A new species of the genus Nothobranchius (Cyprinodontiformes: Nothobranchiidae) from the Luapula River basin, Zambia

Size: px

Start display at page:

Download "A new species of the genus Nothobranchius (Cyprinodontiformes: Nothobranchiidae) from the Luapula River basin, Zambia"

Christal Lambert
5 years ago
Views:

1 aqua, Journal of Ichthyology and Aquatic Biology A new species of the genus Nothobranchius (Cyprinodontiformes: Nothobranchiidae) from the Luapula River basin, Zambia Stefano Valdesalici 1 and Rudolf H. Wildekamp 2 1) Via Cà Bertacchi 5,42030 Viano (RE), Italy. valdekil@tin.it 2) Royal Museum of Central Africa, Vertebrate Section, 3080 Tervuren, Belgium. rwildekamp@wanadoo.nl Accepted: Keywords Nothobranchiidae, Nothobranchius rosenstocki, new species, Killifish, Luapula/Bangweulu basin, Zambia Abstract Specimens of three different populations of a Nothobranchius species, collected from ephemeral pools in the Luapula/Bangweulu catchment in Zambia, are considered to be one species on the basis of the coloration of males. The new species has been compared with the Nothobranchius species now known to exist in the same river system. It differs in some morphological features from the other species of Nothobranchius in the same river system and has a distinct colour pattern. Information on its present known distribution is given, as well as on its relationship to the other Nothobranchius species in Zambia and in the adjacent region of the Democratic Republic of Congo. Zusammenfassung Die Exemplare von drei Nothobranchius-Populationen, die in zeitweise ausgetrockneten Tümpeln im Bereich Luapula/Bangweulu in Sambia gesammelt wurden, werden aufgrund der Farbmerkmale der Männchen in einer neuen Art zusammengefasst. Diese wird mit den Nothobranchius-Arten verglichen, die man bisher aus demselben Flusssystem kennt. Zur Unterscheidung werden bestimmte Körper- und Farbmerkmale genannt. Ergänzende Informationen über die gegenwärtig bekannte Verbreitung und die Verwandtschaft zu anderen Nothobranchius-Arten in Sambia und benachbarten Gebieten der Demokratischen Republik Kongo werden genannt. Résumé Des spécimens de trois populations différentes d une espèce de Nothobranchius, collectés dans des mares temporaires, dans le bassin due Lupula/Bangweulu, en Zambie, sont sensés appartenir à une seule espèce, compte tenu de la coloration des mâles. La nouvelle espèce a été comparée aux espèces de Notobranchius actuellement connues dans le même système de rivières. Elle se distingue, par certains traits morphologiques, des autres espèces de Nothobranchius de la même rivière, et par un patron de coloration différent. Des informations sont fournies sur sa distribution connue à ce jour ainsi que sur les liens de parenté avec le sautres espèces de Nothobranchius de Zambie et dans la région limitrophe de la République Démocratique du Congo. Sommario Esemplari di tre diverse popolazioni di specie di Nothobranchius, presi da pozze temporanee di acque di raccolta del bacino Luapula/Bangweulu in Zambia, sono considerati appartenere ad una sola, nuova specie sulla base della colorazione degli individui maschi. Essa è stata confrontata con le altre specie del genere Nothobranchius che sono note abitare lo stesso bacino fluviale. Da queste differisce per alcune caratteristiche morfologiche e possiede una colorazione distinta. Vengono date informazione sulla distribuzione, come pure sulle relazioni di parentela con le altre specie del genere Nothobranchius presenti nello Zambia e nelle regioni adiacenti della Repubblica Democratica del Congo. 89 Introduction The fish fauna of the Luapula/Bangweulu basin in Zambia, which forms the upper part of the large Congo catchment, has been documented in several studies (Ricardo-Bertram, 1943; De Kimpe, 1964; Malaisse, 1976). The killifish found in this basin belong to two families: Poecilidae, with four species previously belonging to the genus Aplocheilichthys (see Wildekamp, 1995) but now placed into the genus Lacustricola (see Huber, 1999) and Nothobrachiidae (see Costa, 2004) with two species (Skelton, 1993). On 26 December 1989, J. Rosenstock collected specimens of an unidentified Nothobranchius species from the Lwingishi River (Fig. 4) S E, 36 km east of Mansa. These differed signiaqua vol. 9 no

