laterally displaced, strongly contrasting to other teeth. [21] Ventral portion of palatine (Costa 1998a) (CI: 1.00; RI: 1.00): (0) long, overlapping dorsal portion of quadrate; state 1: short, not or slightly contacting quadrate. [22] Metapterygoid (modified from Costa 1998a) (CI: 0.66; RI: 0.90): (0) about rectangular, dorsal and ventral portions wide and approximately equal in width; (1) dorsal portion slightly constricted; (2) about triangular, dorsal portion strongly constricted. [23] Posterior process of quadrate (Costa 1998a) (CI: 0.50; RI: 0.50): (0) short, about 50% of quadrate length; (1) long, about 70% of quadrate length. [24] Preopercle (Costa 1990) (CI: 1.00; RI: 1.00): (0) robust, L-shaped, with a well-developed anteromedian rim; (1) thin, C- shaped, with a reduced anteromedian rim. [25] Dorsal arm of preopercle (Costa 1990) (CI: 0.50; RI: 0.85): (0) broad; (1) narrow and pointed. Hyoid and branchial arches [26] Anterior process of urohyal (Costa 1998a) (CI: 1.00; RI: 1.00): (0) short; (1) elongate. [27] Dorsal process of urohyal length (CI: 1.00; RI: 1.00): (0) present; (1) absent; (?) very short to absent. [28] Dorsal process of urohyal length (Costa 1998a) (CI: 0.25; RI: 0.85): (0) short; (1) elongate; (?) process absent. [29] Basihyal (Costa 1998a) (CI: 0.50; RI: 0): (0) shorter than space occupied by basibranchials; (1) longer than space occupied by basibranchials. [30] Basihyal cartilage extent, as percentage of basihyal length (modified from Costa 1998a) (CI: 0.40; RI: 0.62): (0) %; (1) %; (2) %. [31] Interhyal (Parenti 1981) (CI: 1.00; RI: 1.00): (0) ossified; (1) cartilaginous. [32] Interhyal (Costa 2005b) (CI: 1.00; RI: 1.00): (0) large; (1) minute. [33] Number of branchiostegal rays (Costa 2004e) (CI: 0.33; RI: 0): (0) 6; (1) 5. [34] Main axis of first epibranchial (Costa 1998a) (CI: 1.00; RI: 1.00): (0) approximately straight; (1) curved. [35] Subdistal process of second epibranchial (Costa 2004a) (CI: 1.00; RI: 1.00): (0) present; (1) absent. [36] Uncinate process of third epibranchial (modified from Costa 1998a, b) (CI: 1.00; RI: 1.00): (0) long; (1) moderate; (2) short. [37] Interarcual cartilage (modified from Parenti 1981) (CI: 1.00; RI: 1.00): (0) not reduced; (1) reduced (CI: 1.00; RI: 1.00). [38] Number and arrangement of second pharyngobranchial teeth (Costa 2004a) (CI: 0.50; RI: 0.88): (0) numerous teeth arranged in two rows; (1) few teeth arranged in single row; (2) teeth absent [not ordered]. [39] Proximal edge of first hypobranchial (Costa 1998a) (CI: 0.33; RI: 0.33): (0) plain, terminating in single cartilage united to second basibranchial; (1) bifid, terminating in cartilage united to second basibranchial and another smaller cartilage united to first basibranchial. aqua vol. 11 no

43 Wilson J. E. M. Costa [40] Distal edge of first hypobranchial (Costa 2004a) (CI: 1.00; RI: 1.00): (0) articular face restricted to cartilaginous head of first ceratobranchial; (1) articular face anteriorly expanded. [41] Orientation of anterior tip of fifth ceratobranchial (Costa 2005b) (CI: 0.50; RI: 0.50): (0) anterior; (1) anterolateral. Vertebrae and caudal skeleton [42] Pointed, anteriorly directed process on first vertebra (modified from Costa 1990) (CI: 1.00; RI: 1.00): (0) absent; (1) present. [43] Epipleural ribs (Parenti 1981, Costa 1998a) (CI: 0.50; RI: 0.66): (0) rod-like; (1) bifid. [44] Neural prezygapophyses (Costa 1990) (CI: 0.33; RI: 0.84): (0) short; (1) long. [45] Hypurals (modified from Costa 1998a) (CI: 0.42; RI: 0.33): (0) two dorsal plates and one ventral plate separated by gap; (1) two plates separated by wide gap; (2) two plates in close proximity, sometimes ankylosed; (3) single plate. [46] Proximal end of parahypural (Costa 1998b) (CI: 1.00; RI: 1.00): (0) robust with paired dorsal processes overlapping preural centrum; (1) shortened and laminar, without dorsal paired process, not contacting preural centrum. [47] Hemal spine of preural centrum two (Costa 1998b) (CI: 0.50; RI: 0): (0) distinctively wider than hemal spines anterior to