Zootaxa 1560: 43 53 (2007) www.mapress.com/zootaxa/ Copyright 2007 Magnolia Press ISSN 1175-5326 (print edition) ZOOTAXA ISSN 1175-5334 (online edition) Oligosarcus perdido (Characiformes, Characidae), a new species of freshwater fish from Serra da Bodoquena, upper Rio Paraguai basin, Brazil ALEXANDRE C. RIBEIRO 1,2, MARCEL R. CAVALLARO 2,3 & OTÁVIO FROEHLICH 4 1 Instituto de Biociências, Universidade Estadual Paulista Júlio de Mesquita Filho UNESP. Distrito de Rubião Júnior s/n. 18618-000, Botucatu, SP, Brazil. E-mail: acribeiro@click21.com.br 2 LIRP - Laboratório de Ictiologia de Ribeirão Preto, Departamento de Biologia, FFCLRP, Universidade de São Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirão Preto-SP, Brazil (mailing address). 3 Programa de Pós-Graduação em Biologia Comparada (Doutoramento). Universidade de São Paulo (USP), Depto. de Biologia da FFCLRP, Laboratório de Ictiologia de Ribeirão Preto (LIRP), Avenida dos Bandeirantes, 3900, Ribeirão Preto-SP, 14040-901, Brazil. E-mail: mrcavallaro@gmail.com 4 Universidade Federal de Mato Grosso do Sul, Departamento de Biologia / CCBS, Caixa Postal 549, 79070-900, Campo Grande, MS, Brazil. E-mail: otavio@nin.ufms.br Abstract Oligosarcus perdido, a new species of freshwater fish from Serra da Bodoquena, upper Rio Paraguai basin, Brazil, is described. The new species is distinguished from congeners by the number of lateral-line scales, number of scales around the caudal peduncle, and osteological characters. The osteology of this new species is also documented by stereomicroscopic photography of cleared and stained specimens. Ecological notes based on direct observation by scuba diving in the field are also provided. Key words: Taxonomy, freshwater fishes, Neotropical region Introduction The genus Oligosarcus consists of 16 previously described species (Menezes, 1969a; Menezes, 1987; Miquelarena & Protogino, 1996), distributed throughout most of the main hydrographic systems of cis- Andean South America below 14º of latitude (Menezes, 1988). This wide distributional range includes the Bolivian and Argentinean Andean highlands, the Brazilian crystalline shield, and the Atlantic slope drainages of eastern and southern South America (Menezes, 1988). Species of Oligosarcus are typically small-to medium sized predators on arthropods and other fishes, inhabiting mainly smaller tributaries of the main river basins (Menezes, 1969b; Aranha et. al, 1998; Casatti, 2003; Hermes-Silva et al., 2004). Menezes (1987) provided a comprehensive review of the previous known species and described three new ones. The latest addition to the genus was made by Miquelarena & Protogino (1996) in describing Oligosarcus menezesi. No intraspecific phylogenetic information on this genus has been already provided; however, the presence of tricuspid teeth along most of ectopterygoid length, a unique feature among a set of genera presently assigned as incertae sedis in Characidae (Lima et al, 2003), suggests that the genus consists of a monophyletic group. The phylogenetic relationships and biogeography of Oligosarcus are currently under study by one of the authors (ACR). Recent collecting efforts in the Serra da Bodoquena, a calcareous plateau located at the southern margin of the Pantanal wetland, upper Paraguai basin, Brazil, yielded a new species of Oligosarcus, which is described herein. Accepted by M. R. de Carvalho: 9 Aug 2007; published: 27 Aug. 2007 43