A new species of the genus Nothobranchius (Cyprinodontiformes: Nothobranchiidae) from the Luapula River basin, Zambia ficantly in male coloration from the two species, Nothobranchius malaissei

2 A new species of the genus Nothobranchius (Cyprinodontiformes: Nothobranchiidae) from the Luapula River basin, Zambia ficantly in male coloration from the two species, Nothobranchius malaissei Wildekamp, 1978 and N. symoensi Wildekamp, 1978, already known from the Luapula/Bangweulu basin. The Lwingishi River drains into a swamp that is part of the Mansa River system, a tributary to the Luapula. The new fish were temporarily referred to as Nothobranchius species Mansa. Since then this Nothobranchius species has been collected from localities: 20 km east of Mansa S 29 3 E, 15 km west of Samfya S E, from the Luwombwa River S 30 8 E, from the Mulembo River S E and from the Loshi River S E. The undescribed species Nothobranchius was considered to be close to Nothobranchius malaissei (see Wildekamp, 2004). However, after comparing this fish with preserved specimens of N. malaissei and N. symoensi, it was concluded that the species was new to science. It is described here as Nothobranchius rosenstocki. Materials and methods Measurements were taken with the aid of a digital calliper, partly under a dissecting microscope. Counts were taken as described in Amiet (1987). All visible rays of the dorsal and anal fins were counted. The count of scales on the median longitudinal series is the number of scales between the superior junction of the opercular membrane and the base of the caudal fin. Measurements are presented in percentages of standard length (SL). Snout and eye measurements are presented in percentages of head length (HL). Terminology for the cephalic neuromast series follows Scheel (1968) and for the frontal scalation follows Hoedeman (1958). Live specimens of N. rosenstocki (from the Mulembo River, Kasanka National Park) were maintained in the aquarium to determine breeding colours and breeding habits. Abbreviations for the institutions in which the fish were deposited are: MRAC, Musée Royal de l Afrique Centrale, Tervuren; MSNG, Museo di Storia Naturale, Genova. ZAM- are field designations used in publications of authors listed in synonymy. Nothobranchius rosenstocki n. sp. (Figs. 1, 5-7; Table I) Nothobranchius species Mansa, Rosenstock, 1991 Nothobranchius sp. ZAM 92/4, Schmidt, 1999 Fig. 1. Nothobranchius rosenstocki, MSNG 51934, male, paratype, mm SL and female not preserved. Photo by S. Valdesalici. aqua vol. 9 no

3 Stefano Valdesalici and Rudolf H. Wildekamp Table I. Percent of standard length In percent of head length Registration SL (mm) Depth of Depth at Preanal Predorsal Prepelvic Head Interorbital Snout Eye caudal the pelvic length length length length width length diameter peduncle fins MRAC P-0011 (holotype) MRAC P MRAC P-0013 (female) MSNG MSNG TANZANIA 100 Km Fig. 2. Distibution map: open star indicate type locality, solid stars represent other locations. Drawing by S. Valdesalici. 91 aqua vol. 9 no

A new species of the genus Nothobranchius (Cyprinodontiformes: Nothobranchiidae) from the Luapula River basin, Zambia Nothobranchius species Mansa ZAM 97/2, Schmidt, 1999; Wood, 2001 Nothobranchius