it; (1) slightly wider or equal in width to hemal spines anterior to it. [48] Number of vertebrae (modified from Costa 1990) (CI: 0.18; RI: 0.52): (0) 29-32; (1): 33-35; (2) [49] Number of caudal-fin rays (modified from Costa 1990) (CI: 0.18; RI: 0.59): (0) 26-31; (1) 32-36; (2) [not ordered]. Dorsal- and anal-fin skeleton [50] First dorsal-fin ray (modified from Parenti, 1981) (CI: 1.00; RI: 1.00): (0) single long first ray connected to two proximal radials; (1) long fin ray connected to two proximal radials, preceded by one or two short fin rays. [51] Anterior proximal radials of dorsal and anal fins (Costa 2005b) (CI: 1.00; RI: 1.00): (0) slender; (1): wide. [52] Number of anal-fin rays (modified from Costa 1998a) (CI: 0.28; RI: 0.44): (0) 9-15; (1) 16-20; (2) [53] Orientation of anterior proximal radials of anal fin (modified from Costa 1998a) (CI: 1.00; RI: 1.00): (0) anteriorly or dorsally directed; (1) posteriorly directed. Shoulder and pelvic girdle [54] Pectoral-fin insertion (Costa 1998b) (CI: 1.00; RI: 1.00): (0) lateral; (1) ventrolateral. [55] Supracleithrum and posttemporal (modified from Parenti 1981, Costa 1998b) (CI: 0.66; RI: 0.50): (0): separated; (1) co-ossified, limits almost inconspicuous; (2) fused to form a single structure. [56] Keel along supracleithrum-posttemporal (Costa 2005b) (CI: 1.00; RI: 1.00): (0) absent; (1) present. [57] Ventral process of posttemporal (Parenti 1981, Costa 1998a, b) (CI: 0.20; RI: 0.81): (0) present; (1) absent. [58] Posterior flange of cleithrum (Costa 1998a) (CI: 1.00; RI: 1.00): (0) present; (1) absent. [59] First postcleithrum (Parenti 1981) (CI: 1.00; RI: 1.00): (0) present; (1) absent. [60] Fourth pectoral radial (Costa 1998a) (CI: 0.33; RI: 0.75): (0) not expanded; (1) ventrally expanded. [61] Ischial process of pelvic girdle (Costa 2005b) (CI: 1.00; RI: 1.00): (0) prominent; (1) vestigial. [62] Number of pectoral-fin rays (modified from Costa 1998a): (0) 13-15; (1) [63] Number of pelvic-fin rays (Costa 1990) (CI: 1.00; RI: 1.00): (0) six; (1) seven; (2) eight. External morphology of body and head [64] Mouth (Costa 1998b) (CI: 1.00; RI: 1.00): (0) terminal; (1) superior. [65] Orbital rim (modified from Parenti 1981) (CI: 1.00; RI: 1.00): (0) free dorsally, attached ventrally; (1) completely attached. [66] Branchiostegal and opercular membranes (Parenti 1981) (CI: 1.00; RI: 1.00): (0) separated by long fold; (1) continuous. [67] Skin fold on corner of preopercular region (Costa 2005b) (CI: 1.00; RI: 1.00): (0) present; (1) absent. External morphology of fins [68] Pectoral fin (Costa 1990) (CI: 0.50; RI: 0.75): (0) rounded; (1) pointed. [69] Pectoral-fin length (modified from Parenti 1981) (CI: 0.33; RI: 0.75): (0) % SL; (1) % SL. [70] Extent of pelvic fin in males (Costa 1998a) (CI: 0.25; RI: 0.25): (0) short, tip not surpassing anterior portion of anal fin; (1) long, its tip reaching the central or the posterior portion of the anal fin. [71] Pelvic-fin (Costa 2005b) (CI: 1.00; RI: 1.00): (0) bases separated or in contact; (1) bases united; (2) pelvic fins united along proximal portion of medial margin. [72] Dorsal fin (modified from Costa 1998a) (CI: 0.33; RI: 0.84): (0) short, tip rounded; (1) somewhat elongated, tip pointed; (2) long, tip sharply pointed. [73] Anal fin (modified from Costa 1998a) (CI: 0.22; RI: 0.75): (0) short, tip rounded; (1) somewhat elongated, tip pointed; (2) long, tip sharply pointed. [74] Filaments on tip of dorsal and anal fins in males (Costa 1998a) (CI: 0.50; RI: 0.66): (0) absent; (1) present. [75] Filaments on posterior border of caudal fin in males (Costa 1998a) (CI: 0.33; RI: 0.60): (0) absent; (1) present. [76] Caudal-fin length in males (Costa 1990) (CI: 0.40; RI: 0.70): (0) ; (1) ; (2) [77] Caudal-fin shape in males (CI: 0.33; RI: 0.40): (0) rounded; (1) subtruncate; (2) truncate; (3) acuminate [not ordered]. [78] Dorsal and ventral extensions on caudal fin in males (Costa 1998a) (CI: 0.50; RI: 0): (0) absent; (1) present. Squamation [79] General arrangement of frontal scales (Hoedeman 1958) (CI: 0.50; RI: 0.85): (0) transverse; (1) circular; (2) irregular [not ordered]. [80] Predominant frontal squamation-pattern (Hoedeman 1958) (CI: 0.28; RI: 0.52): (0) G; (1) E; (2) D; (3) F; (4) S [not ordered]. [81] Arrangement of E-scales (Costa 1990) (CI: 1.00; RI: 1.00): (0) overlapped; (1) not overlapped. [82] Caudal-fin squamation in older males (Costa 1990, 1998a) (CI: 0.25; RI: 0.57): (0) approximately on anterior % of fin; (1) approximately on 40 % of fin; (2) approximately on % of fin. 173 aqua vol. 11 no