Material and methods Counts and measurements were taken from the left side of specimens with digital calipers and are those described by Fink & Weitzman (1974). All specimen lengths are standard lengths (SL) in mm. Cleared and stained preparations follow the methods of Taylor & Van Dyke (1985). Vertebral counts include the Weberian apparatus as four elements. The terminal half-centrum, hypural bones and associated vertebral elements (PU1+U1) were counted as one vertebra. Counts of gill rakers on the hypobranchial and ceratobranchial of the first branchial arch include one element inserted over the cartilage between the ceratobranchial and epibranchial. All osteological observations, including vertebral counts and number of posteriormost smaller dentary teeth were taken from two cleared and stained specimens. Institutional abbreviations are: MZUSP (Museu de Zoologia da Universidade de São Paulo, São Paulo, Brazil) and LIRP (Laboratório de Ictiologia de Ribeirão Preto, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil). Osteological terminology is mostly from Weitzman (1962), except for the caudal skeleton which follows Weitzman & Fink (1985: page 20, figure. 21), and additional modifications mentioned by Vari & Harold (2001). Abbreviations of bone names used in figures 1 4 are: aa, anguloarticular; ac, anterior ceratohyal; an, antorbital; ba, basihyal; bbr, basibranchial; br, branchiostegal rays; cbr, ceratobranchials; cl, cleithrum; co, coracoid; d, dentary; dh, dorsal hipohyal; ebr, epibranchials; ep, ectopterygoid; epu, epurals; esc, extrascapular; gr, gill rakers; hbr, hypobranchials; hm, hyomandibular; hsp, haemal spine; hy1, hypural 1; hy2, hypural 2; hy3, hypural 3; hy4, hypural 4; hy5, hypural 5; hy6, hypural 6; ih, interhyal; io 1 6, infraorbitals 1 to 6; io, interopercle; lph, lower pharyngeals; m, maxilla; mc, mesocoracoid; msp, mesopterygoid; mtp, metapterygoid; n, nasal; nsp, neural spine; op, opercle; pa, palatine; pc, posterior ceratohyal; phyp, parhypural; pm, premaxilla; pop, preopercle; popc, ossified preopercular canal; ptc1, postcleithrun 1; ptc2, postcleithrun 2; ptc3, postcleithrun 3; ptt, posttemporal; q, quadrate; ra, retroarticular; s, symplectic; sc, scapula; scl, supracleithrum; snp, specialized neural process; sop, subopercle; sph, suspensory pharyngeals; uph, upper pharyngeals; ur, urostyle; urm, uroneural; vh, ventral hypohyal. Oligosarcus perdido, new species Fig.1 Holotype: MZUSP 94691, 97.8 mm SL, bridge over the Rio Perdido, Harmonia farm, municipality area of Porto Murtinho, State of Mato Grosso do Sul, Brazil (21º17 07 S 56º41 45 W), Froehlich, O., Cavallaro, M. R., Pomini, E. & I. S. Escote, 22 October 2005. Paratypes: LIRP 5890, 2, 85.8 91.1 mm SL, collected with holotype. The following tree lots were collected at type locality: LIRP 5891, 1, 80,1 mm SL, Froehlich, O., 09 September 2005; LIRP 5894, 2, 41,5 43,2 mm SL, Froehlich, O., Cavallaro, M. R., Vilela, M. J. A., Almeida, N. V. A., Forster, O. C. & Vargas, R. D., December 2005; LIRP 5896, 5, 39,9 57,7 mm SL, 2 (c&s), 57,7 and 53,4 mm SL, Froehlich, O., Cavallaro, M. R., Vilela, M. J. A., Almeida, N. V. A., Forster, O. C. & Vargas, R. D., December 2005; LIRP 5893, 1, 25,3mm SL, Rio Perdido, upper to its underground section (21º05 42 S/56º48 25 W), municipality area of Bonito, MS, Brazil, Froehlich, O., Cavallaro, M. R., Vilela, M. J. A., Almeida, N. V. A., Forster, O. C. & Vargas, R. D., December 2005. Non type material: LIRP 5474, 1, 33.0 mm SL, bridge over Córrego Seputá, a tributary of Rio Perdido at road MS-382 (21º03 52 S/56º44 27 ), municipality of Bonito, State of Mato Grosso do Sul, Brazil, Castro et al., 30 November 2004. Diagnosis. The new species can be distinguished by the number of lateral-line scales (61 63) from O. argenteus (44 48), O. bolivianus (49 55), O. brevioris (47 55), O. longirostris (47 51), O. macrolepis (44 44 Zootaxa 1560 2007 Magnolia Press RIBEIRO ET AL.