4 A new species of the genus Nothobranchius (Cyprinodontiformes: Nothobranchiidae) from the Luapula River basin, Zambia Nothobranchius species Mansa ZAM 97/2, Schmidt, 1999; Wood, 2001 Nothobranchius sp. ZAM 97/3, Schmidt, 1999; Wood 2001 Nothobranchius species aff. malaissei, Wildekamp, 2004 Holotype: MRAC P-0011, male, mm SL; Zambia: Kasanka National Park, Luwombwa River, close to Luwombwa lodge, S 30 8 E. Collected by P. Goudswaart, 8 August 1997, with the help of local women, by means of baskets, in the shallows among shore vegetation. Paratypes: MRAC P-0012, male, mm SL, collecting data as holotype. MRAC P- 0013, female, mm SL, collecting data as holotype. MSNG 51934, male, mm SL preserved aquarium specimen, F3 generation, parents of which were collected in Central Province, Kasanka National Park, Dembo Mukatwe north of Mulembo River, S E, Zambia. Collected by F. Jespersen, September MSNG 51933, male, mm SL, Luapula Province, swamp near Loshi River, 20 km from Mansa (22 Km from the Mansa rest house), on left side of road from Mansa to Samfya, S E, Zambia. Collected by G. Melhuish, April 2002, off-shore, along border vegetation with large hand nets. Comparative material Nothobranchius malaissei : MRAC P ; holotype and 5 paratypes; Zaïre, Shaba Province, Kondale, 1.5 km east of Kabiashia, Luapula drainage, south of Lake Moero. MRAC P ; 6 paratypes, collecting data as holotype, E S. Nothobranchius symoensi: MRAC P ; holotype and paratype; Zaïre, Shaba Province, near Mufumbi, alt m, in the Malinde River valley, a part of the Luapula drainage system, E S. Diagnosis Nothobranchius rosenstocki is distinguished from all other species of the genus by the following combination of unique characters: dorsal fin rays; anal fin rays; male coloration consisting of irregular red reticulation contrasting with light blue background colour on the entire body. Frontal and superior portion of the head red; anal fin with a red distal Fig. 3. The Luwombwa River near the type locality. Photo by D. Rogers. aqua vol. 9 no

Stefano Valdesalici and Rudolf H. Wildekamp Fig. 4. The Lwingishi River. Photo by J. Rosenstock. part. Caudal fin base red spotted, distal part transparent light blue.

Nothobranchius rosenstocki, MSNG 51934, male, paratype, 36.90 mm SL; A) Head, lateral view. B) Head, dorsal view.

Nothobranchius rosenstocki, MRAC 97-089-P- 0011, male, holotype, 34.33 mm SL. Photo by S. Valdesalici. Fig. 7. Nothobranchius rosenstocki, MRAC 97-089-P- 0013, female, paratype, 32.20 mm SL.

5 Stefano Valdesalici and Rudolf H. Wildekamp Fig. 4. The Lwingishi River. Photo by J. Rosenstock. part. Caudal fin base red spotted, distal part transparent light blue. Anterior part of base of dorsal fin with distinct black spots and hardly visible papillae. Sides of female, in contrast to male, not marked but with narrow brown scale margins. Fig. 5. Nothobranchius rosenstocki, MSNG 51934, male, paratype, mm SL; A) Head, lateral view. B) Head, dorsal view. C) Simplified Nothobrachiidae head dorsal view, frontal scale pattern: G-type; anterior neuromasts series: open type (from Scheel, 1968). Drawing by S. Valdesalici. Fig. 6. Nothobranchius rosenstocki, MRAC P- 0011, male, holotype, mm SL. Photo by S. Valdesalici. Fig. 7. Nothobranchius rosenstocki, MRAC P- 0013, female, paratype, mm SL. Photo by S. Valdesalici. 93 Description Morphometric characters are given in Table I. A deep-bodied Nothobranchius with snout rounded and a terminal mouth directed upward. Dorsal fin rays 15-17; anal fin rays Scales on median longitudinal row on caudal fin base. Pattern of cephalic scalation is variable, although most specimens studied show G-type (Fig. 5-B). Anterior neuromast series of open type; central series in two shallow grooves, lined with low lobes. Posterior cephalic neuromast series in curved shallow pits on each side (Fig. 5-B). Preopercular neuromast system in open groove, distal ridge slightly overlapping opercle (Fig.5-A). Collected males reaching up to mm TL. Body laterally compressed and deep. Dorsal profile convex between snout and beginning of dorsal fin; in older males dorsal profile slightly concave on supraoccipital area. All unpaired fins rounded, dorsal and anal fin present small papillate contact organs. Opercular membrane projecting from opercle, distal edge slightly wrinkled. Female smaller than male, maximum size observed 38.9 mm TL. Body less compressed and less deep than of male. Dorsal and caudal fin rounded, anal fin triangular with tip rounded. Anal fin positioned more posteriorly than in the male (Table I). No papillate contact organs on dorsal and anal fin. Opercular membrane not projecting from the opercle. Colour in life: Male (Fig. 1). Body and head scales light blue, most scales with irregular distinct red margin, creating variable reticulated pattern on body and head. Ventral area pale yellowish. Frontal and superior part of head red. Dorsal fin light blue-grey with red spots. Spots near fin base larger and more disaqua vol. 9 no

