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A new dwarf alestid from the vicinity of Inga on the lower Congo River, Bas Congo Province, Democratic Republic of Congo is described. Assignment of the new taxon to the poorly defined genus, Micralestes, is discussed and justified on the basis of available morphological character data. With the recognition of Micralestes schelly sp. nov., a total of six Micralestes are now known to inhabit the 350 km stretch of the Congo River from Pool Malebo to Boma near the river’s estuary. These are Micralestes acutidens (Peters, 1852), Micralestes humilis Boulenger, 1899, Micralestes lualabae Poll, 1967, Micralestes holargyreus (Günther, 1873), Micralestes stormsi Boulenger, 1902, and the new species Micralestes schelly. Of these Micralestes schelly and Micralestes holargyreus are considered herein as restricted-range endemics of the lower Congo River. An illustrated key to Micralestes of the lower Congo River is provided.

The current study explores information on fish diversity and fishing gears used in Tomas Dam Danbatta, Kano State and Daberam Dam Daura, Katsina State. From the results 5 different species belonging to 3 families were found in Tomas dam, and these are; Tilapia zilli, Oreochromis niloticus and Sarotherodon galilaeus belonging to the Family Cichlidae, Clarias gariepinus from the Family Claridae and Lates niloticus from the Family Centropomidae. Whereas in Daberam Dam, 6 species belonging to 5 families were observed and these are: Oreochromis niloticus, Hemichromis bimaculatus (Family Cichlidae), Clarias gariepinus (Family Claridae) and Eutropius niloticus, Hyperopiss bebe and Alestes beramoze from the Family Shilbeidae, Mormyridae and Alestidae respectively. The research also revealed that, Cichlidae were the most dominant fish type in these two Dams with Oreochromis niloticus leading specie in Tomas dam, with 61% percentage abundance, while Hemichromis bimaculatus is the most abundant species in Daberam Dam having 85% percentage abundance. The types of fishing gears used in both Tomas and Daberam Dam are similar with triggered trap dominating the fishing site in each dam. Keywords: Cast net, Daberam Dam, Hooks, Line net, Tomas Dam, Triggered trap.

The overall most parsimonious hypothesis of relationships based on 200 characters indicates that the Alestidae is the closest relative of Chalceus, a genus previously assigned to the Neotropical Characidae. Chalceus is shifted into the Alestidae, which becomes the only trans-Atlantic family level group within the Characiformes. Various previously proposed suprageneric assemblages within the Alestidae (e.g. Petersiini) failed to delimit monophyletic groups under the intrafamilial phylogenetic analysis. The evaluation of fossil alestids within the context of the phylogeny indicates that the ancestors of Alestes, Arnoldichthys, Brycinus, Bryconaethiops and Hydrocynus evolved prior to the early Eocene (Cuisian of Upper Ypresian), 49–54.8 million years ago, with the fossil Alestoides most closely related to Alestes. The phylogenetic information further indicates a minimum age of 90–112 million years for the Alestidae. Contrary to previous hypotheses, the fossil African Sindacharax was found to be most similar to the clade including the alestid genus Bryconaethiops rather than most closely related to the South American subfamily Serrasalminae. Evaluation of the fossil Mahengecharax carrolli fails to support its hypothesized placement as the sister group to all Recent members of the Alestidae. Two separate episodes of miniaturization and one episode of gigantism occurred within the evolution of the Alestidae. © 2005 The Linnean Society of London, Zoological Journal of the Linnean Society, 2005, 145, 1−144. No claim to original US government works.

A single specimen of the anterior portion of a small fish was collected from the Eocene Mahenge site of Tanzania in 1996. The specimen, preserved as part and counterpart natural mold, is identified as belonging to a characiform fish, although the presence of a Weberian apparatus has not been confirmed beyond doubt. Features of the bones, such as the prominent lateral ridge on the anterodorsal corner of the opercle, the fused postcleithra 2+3, and the lack of a dentary symphyseal hinge, indicate that the fish is related to the Citharinidae and Distichodontidae. The fossil cannot be included in any known genus, and is described here as a new genus and species, Eocitharinus macrognathus. The fossil record of characiforms includes few articulated skeletons, of which only one had been reported previously from Africa, described in the family Characidae (=Alestidae).