46), O. menesezi (40 48), O. oligolepis (71 81), O. paranensis (47 54), O. pintoi (36 40), O. planaltinae (38 40), O. robustus, (75 85) O. schindleri (45 54), and O. solitarius (48 55). It differs in number of scales around the caudal peduncle (15 20) from O. jenynsi (21 23) and O. hepsetus (23 28). It differs from O. acutirostris by the absence of the enlarged foramen on the premaxila that accommodates the largest dentary tooth when mouth is closed. Description. Morphometrics and meristics in table 1. Body fusiform, completely covered by cycloid scales. Greatest body depth approximately at mid-point between supraoccipital and dorsal-fin origin. Smaller body depth at caudal peduncle. Dorsal profile of head straight from snout tip to posterior terminus of supraoccipital. Slightly convex to almost straight from that point to dorsal-fin origin, between dorsal and adipose fin and slightly concave from adipose fin to caudal-fin base. Ventral profile of body slightly convex from the anteriormost region of dentary tip to pelvic-fin origin, straight from this point to anal-fin origin, slightly convex along anal-fin base, and concave at caudal peduncle (Fig.1). TABLE 1. Morphometics and meristics of Oligosarcus perdido, n. sp. Asterisks indicate data taken from c&s specimens only. Morphometrics Holotype Paratypes Range Mean ± sd. n Standard length (SL) (mm) 97.8 25.3 97.8 13 Percentage of SL Greatest body depth 25.7 23.6 27.3 25.4 ± 1.1 13 Snout to dorsal-fin origin 59.1 56.2 60.9 58.3 ± 1.4 13 Snout to pectoral-fin origin 32.4 31.2 35.3 33.2 ± 1.5 13 Snout to pelvic-fin origin 49.6 48.1 54.2 50.9 ± 2.1 13 Snout to anus 61.7 57.3 63.6 60.9 ± 1.9 13 Snout to anal-fin origin 68.0 63.7 68.8 66.5 ± 1.5 13 Dorsal-fin length 20.2 20.2 25.3 22.2 ± 1.6 13 Dorsal-fin base length 11.3 10.6 13.2 11.7 ± 0.8 13 Posterior terminus of dorsal-fin base to adipose fin 20.5 18.9 22.3 20.5 ± 1.0 13 Posterior terminus of dorsal-fin base to caudal-fin base 34.9 30.7 36.6 34.0 ± 1.5 13 Anal-fin base length 23.8 22.1 26.3 24.3 ± 1.3 13 Anal-fin length 15.9 15.4 21.3 18.2 ± 1.8 13 Caudal peduncle length 12.3 10.1 13.4 11.7 ± 1.0 13 Pectoral-fin length 18.9 15.4 19.1 18.0 ± 1.1 12 Pelvic-fin length 14.9 13.7 15.7 14.6 ± 0.6 12 Caudal peduncle depth 8.7 8.3 10.0 9.0 ± 0.5 13 Head length 31.4 29.0 35.0 31.4 ± 1.4 13 Percentage of head length Snout length 28.7 27.9 31.3 27.8 ± 5.8 13 Orbital diameter 28.5 27.1 31.3 29.1 ± 1.3 13 Postorbital head length 43.5 37.8 45.2 42.0 ± 2.2 13 Interorbital width 20.1 20.1 24.3 21.6 ± 1.1 13 Head height 66.1 61.0 72.6 67.2 ± 3.2 13 Maxilla length 39.9 35.4 53.9 41.8 ± 4.8 13 to be continued. A NEW OLIGOSARCUS (CHARACIDAE) Zootaxa 1560 2007 Magnolia Press 45
TABLE 1. (continued) Meristics Holotype Paratypes Range Mode n Lateral line scales 63 61 63 63 12 Scale rows above lateral line 10 7 11 10 13 Scale rows below lateral line 7 6 8 7 10 Scale rows around caudal peduncle 20 18 21 18 11 Predorsal scales 25 23 33 30 12 Dorsal-fin rays ii9 ii9 ii9 13 Anal-fin rays v25 iv v18 26 v25 13 Pectoral-fin rays i14 i13 i15 i14 12 Pelvic-fin rays i7 i7 i7 12 Premaxilary teeth 8 6 8 7 13 Maxilary teeth 23 19 24 21 13 Anteriormost larger dentary teeth 4 4 4 13 Posteriormost smaller dentary teeth* 14 14 14 2 Gill rakers on epibranchial of firsth branchial arch 8 7 8 8 13 Gill rakers on hypobranchial and ceratobranchial of firsth 14 14 17 14 13 branchial arch Vertebrae* 39 39 39 2 FIGURE 1. A) Oligosarcus perdido. Holotype, MZUSP 94691, 97.8 mm SL, left lateral view. B) Oligosarcus perdido, c&s specimen, paratype LIRP 5896, 53.4 mm SL, right lateral view. 46 Zootaxa 1560 2007 Magnolia Press RIBEIRO ET AL.