6 A new species of the genus Nothobranchius (Cyprinodontiformes: Nothobranchiidae) from the Luapula River basin, Zambia tinct than distal ones. Distal spots fusing into narrow lines, parallel to fin rays. Distinct black spots at frontal base of dorsal fin. Anal fin light blue-grey with red spots. Spots smaller towards distal margin, more dense and fused into plain red margin. Basal and central part of caudal fin orange-red with irregular pattern of light blue-grey spots. Spots becoming denser towards margin to form wide light blue-grey margin. Pelvic fin light blue-grey and plain orangered margin. Pectoral fins hyaline with light blue margin. Iris golden with faint dark vertical bar. Female (Fig. 1): Body pale olive-brown, darker grey-brown dorsally, lighter brown to almost silverywhite ventrally. Scales on flanks with narrow brown margin. No dark spot at frontal dorsal fin base. Unpaired and paired fins hyaline. Iris golden, with faint dark vertical bar. Colour in alcohol: Male (Fig. 6). Body scales light brown to whitish, mostly with irregular distinct dark margin, frontal and superior part of head brown. Dorsal and anal fin light brown at the base becoming dark brown on the distal parts. Caudal fin pale light brown. Dark spots hardly visible on the unpaired fins. Pelvic fin light brown. Pectoral fins light brown to whitish. Iris bluish. Female body light brown to whitish (Fig. 7), scales with a narrow brown margin. Unpaired and paired fins pale light brown to whitish. Iris blueish. Distribution Nothobranchius rosenstocki populations have been found scattered over a large area in the Luapula River basin (Fig. 2). Until now, specimens of N. rosenstocki have been found mainly in shallow and vegetated parts of small, slow-flowing rivers which empty into swamps. They were also collected from so-called dembos or water-filled depressions. All habitats with N. rosenstocki were temporary and only filled with water during the wet season and for a short period afterwards. The bottom substrate of these habitats was usually silt or clay with a high humus content. Figs.3 and 4 show the type of habitat in which the fish occur. Presently three groups of localities can be distinguished: Kasanka National Park, the area between Mansa and Samfya, and Kapalala. Further collections are required to determine the full extent of distribution of this species. Etymology Described in honour of John Rosenstock of Hellerup, Denmark, who collected this new species during one of his many journeys in Africa for the Danish Development Assistance Organisation. Laboratory observations Fish kept in aquaria are annual, like all other species of the genus. The eggs of Nothobranchius rosenstocki, spawned in the aquarium, are deposited in the bottom substrate, in this case peat moss. The peat moss containing the fertilized eggs is dried (to the point at which the moss is slightly moist), stored in sealed bags at room temperature (20-25 C) and inspected at regular intervals for the presence of fully-developed embryos. After three to five months of incubation, most eggs contain a fully-developed embryo and if the medium is soaked in fresh water the eggs hatch within a short time. Growth of the fry is rapid. Generally the most mature young may be able to reproduce after 4 to 5 weeks. During incubation, egg development may be interrupted by three diapauses. Development may or may not be arrested (Peters, 1963). Almost all eggs of Nothobranchius rosenstocki that were observed underwent three diapauses. Diapause appears to be an important adaptation for fish living in ephemeral condtions. By going into diapause N. rosenstocki eggs survive the dry season and only hatch when conditions are favourable. Discussion Nothobranchius rosenstocki can be distinguished from all other species of the genus found in the Luapula/Bangweulu basin, N. malaissei and N. symoensi, by meristics, morphometrics, male coloration and general colour pattern. Nothobranchius rosenstocki differs from N. malaissei by the distinctly more anterior position of the dorsal fin (51.8 vs. 58.9% in SL) and the anal fin (58.3 vs. 62.0% in SL). It also differs from it in having a lesser body depth (26.7 vs. 30.6% in SL), smaller head (32.0 vs. 33.4% in SL), smaller eye diameter and narrower interorbital width. Nothobranchius rosenstocki males are characterised by a dorsal/head profile that is convex (slightly concave above the eye in older males) versus the distinctly concave dorsal/head profile of N. malaissei. The male N. rosenstocki differs from male N. malaissei by its orange-red coloration of the lower head and throat, versus a light blue coloration with worm-like red markings. It also differs by the spot pattern of the dorsal fin (faint bluish spots on the distal part versus large well-defined red spots over the entire fin), caudal fin pattern (blue-grey spots on a orange-red background and light blue-grey margin versus distinct spots that partly form cross-bars) (see also illustration in Malaisse, 1997), and the shape of the posterior end of the anal fin (rounded vs. slightly pointed). Nothobranchius rosenstocki differs in meristics from N. symoensi in having fewer dorsal fin rays (15-17 vs ) and anal fin rays (16-17 vs ). It differs by its lesser body depth (26.7 vs. 30.4% in SL) and smaller eye diameter. The colour pattern of male N. rosenstocki differs from that of N. symoensi in lackingl a distinct light blue margin in the unpaired fins. aqua vol. 9 no