44 Killifish genus Rivulus (Rivulidae) from the Brazilian Amazonas river basin [83] Anal-fin base squamation in males (Costa 2005b) (CI: 1.00; RI: 1.00): (0) no scales on anal-fin base; (1) 1-7 rows of scales on anal-fin base. Laterosensory system [84] Cephalic canals (modified from Parenti 1981) (CI: 0.75; RI: 0.92): (0) anterior and posterior infraorbital, preopercular and posterior mandibular closed, supraorbital, rostral, anterior mandibular open with skin trenches around neuromasts; (1) anterior and posterior infraorbital, and preopercular closed, supraorbital, rostral, anterior and posterior mandibular open with skin trenches around neuromasts; (2) anterior and posterior infraorbital, dorsal preopercular, supraorbital, rostral, anterior and posterior mandibular open with skin trenches around neuromasts; (3) no vestige of canals, all neuromasts completely exposed. [85] Number of anterior supraorbital neuromasts (Costa 1990) (CI: 0.50; RI: 0.33): (0) 3; (1) 4; (2) 6 7. [86] Arrangement of anterior supraorbital neuromasts (Costa 2004d) (CI: 1.00; RI: 1.00): (0) continuous row; (1) posteriormost neuromast separated by space covered by scale. [87] Arrangement of anterior and posterior rostral neuromast (CI: 1.00; RI: 1.00): (0) longitudinal; (1) transverse. Contact organs [88] Contact on flank scales in males (Costa 2005b) (CI: 0.14; RI: 0.66): (0) absent; (1) present. Male colour patterns [89] Red marks on male flank (CI: 0.16; RI: 0.44): (0) absent; (1) present. [90] Kind of red marks on male flank (CI: 0.44; RI: 0.69): (0) vertical rows of dots, sometimes forming stripes; (1) vertical rows of dots on anterior portion, chevron-like bars on posterior; (2) dots on chevron-like series on entire flank, sometimes forming oblique bars; (3) overlapping longitudinal and oblique rows; (4) red marks irregularly arranged, not forming any distinguishable pattern; (?) red marks absent [not ordered]. [91] Dark pigmentation pattern on humeral region (modified from Costa 1998a) (CI: 0.33; RI: 0.50): (0) not distinctively coloured; (1) forming distinct blotch. [92] Dark pigmentation pattern on upper portion of caudalfin base (Costa 2005b) (CI: 0.50; RI: 0.40): (0) not distinctively coloured; (1) forming distinct blotch. [93] Dark pigmentation on anterior half of flank when fish is exposed to sunlight (modified from Costa 1998a) (CI: 0.20; RI: 0.80): (0) not distinctively marked; (1) forming grey vertical bars; (2) forming dark grey broad stripe; (3) forming dark grey oblique bars [not ordered]. [94] Dark pigmentation between dorsum and flank (modified from Costa, 1998a) (CI: 1.00; RI: 1.00): (0) not distinctively marked; (1) forming longitudinal dark zone. [95] Dark pigmentation pattern on iris (Parenti 1981) (CI: 1.00; RI: 1.00): (0) no distinctive mark; (1) bar crossing eye. [96] Pigmentation pattern on suborbital region (Costa 1998a) (CI: 0.66; RI: 0.75): (0) no distinctive mark; (1) grey to black suborbital bar; (2) red suborbital spot [not ordered]. [97] Pigmentation pattern on post-orbital and preopercular region (Costa 1998a) (CI: 0.40; RI: 0.66): (0) no distinctive pattern; (1) two oblique bars; (2) post-orbital vertical bar; (3) two oblique stripes [not ordered]. [98] Dark pigmentation pattern on lower jaw (Costa 2004d) (CI: 0.33; RI: 0.84): (0) not distinctively concentrated; (1) jaw dark grey to black; (2) transverse stripe through chin [not ordered]. [99] Dark blue to dark purplish blue iridescence on opercular and infraorbital region (Costa 1998a) (CI: 0.25; RI: 