FIGURE 2. Infraorbital series (A). Upper jaw (B) and suspensoriun (C) of Oligosarcus perdido. Paratype LIRP 5896, 53.4 mm SL. All right lateral views. Head triangular in lateral view with laterally placed eyes. Mouth terminal with flat anterior profile. Premaxilla overlapping dentary when mouth is closed. Nares located immediately anteriorly to eyes. Adpressed pectoral fin reaching to or extending slightly beyond the origin of pelvic fin in larger specimens and distinctly short in specimens smaller then 40 mm SL. Adpressed pelvic fin extending posteriorly to anus, but not reaching origin of anal-fin. Dorsal fin inserted at vertical located posteriorly to pelvic-fin origin, just anterior to anus. Origin of anal-fin at vertical located at posterior terminus of dorsal-fin base. Orbital ring consisting of six infraorbitals with third infraorbital much bigger than remaining elements (Fig.2A). Anterior orbital margins formed by lateral ethmoid; superior orbital margin formed by frontal; supraorbital absent. Antorbital lying immediately anterior to lateral ethmoid. Mesethmoid pointed anteriorly, contacting frontals immediately posterior to the posterior tip of nasals. Well-developed frontal and parietal fontanelles. A NEW OLIGOSARCUS (CHARACIDAE) Zootaxa 1560 2007 Magnolia Press 47
FIGURE 3. Hyoid arch in left lateral view (A). Complete branchial skeleton in dorsal view (B). Detail of lower pharyngeals in dorsal view (C) and upper pharyngeals in ventral view (D) of Oligosarcus perdido, paratype LIRP 5896, 53.4 mm SL. 48 Zootaxa 1560 2007 Magnolia Press RIBEIRO ET AL.
Premaxilla boomerang-shaped, having a single row of conical teeth (Fig.2B). Some teeth with vestigial cusps. First and sixth tooth bigger than remaining premaxillary teeth. Anterior border of the elongate nasal bone extending over posterior border of premaxilla. Maxilla narrow anteriorly and wide posteriorly (Fig.2B). Tip of anterior maxillary process bulbous. Maxillary with conical to slightly tricuspid teeth with about same size throughout. Dentary narrow anteriorly and wide posteriorly (Fig.2C). Dentary with four larger anteriormost conical teeth, followed by much smaller posterior teeth, which decrease in size gradually and varying in shape from slightly tricuspid to conical. Anguloarticular forked, with a long forward extension lying against the medial surface of dentary and a short extension, projected upward and slightly forward, which delineates the posterior margin of mandible. Retroarticular small and trapezoid-shaped, located over posterior corner of anguloarticular. Palatine small, cartilaginous anteriorly, reaching the second ectopterigoid tooth posteriorly (Fig.2C). Ectopterygoid with slightly tricuspid to conical teeth (Fig.2C). Ectopterygoid dentition extending posteriorly to slightly anterior to a vertical at last dentary tooth. Posterior terminus of ectopterygoid overlapping antero-superior process of quadrate. Mesopterigoid extending from a vertical through third ectoperigoid tooth to immediately anterior to metapterigoid channel (Fig.2C). Major mesopterigoid depth at its posterior portion. Metapterygoid strangulated at mid-point in the region of the metapterigoid canal (Fig.2C). Posterodorsal margin of metapterigoid projecting over anterior hyomandibular margin along its whole extension. Metapterygoid articulation with quadrate immediately ventral to posterior notch of metapterygoid. Anterior, upward projecting extension of quadrate wider then the posterior, horizontal extension. Symplectic elongated. Broad cartilaginous contacts between suspensorial elements. (Fig.2C). Hyomandibular wide dorsally, narrow ventrally, with a cartilaginous area of contact with skull along its antero-dorsal corner (Fig.2C). Hyomandibular articulates with skull via both sphenotic (anteriorly) and pterotic (posteriorly). Preopercle L shaped, wider at ventral region (Fig.2C). Preopercular canal ossified at dorsal aspect of preopercle. Interopercle ellipsoid, slightly wider posteriorly. Opercle longer on dorso-ventral axis, with straight anterior outline, and posterior outline slightly convex ventrally and concave dorsally (Fig.2C). Hyoid arch