Four specimens of a small fossil fish were collected from the Eocene Mahenge site of Tanzania. The specimens, preserved as part and counterpart natural moulds, are identified, predominantly based on the structure of the caudal skeleton, as members of the Characiformes, probably the sister group to the living African Alestidae. The area just behind the skull, in the two specimens that include this area, is distorted, and therefore it is difficult to identify the bones of the Weberian apparatus, although that structure does appear to be present. The fossil record of characiforms includes few articulated skeletons, with only one other African species previously reported from much younger deposits. The new specimens from Mahenge are described here as a new genus and species, Mahengecharax carrolli.

The family Alestidae (also referred to as the African Characidae) comprises the African dwarf forms ("Petersiini") and the genera Alestes, Brycinus, Bryconaethiops, and Hydrocynus. Although several authors have presented characters to support the monophyly of the family, a cladistic analysis of the group has not been published. Furthermore, the interrelationships of the constituent groups are the subject of some controversy. A cladistic analysis of the Alestidae is presented, including characters to support the monophyly of the family. The results of this study indicate that several species should be removed from the genus Brycinus, that Hydrocynus is the sister group of Alestes s.str. (containing only five species), and that the dwarf alestids ("Petersiini") do not form a monophyletic group.

Laan, Richard Van Der, Eschmeyer, William N., Fricke, Ronald (2014): Family-group names of Recent fishes. Zootaxa 3882 (2): 1-230, DOI: http://dx.doi.org/10.11646/zootaxa.3882.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3882.1.1

Made available in DSpace on 2015-02-02T12:39:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-04-01Bitstream added on 2015-02-02T13:08:27Z : No. of bitstreams: 1 S1679-62252014000200419.pdf: 6936041 bytes, checksum: ff695abb2ca2a3eba28c5f0d9df7fe7b (MD5) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) A espermiogênese e os espermatozoides de seis gêneros que compõem a família Alestidae mais o gênero Chalceus são descritos. A espermiogênese é muito similar em todas as espécies de Alestidae analisadas e pode ser considerada como sendo o Tipo I e suas variações. Neste tipo de espermiogênese, o flagelo das espermátides iniciais dispõe-se lateral ao núcleo. A rotação do núcleo em direção ao complexo centriolar está presente. A rotação nuclear é completa, atingindo 90 graus, em Bryconalestes longipinnis, Brachypetersius altus, Brycinus imberi, B. lateralis e Alestopetersius compressus; incompleta, atingindo 20 graus, em Micralestes acutidens e Rhabdalestes rhodesiensis. A morfologia dos espermatozoides de Alestidae varia desde o núcleo medial com cromatina fibrilar no gênero Brycinus, considerado mais basal, até o núcleo muito excêntrico com cromatina altamente compactada, nos gêneros Rhabdalestes e Micralestes, considerados mais derivados dentro de Alestidae. Chalceus possui um espermatozoide muito similar a Brycinus, compartilhando entre eles o aspecto fibrilar da cromatina no núcleo. Esta característica até o momento só foi observada nestes dois gêneros dentre os Characiformes Africanos e Neotropicais. Spermiogenesis and spermatozoa in six genera of the African family Alestidae plus the Neotropical genus Chalceus are described. Spermiogenesis is quite similar in all Alestidae and is identified as Type I and its variants. In Type I spermiogenesis, the flagellum of earliest spermatids lies lateral to the nucleus, and rotation of the nucleus towards the centriolar complex is observed. Nuclear rotation is complete reaching 90 degrees in Bryconalestes longipinnis, Brachypetersius altus, Brycinus imberi, B. lateralis, and Alestopetersius compressus; and is incomplete reaching 20 degrees in Micralestes acutidens and Rhabdalestes rhodesiensis. Spermatozoa morphology varies from a medial nucleus with fibrillar chromatin in the most basal genus Brycinus to a strongly eccentric nucleus with highly condensed chromatin in the more derived Rhabdalestes and Micralestes. Chalceus has a very similar spermatozoon to that found in Brycinus sharing the fibrillar aspect of the chromatin in the nucleus. This feature is so far only observed in these two genera among African and Neotropical characiform fishes. Universidade Estadual de Campinas Programa de Pós-Graduação em Biologia Celular e Estrutural Universidade de São Paulo Instituto de Biociências Departamento de Genética e Biologia Evolutiva Universidade Estadual Paulista Júlio de Mesquita Filho Instituto de Biociências Departamento de Morfologia Universidade Estadual Paulista Júlio de Mesquita Filho Instituto de Biociências Departamento de Morfologia