7 Stefano Valdesalici and Rudolf H. Wildekamp Nothobranchius rosenstocki males have a faint bluegrey margin in the dorsal and caudal fin only, while the anal fin has a distinct red margin and the pattern of the caudal fin that is banded in N. symoensi and spotted in N. rosenstocki. Males of N. symoensi also lack the distinct black spots that are present on the lower frontal part of the dorsal fin. The Nothobranchius species of Zambia and the adjacent parts of the Democratic Republic of Congo and Namibia are here organised into three groups based on male colour patterns: 1. The Nothobranchius brieni group including N. brieni Poll, 1938 and N. hassoni Valedsalici & Wildekamp, 2004 from the Lufira/Lualaba River system. Males of both species are characterised by a wide light band in the anal fin above a dark brown to black margin and dark red spotted proximal part of the caudal fin. In N. brieni the caudal fin also has a light vertical band reduced to a light triangle in the lower corner of the caudal fin. 2. The Nothobranchius malaissei group formed by N. malaissei, N. symoensi and N. rosenstocki, all restricted to the Luapula River system. Males of these taxa are characterised by an irregular reticulated pattern on the sides that may form irregular cross bars. The red pattern of the caudal fin is spotted and a light margin may be present. 3.The Nothobranchius polli group formed by N. polli Wildekamp, 1978, N. kafuensis Wildekamp & Rosenstock, 1989 and N. species from Caprivi Strip of Namibia (see Wildekamp, 2004), all living in the upper Lufira, middle Zambezi or Kafue river systems. These species can be distinguished by the wide, light submarginal band on the caudal fin in front of a dark brown to black margin, a wide light band on the anal fin, heavily spotted with red in its proximal half. Male colour patterns of all three groups suggest a more distant relationship with the species of the Nothobranchius taeniopygus group that occurs in western and central Tanzania, from which they were probably separated by the formation of the (western) Great Rift Valley with a prior to Pliocene common ancestor (Beadle, 1974). Acknowledgements The authors wish to thank P. Goudswaart, G. Melhuish and F. Jespersen for collecting and donating fish as well as providing information on their origin, Kim Farmer and Edmund Farmer (both of Kasanka National Park) and David Rogers for photographing the type locality. The authors thank Francesca Fontana, Annalisa Varriale, Laura Pedrazzini and Carlotta Montanari for their assistance with the first draft of the manuscript. We also like to express our gratitude to the authorities of MRAC, vertebrate section, and Giuliano Doria (MSNG) for access to the collections under their care. References Amiet, J Faune du Cameroun. Fauna of Cameroon. Vol. 2. Le genre Aphyosemion Myers (Pisces: Teleostei: Cyprinodontiformes). Sciences Naturales, Compiègne, 262 pp. Beadle, L. C The inland waters of tropical Africa. An introduction to tropical limnology. Longman, London, 365 pp. Costa, W. J. E. M 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 (2): De Kimpe, P Contribution à l étude hydrobiologique du Luapula-Moëro. Annales du Musée Royal de l Afrique Centrale, Série 8, (Zoologique) 128, 238 pp. Hoedeman, J The frontal scalation pattern in some groups of tooth carps (Pisces: Cyprinodontiformes). Bulletin of Aquatic Biology, 1: Huber, J. H Updates to the phylogeny and systematics of the African Lampeye schooling Cyprinodonts (Cyprinodontiformes: Aplocheilichthyinae). Cybium, 23 (1): Malaisse, F Ecologie de la rivière Luanza. In: Symoens, J. J. (ed.). Exploration hydrobiologique du Lac Bangweolo et de Luapula, 17 (2), 151 pp. Malaisse, F Se nourrir en forêt claire africaine. Gembloux, Belgium, 384 p. Peters, N Embryonale Anpassungen oviparer Zahnkarpfen aus periodisch austrocknenden Gewässer. Internationaler Revue der Gesammten. Hydrobiologie, 48 (2): Ricardo-Bertram, C. K The fishes of the Bangweulu region. Journal of the Limnological Society, 41 (278): Rosenstock, J Zambia Journal of the American Killifish Association, 24 (4-6): Skelton, P. H A complete guide to the freshwater fishes of southern Africa. Southern Book Publishers, Halfway House, South Africa, 388 pp. Scheel, J. J Rivulins of the Old Word. Tropical Fish Hobbyist Publication, Neptune City, USA, 480 pp. Schmidt, O Auf Killi-Jagd nach Sambia. Deutsche Killifisch Gemeinschaft Journal, 31 (4): Valdesalici, S. & R. H. Wildekamp A new species of the genus Nothobranchius Peters 1868 from the Lufwa River basin, Katanga province, Democratic Republic of Congo (Pisces, Cyprinodontiformes, Aplocheilidae). Estratto dagli Annali del Museo Civico di Storia Naturale G. Doria. Genova, 96: Wildekamp, R. H Redescription of Nothobranchius brieni Poll, 1938 and the description of three new Nothobranchius species (Pisces, 95 aqua vol. 9 no

8 A new species of the genus Nothobranchius (Cyprinodontiformes: Nothobranchiidae) from the Luapula River basin, Zambia Cyprinodontidae) from the provinces of Shaba, Zaïre. Revue de Zoologie Africaine, 92 (2): Wildekamp, R. H A world of killies. Atlas of the oviparous cyprinodontiform fishes of the world. Volume 2. Mishawaka, Indiana, 384 pp. Wildekamp, R. H A world of killies. Atlas of the oviparous cyprinodontiform fishes of the world. Volume 4. Mishawaka, Indiana, 398 pp. Wood, T A search for Notho s in Zambia Killi-News British Killifish Association Journal, 433: aqua vol. 9 no

Nothobranchius seegersi (Cyprinodontiformes: Nothobranchiidae),

& pp. Bonn zoological Bulletin Volume 60 Issue 1 89-93 Bonn, May 2011 Nothobranchius seegersi (Cyprinodontiformes: Nothobranchiidae), a new annual killifish from the Malagarasi River drainage, Tanzania