supporting four branchiostegal rays; three at anterior ceratohyal and one at posterior ceratohyal (Fig.3A). Dorsal hypohyal slightly smaller than ventral hypohyal. Anterior ceratohyal very narrow at mid-point and much wider posteriorly than anteriorly. Interhyal connected at posterodorsal corner of posterior ceratohyal (Fig.3A). Hyoid arch elements connected to each other by broad cartilages (Fig.3A). Branchial arch floor composed of four basibranchials and interconnecting cartilages (Fig.3B). Three large hypobranchials between three anteriormost basibranchials and ceratobranchials. Fourth and fifth ceratobranchials connected to basibranchials via broad cartilages. Well-developed tooth plates on fifth ceratobranchial (Fig.3C). Upper pharyngeal teeth below and anterior to the fourth epibranchial (Fig.3D). Three suspensory pharyngeals attaching branchial arches to skull (Fig.3D). Coracoid, cleithrum, supracleithrum and posttemporal aligned in a C -shaped outline (Fig.4A). Postcleithrum 1 located immediately posterior to the overlapping area between supracleithrum and cleithrum. Postcleithrum 2 and 3 at posteroventral corner of cleithrum. Broad cartilaginous contact between cleithrum, scapula, coracoid and mesocoracoid (Fig.4B). Scapular and coracoid foramen well-developed. Seven supraneurals anterior to dorsal-fin insertion. Dorsal-fin insertion at a vertical between pelvic and anal-fins, between neural spines of 13 th to 21 st vertebrae. Pelvic-fin insertion about half of distance between pectoral and anal-fin bases, between the third and seventh pleural rib. Adpressed pelvic fin not reaching analfin base. Anal fin inserted between haemal spines of the 20 th and 32 nd vertebrae. A NEW OLIGOSARCUS (CHARACIDAE) Zootaxa 1560 2007 Magnolia Press 49
FIGURE 4. Pectoral girdle in right lateral (A), mesial (B), and left lateral view of the caudal skeleton of Oligosarcus perdido. Paratype LIRP 5896, 53.4 mm SL. 50 Zootaxa 1560 2007 Magnolia Press RIBEIRO ET AL.
Upper caudal-fin procurrent rays inserted posterior to the 32 nd vertebra. Lower procurrent rays inserted porterior to 33 rd vertebra. Dorsal caudal-fin lobe with two epurals, one unoreural and four hypurals (3 6). Ventral caudal-fin lobe with two hypurals (1 2). Urostyle forked, with anterior process longer than posterior one (Fig.4C). Color in alcohol. Background color yellowish to tan. Conspicuous triangular-shaped humeral spot. Flank crossed by a dark lateral stripe extending posteriorly from humeral spot, where it is more diffuse, to caudal-fin membrane. Lateral stripe enlarged at the caudal-peduncle. A dark dorsal stripe extending from tip of supraoccipital to caudal-fin base. Scales of dorsal flanks dark pigmented below lateral strip, increasingly more pigmented towards dorsum. Flank below lateral strip almost unpigmented. Fins mostly hyaline. Dark-pigmented caudal-fin membrane between the five central-most caudal-fin rays. Membrane of dorsal and pelvic fins with dark chromatophores along anterior margins of fin rays. Distribution. Know only from the Rio Perdido, a tributary of Rio Apa, in the upper Paraguai basin (Fig. 5) and one of its tributaries, the Seputá stream. FIGURE 5. Map showing the type locality of Oligorsarcus perdido. Ecological notes. The upper part of the Rio Perdido is situated on a carbonate plateau of about 68 km long located at the southern margin of the Brazilian Pantanal Wetland denominated Serra da Bodoquena (Bodoquena Ridge). This river drains a carstic region and has a 2 to 3 km long underground section. In the plateau, the river is dammed by calcareous tufa deposits, which form 1 to 6 meter tall sequences of waterfalls. The dammed section can be as deep as 12 meters, with vertical rock banks and very slow flow. The substrate has many logs, branches and whole trees lying on whitish calcareous clay. During the rainy season, the augmented flow disturbs the clay and the water transparency, which is usually great, is significantly reduced. Specimens were collected in stretches with sluggish to still waters. Underwater observations were made while collecting, for a total of some 20 hours of scuba diving by two of the authors (MRC and OF) and two helpers. The species seems to be present in low densities, with only a few adult individuals observed at any A NEW OLIGOSARCUS (CHARACIDAE) Zootaxa 1560 2007 Magnolia Press 51