0.57): (0) absent; (1) present. [100] Dark pigmentation on distal portion of male anal fin (Costa 1998a) (CI: 0.20; RI: 0.50): (0) not distinctive concentrated; (1) concentrated to form stripe. [101] Yellow to orange pigmentation pattern on ventral portion of caudal fin (modified from Costa 1998a) (CI: 0.10; RI: 0.55). (0) not distinctive concentrated; (1) concentrated to form stripe; (?) variable. [102] Yellow to orange pigmentation pattern on dorsal portion of caudal fin (modified from Costa 1998a) (CI: 0.11; RI: 0.50). (0) not distinctive concentrated; (1) concentrated to form stripe; (?) variable. [103] Dark pigmentation of ventral margin of male caudal fin (modified from Costa 1998a) (CI: 0.33; RI: 0.75): (0) not distinctive concentrated; (1) concentrated to form stripe. [104] Red pigmentation pattern on subventral portion of caudal fin (CI: 0.33; RI: 0.66): (0) not distinctive concentrated; (1) concentrated to form stripe. [105] Red pigmentation on caudal fin (modified from Costa 1998a) (CI: 0.33; RI: 0.66): (0) not distinctive arranged; (1) forming bars. [106] Dark pigmentation on dorsal portion of caudal fin (Costa 1998a) (CI: 0.50; RI: 0.75): (0) not distinctive concentrated; (1) concentrated to form dark brown stripe; (?) variable. [107] Melanophore pattern on pectoral fin (Costa 1998a) (CI: 0.33; RI: 0): (0) no distinctive marks; (1) spots; (2) bars [unordered]. [108] Colour of pectoral fin (CI: 0.33; RI: 0.50): (0) hyaline; (1) yellow. Female colour patterns [109] Dark pigmentation pattern on flank and fins (Costa 1998a) (CI: 0.50; RI: 0): (0) forming bars, stripes or spots, according to the pattern occurring in males; (1) flank almost plain, pigmentation reduced to minute dots, not presenting the general pattern as in males. [110] Red marks on flank (CI: 0.25; RI: 0.84): (0) absent; (1) present. [111] Melanophore pattern on unpaired fin margins (Costa 1995a) (CI: 1.00; RI: 1.00): (0) not distinctively concentrated; (1) forming black zones of marginal regions. [112] Dark pigmentation pattern on upper portion of caudalfin base (Costa 1990) (CI: 0.14; RI: 0.71): (0) no distinctive mark; (1) one black spot. [113] Kind of caudal blotch (CI: 0.66; RI: 0.85): (0) black blotch close to fin margin, surrounded by light area to form an ocellate spot; (1) black blotch close to or contacting fin margin, anteriorly bordered by triangular light spot; (2) black blotch apart from fin margin, with light area surrounding anterior, dorsal and posterior margin; (?) caudal blotch absent. aqua vol. 11 no

45 Wilson J. E. M. Costa Appendix 3 Matrix of 113 characters for 49 aplocheiloid species. Characters and states are according to Appendix 2. Autapomorphies were excluded from the analysis; 0 = plesiomorphic state; 1-4 = apomorphic states;? = not pertinent or unknown state A. panchax ? ? S. guignardi ? K. brasiliensis ? ? ? P. auriferus ? ? ? A. boticarioi ? G. hoignei ? ? ? M. xiphophora ? M. apurinan 200? ? N. paraguayensis ? P. compacta ? ? P. longipinnis ?? ? R. maculipinnis ? ? ? R. stellifer ? R. oscari R. amanapira R. amphoreus R. apiamici R. atratus ? ? R. bahianus R. beniensis R. brunneus R. cladophorus ? R. cryptocallus R. cylindraceus R. depressus R. dibaphus ? ? R. hartii R. igneus ? R. janeiroensis ? R. kirovskyi ? R. litteratus R. luelingi R. micropus R. modestus ? R. ornatus ? R. pictus R. punctatus R. romeri ? R. santensis ? ? R. strigatus ? ? R. taeniatus R. tecminae R. tenuis ? R. uakti 201? R. uatuman ? R. urophthalmus R. violaceus R. zygonectes T. rubromarginatus ? 175 aqua vol. 11 no