Two new species of Annulotrema Paperna & Thurston, 1969 were collected from the gills of the African tiger fish, Hydrocynus brevis, from the Gambia River basin in the Niokolo-Koba National Park, Senegal. Annulotrema besalis n. sp. is characterized by having a male copulatory organ (MCO) composed of an arcuate copulatory tube articulated to an eight-shaped accessory piece with terminal claw. The new species resembles Annulotrema pikei (Price, Peebles & Bamford, 1969) in having morphologically similar types of haptoral sclerites and MCO. As a result of the differential diagnosis made for A. besalis n. sp., new information on taxonomically important features of A. pikei is provided based on illustrations of the sclerotized parts of the holotype from Hydrocynus vittatus. The report of A. pikei on the gills of Hydrocynus forskahlii by Paperna in 1979 is shown to be erroneous. Annulotrema uncata n. sp. is similar to Annulotrema alestesimberi Paperna, 1973 in its possession of a coiled copulatory tube with about two and a half rings. Features distinguishing the new species include the sharply curved shaft of the ventral anchor, the base of the copulatory tube extending to a sock-like structure and a leech-shaped vagina. The necessity of emending the generic diagnosis of Annulotrema is briefly discussed.

Fishes of the order Characiformes are a diverse and economically important teleost clade whose extant members are found exclusively in African and Neotropical freshwaters. Although their transatlantic distribution has been primarily attributed to the Early Cretaceous fragmentation of western Gondwana, vicariance has not been tested with temporal information beyond that contained in their fragmentary fossil record and a recent time-scaled phylogeny focused on the African family Alestidae. Because members of the suborder Citharinoidei constitute the sister lineage to the entire remaining Afro-Neotropical characiform radiation, we inferred a time-calibrated molecular phylogeny of citharinoids using a popular Bayesian approach to molecular dating in order to assess the adequacy of current vicariance hypotheses and shed light on the early biogeographic history of characiform fishes. Given that the only comprehensive phylogenetic treatment of the Citharinoidei has been a morphology-based analysis published over three decades ago, the present study also provided an opportunity to further investigate citharinoid relationships and update the evolutionary framework that has laid the foundations for the current classification of the group. The inferred chronogram is robust to changes in calibration priors and suggests that the origins of citharinoids date back to the Turonian (ca 90 Ma) of the Late Cretaceous. Most modern citharinoid genera, however, appear to have originated and diversified much more recently, mainly during the Miocene. By reconciling molecular-clock- with fossil-based estimates for the origins of the Characiformes, our results provide further support for the hypothesis that attributes the disjunct distribution of the order to the opening of the South Atlantic Ocean. The striking overlap in tempo of diversification and biogeographic patterns between citharinoids and the African-endemic family Alestidae suggests that their evolutionary histories could have been strongly and similarly influenced by Miocene geotectonic events that modified the landscape and produced the drainage pattern of Central Africa seen today.