time. Active adult individuals were observed from dusk to around 21:00, from near the surface to a depth of 2 meters, and always alone. After this time they could be seen resting along the vertical rocky banks. During daylight hours they remain hidden and were not seen. Young specimens, at least up to 50 mm SL, were observed in activity during the day on two occasions, in small groups (5 6), mingled with schools of Jupiaba acanthogaster (Characiformes: Characidae). Etymology. The specific epithet perdido is Portuguese for lost. This is the name of the river basin where the new species was collected. It is a noun in apposition. Comparative material. Oligosarcus acutirostris, MZUSP 27573, Paratype, 1 (c&s), Brasil, Espírito Santo, Rio São José das torres, road BR- 101 between Campos and Cacheiro do Itapemirim. Oligosarcus argenteus, MZUSP 36584, 2 (c&s), SL, Brasil, Minas Gerais, Viçosa, lake at the Universidade Federal de Viçosa. Oligosarcus bolivianus, MZUSP 26386, 01 exe. Bolívia, Tarija, Rio Tomolosa. Oligosarcus brevioris, MZUSP 36489, Parataype, 1 (c&s), Brasil, Rio Grande do Sul, Vacaria, Arroio Cachoeirinha, Rio Pelotas basin, road between Vacaria end Bom Jesus. Oligosarcus hepsetus MZUSP 53493, 2(c&s) Brasil, São Paulo, Jacupiranga, stream at road BR-116, Km 470, near Jacupiranga. Oligosarcus jenynsii, MZUSP 42370, 2(c&s), Argentina, Buenos Aires, Laguna dos Lobos. Oligosarcus longirostris, MZUSP 35957, 1(c&s), Brasil, Paraná, Rio Piraquara, Rio Iguaçu basin. Oligosarcus macrolepis, MZUSP 37255, 2(c&s), Brasil, Minas Gerais, marginal lagoon of Rio Jequitinhonha, road between Salto da Divisa Jacinto. Oligosarcus menezesi MZUSP 48130, Argentina, Buenos Aires, Laguna del Monte Província. Oligosarcus oligolepis, MZUSP 42368, 2(c&s), Argentina, Buenos Aires, Berisso Los Talas. Oligosarcus paranensis MZUSP 25833, 2(c&s). Brasil, São Paulo, município de Salesópolis, Rio Paraitinga, tributário do rio Tietê, road between Salesópolis a Caraguatatuba. Oligosarcus planaltinae, MZUSP 38083, 2(c&s), Brasil, Brasília, córrego Taboca, Ri São Bartolomeu basin. Oligosarcus pintoi, LIRP 1605, Brasil, São Paulo, Teodoro Sampaio, Córrego São Paulo, Morro do Diabo Park, Rio Paraná basin. Oligosarcus robustus, MZUSP 19876, 2(c&s), Brasil, Rio Grande do Sul, Belém Novo, Arroio Chapéu Virado. Oligosarcus schindleri, MZUSP 27923, 2(c&s), Bolívia, Represa México, 17 km, south of Cochabamba. Oligosarcus solitarius, MZUSP 36644, 2(c&s), Brasil, Minas Gerais, Lago Carioca, Rio Doce basin. Acknowledgments This paper was improved by the suggestions, criticisms and review of Naércio Menezes. We thank Emanuele Pomini, Ismael Escote, Maria José Alencar Vilela, Nereida Vilalba Alvares de Almeida, Ottilie Caroline Forster, and Renata Daniella Vargas for helping in the field during collecting efforts. This project was partially financed by IBAMA (Brazilian Institute for the Environment and Renewable Resources) that provided founding for field trip and FAPESP (Grant 04/09219-6) that provided chemical reagents used in preparing c&s specimens. The authors are financially supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, grants 140488/2004-9 to ACR and 142451/2006-1 to MRC) and Fundação de Amparo à pesquisa do Estado de São Paulo, (FAPESP, grants 06/54407-0 to MRC). References Aranha, J.M.R., Takeuti, D.F. & Yoshimura T.M. (1998) Habitat use and food partitioning of the fishes in a coastal stream of Atlantic Forest, Brazil. Revista de Biologia Tropical, 46 (4), 951 959. Casatti, L. (2003) Alimentação dos peixes em um riacho de parque estadual Morro do Diabo, Bacia do alto Rio Paraná, Sudeste do Brasil. Biota Neotropica, 2 (2), 1 14. Hermes-Silva, S., Meurer, S. & Zaniboni-Filho E. (2004) Biologia alimentar e reprodutiva do peixe-cachorro (Oligosarcus jenynsii Günther, 1864) na região do alto rio Uruguai Brasil. Acta Scientiarum, Biological Sciences, 26 (2), 175 179. 52 Zootaxa 1560 2007 Magnolia Press RIBEIRO ET AL.