46 A note from the Editors: As of volume 12, aqua will change its name Fifteen years ago, the idea of publishing a new scientific journal on aquatic biology with a strong focus on fishes was conceived, and in March 1994 the first issue of aqua Journal of Ichthyology and Aquatic Biology saw the light of day. One of the guiding considerations lay in the fact that many fish species and other aquatic animals are primarily distinguished by their colour pattern and a colour photograph of a life specimen may explain more than a thousand words. Still, aquatic biologists did not have adequate access to a scientific journal, which would publish in colour without imposing charges that most authors could not afford. The scientific community enthusiastically welcomed aqua and many of the world s leading ichthyologists submitted their contributions. In response to the ever-increasing number of papers received, aqua increased its output from originally 16 to 48 pages per issue, and from two to six issues per year. With a new Scientific Editor on board, the Managing Editor decided to review the first 12 years of aqua s existence. A total of 168 papers have been published in volumes 1 to 11. Out of these, two papers were on decapod crustaceans, one on ascidians, two on amphibians and reptiles, and two on dolphins. The remaining 161 papers, or 96 % of all contributions, were on fish. Further research revealed that non-ichthyologists perceived aqua as an ichthyological journal, while ichthyologists were not always certain about its profile. As a consequence, we decided to change the name to aqua International Journal of Ichthyology. This change will become effective as of volume 12. Although there are abundant examples of name changes in scientific publishing, any editor would be reluctant to alter the name of a well-established journal. However, we feel it is timely to reflect in a new title what has for a long period been reality on the printed page. You will also find some changes in our Guidelines for Authors, in the journal s layout and in its letter font, all being part of an updated profile of aqua. In our efforts at adapting to constantly changing requirements in the scientific fields covered by aqua, we are supported by the members of our Editorial Board. As of issue 11 (3) a new Board has been formed and we may again draw on the expertise of eminent scientists from various countries, who agreed to make available their expertise in a wide range of specialisations, including emerging fields, such as molecular genetics, which is of increasing importance in fish systematics and phylogeny. We express our gratitude to the members of the outgoing Board for the time and effort they have spent advising us on editorial matters. We warmly welcome the new members and look forward to an inspiring and fruitful cooperation. The changes described here above are part of our continuous efforts at providing the international community of ichthyologists with an efficiently published journal, meeting high scientific and technical standards. We look forward to reading your comments. The Editors Subscription Notice As of volume 12, the subscription rate per volume of aqua (= 4 issues, each issue comprising at least 48 pages) will be: Personal subscription: Euro 75 (including priority mail) Institutional subscription: Euro 140 (including priority mail) In Italy the costs of mail services have increased actually tippled during the last three years and also printing costs have gone up. For these reasons the subscription rates had to be adjusted and we trust that our readership will understand. aqua vol. 11 no

47 1. Manuscript preparation: manuscripts must be submitted in English. In exceptional cases aqua may provide translations of manuscripts written in French, German, Italian, or Spanish. Manuscripts must be word-processed in Microsoft WORD and submitted in an electronic form. Generic, specific, and sub-specific names must be italicised. All papers must conform to the International Code of Zoological Nomenclature. Authors are strongly advised to follow the format set out in previous publications of aqua. 2. Title: the title must be short and should precisely identify the main topic of the article. Names of genera or species are followed by the systematic group to which they belong. Author name(s) are given in full beneath the title, followed by the complete mailing and address(es). 3. Abstract: the abstract should not exceed 250 words and draw attention to the principal conclusions. It should not contain any uncommon abbreviations or literature citations. The inclusion of abstracts in other languages is optional. 