Fink, W.L. & Weitzman S.H. (1974) The so-called cheirodontin fishes of Central America with descriptions of two new species (Pisces: Characidae). Smithsonian Contributions to Zoology, no. 172, i iii + 1 46. Lima, F.C.T., Malabarba, L.R., Buckup, P.A., Silva, J.F.P, Vari, R.P., Harold, A., Benine, R., Oyakawa, O.T., Pavanelli C.S., Menezes N.A., Lucena, C.A.S., Malabarba, M.C.S.L., Lucena, Z.M.S., Reis, R.E., Langeani, F., Cassati, L., Bertaco, V.A., Moreira, C. & Lucinda P.H.F. (2003) Genera Incertae Sedis in Characidae. Pp. 106 169 In: R.E. Reis, S.O. Kullander & C. J. Ferraris, Jr. (Eds). Check list of the freshwater fishes of South and Central America. Porto Alegre, Edipucrs, 729p. Menezes, N.A. (1969a). Systematics and evolution of the tribe Acestrohynchini (Pisces: Characidae). Arquivos de Zoologia, São Paulo, 18(1 2): 1 150. Menezes, N.A. (1969b). The food of Brycon and three closely related genera of the tribe Acestrorhynchini. Papéis Avulsos de Zoologia, São Paulo, 22, 217 223. Menezes, N.A. (1987) Três espécies novas de Oligosarcus Günther, 1864 e redefinição taxonômica das demais espécies do gênero (Osteichthyes, Teleostei, Characidae). Boletim de Zoologia, São Paulo, 11, 1 39. Menezes N.A. (1988) Implications of the distribution patterns of the species of Oligosarcus (Teleostei; Characidae) from central and southern South America. Pp. 295 304 In: W.R. Heyers & P.E. Vanzolini (Eds.). Proceedings of a Workshop on Neotropical Distribution Patterns. Rio de Janeiro, Academia Brasileira de Ciências, 488p. Miquelarena, A.M. & Protogino, L.C. (1996) Una nueva especie de Oligosarcus (Teleostei, Characidae) de la cuenca del Río Paraná, Misiones, Argentina. Iheringia, Série Zoologia, Porto Alegre, no. 80, 111 116. Taylor, W.R. & Van Dyke, G.C. (1985) Revised procedures for staining and clearing small fishes and other vertebrates for bone and cartilage. Cybium, 9(2), 107 119. Vari, R.P. & Harold, A.S. (2001) Phylogenetic study of the Neotropical fish genera Creagrutus Günther and Piabina Reinhardt (Teleostei: Ostariophysi: Characiformes), with a revision of the cis-andean species. Smithsonian Contributions to Zoology, 613, 1 239. Weitzman, S.H. (1962) The osteology of Brycon meeki, a generalized characid fish, with an osteological definition of the family. Stanford Ichthyological Bulletin 8, 1 77. Weitzman, S.H. & Fink, S. (1985) Xenurobryconin phylogeny and putative pheromone pumps in Glandulocaudinae fishes (Teleostei: Characidae). Smithsonian Contributions to Zoology, 421, 1 121. A NEW OLIGOSARCUS (CHARACIDAE) Zootaxa 1560 2007 Magnolia Press 53