5. Subject matter: the text of the manuscript is usually arranged in four main sections: Introduction, Materials and methods (including a key to abbreviations), Results, and Discussion. Other subdivisions may be chosen depending on the material presented. Acknowledgements should be placed between the text and references. Scientific names of genera, species, and subspecies should be followed by the name(s) of author(s) and the year of publication on first mention. A description of a new taxon must contain the following sections: Material,, Description, and Affinities. Holotype and paratypes must be clearly identified, the institution in which they have been deposited named, and the catalogue numbers given. Private collections are not acceptable as repositories for holotypes. Synonyms must be arranged in chronological order. Identification keys must be dichotomous. The metric system and SI units must be used. Temperatures are given in C. Fractions should not be used. 6. References to literature: the name-year system must be used. The list of references should be placed at the end of the paper, alphabetically arranged according to author name. Only those publications cited in the paper may be included. Titles of journals must be given in full. Examples of correct reference formats: Guidelines for Authors BLABER, S. J. M Fish of the Trnity inlet system of North Queensland, with notes on the ecology of fish faunas of tropical Indo-Pacific estuaries. Australian Journal of Marine and Freshwater Research 31: DAY, J. H., BLABER, S. J. M., & WALLACE, J. H Estuarine fishes. In: Estuarine Ecology with Particular Reference to Southern Africa. (Ed. J.H. Day.): A. A. Balkema, Rotterdam. DIMMICH, W. W Ultrastructure of North American cyprinid maxillary barbels. Copeia 1988 (1): TREWAVAS, E Tilapiine Fishes of the Genera Sarotherodon, Oreochromis and Danakilia. British Museum (Natural History), London, 583 pp. 7. Submission of manuscript and illustrations: The manuscript and illustrations must be submitted digitally to the Scientific Editor: Dr. Friedhelm Krupp Senckenberg Research Institute Senckenberganlage Frankfurt am Main, Germany f.krupp@senckenberg.de Tel: , Fax: to whom all subsequent correspondence shall be addressed. Texts, tables, and graphs should be in Microsoft-compatible electronic form. After the paper has been accepted for publication, illustrations as high-resolution TIF files or original photographs (ideally transparencies; otherwise glossy prints, preferably in the size in which they will appear - the type area of aqua is 158 x 224 mm, one column is 76 mm wide) must be sent to: Aquapress, The Managing Editor Via G. Falcone 11, Miradolo Terme (Pavia), Italy aqua@aquapress-bleher.it Authors should retain copies of all materials for reference. Proofs of accepted papers will be sent as PDF files by e- mail attachment to the corresponding author. 8. Evaluation of manuscripts: manuscripts will be evaluated by the editors and referees. Papers are accepted on the understanding that they have not and will not be published elsewhere. 9. Reprints: Authors will receive one free copy of the issue in which their paper appears and an e-print in PDF format. Additional copies may be ordered from Aquapress.

48 aqua Journal of Ichthyology and Aquatic Biology Vol. 11 (4), October 2006 Contents: Wilson J. E. M. Costa: Relationships and taxonomy of the killifish genus Rivulus (Cyprinodontiformes: Aplocheiloidei: Rivulidae) from the Brazilian Amazonas river basin, with notes on historical ecology A note from the Editors Papers appearing in this journal are indexed in: Zoological Record; Biolis Biologische Literatur Information Senckenberg; Cover photo: Rivulus urophthalmus, UFRJ 6264, male, 29.5 mm SL (one day after collection); Brazil: Pará: Altamira. Photo by W. J. E. M. Costa. Brazil: Pará: Primavera; pool close to creek near forest border, typical habitat of Rivulus urophthalmus. Photo by W. J. E. M. Costa.