Alestidae is a clade of African characiform fishes including 19 extant genera and approximately 105 species that are known from Afro-Arabia, with records reported from the Eocene-Oligocene Jebel Qatrani Formation of Egypt, the Eocene Mahenge crater lake of Tanzania, and early Oligocene to Miocene sites on the Arabian Plate. Here we report the first record of alestid fishes from the late Oligocene Nsungwe Formation in the Rukwa Rift Basin of southwestern Tanzania. The Nsungwe alestid sample is composed of 92 teeth spanning a range of sizes and morphologies. Teeth are examined with regard to cusp number and organization, tooth position and replacement, and in the context of alestid jaw organization using modern, comparative representatives. Results suggest that at least two alestid taxa are represented in Nsungwe Formation localities. Hydrocynus teeth exhibit a single, conical cusp. Several of these specimens preserve a mesiodistally expanded crown and concave surface on the lingual aspect of the t...

Two new species of Bathyaethiops (Teleostei: Characiformes: Alestidae) are described. Bathyaethiops baka n. sp. is a dwarf species with the largest known specimen being only 24.4 mm SL. The species is characterized by an incomplete squamation and a large humeral spot. Bathyaethiops baka n. sp. is known so far only from the Ngoko River of Southeastern Cameroon, a tributary of the Sangha River in the northern Congo basin. The second species, Bathyaethiops flammeus n. sp., shows a diagnostic spot in front of the dorsal-fin base, which is devoid of melanophores and bright red in life. The species is described from the Bakere River at Yambula-Bakere, a locality north-west of Kisangani in the Central Congo basin. Other records of Bathyaethiops flammeus n. sp. from the Tshuapa respectively Ruki River at Boende and Eala, Central Congo basin, suggests a wider geographic distribution. A key to all species of Bathyaethiops is provided.

Alestopetersius conspectus, new species Fig. 4 Holotype. AMNH 253473, 3, 52.9 mm SL, Democratic Republic of Congo, Bandundu Province, Kwilu River at Carrefour, 05.19160�� S, 18.94947 �� E, Coll. J.J. Mbimbi Mayi Munene, 24 February 2011. Paratypes. AMNH 253475, 9 specimens, 42.3���53.6 mm SL, 2 CS, same data as holotype.��� AMNH 253476, 10 specimens, 45.5���56.9 mm SL, 2 CS, Democratic Republic of Congo, Bandundu Province, Kwilu River at Kwilu beach, 05.04810��S, 18.83968 ��E, Coll. J.J. Mbimbi Mayi Munene, 19 February 2011.��� AMNH 253477, 5 specimens, 42.4���49.2 mm SL, Democratic Republic of Congo, Bandundu Province, Democratic Republic of Congo, Bandundu Province, Kwilu River at Mbuji, 05.07180��S, 18.86935 ��E, Coll. J.J. Mbimbi Mayi Munene, 22 February 2011.��� MRAC B 1-19 -P- 5 -6, 2 specimens, 44.8���44.9 mm SL, same data as holotype.��� ZSM 40759, 2 specimens, 45.4 ���53.0 mm SL, same data as AMNH 253476.���CU 96797, 2 specimens, 42.3���44.3 mm SL, same data as AMNH 253477. Diagnosis. Alestopetersius conspectus, new species, is distinguished from A. smykalai, A. leopoldianus, A. nigropterus, A. caudalis, and A. sp. ���mbuji��� in the possession of 12 (vs. 10) circumpeduncular scales. It is readily distinguished from A. brichardi, A. compressus, A. hilgendorfi, and A. tumbensis in the possession of a caudal-fin pigmentation consisting of a median black band extending to the caudal-fin margin and flanked by dense black bands in both upper and lower fin lobes. Alestopetersius bifasciatus, which shares similar caudal fin pigmentation, is distinguished from A. conspectus by the absence of a broad mid-lateral band on the body, and in tooth morphology. Description. Medium-sized species, maximum size 56.9 mm SL. See Figure 4 for general appearance and Table 1 for summary of morphometric and meristic data. Relatively gracile and shallow-bodied, body depth 26.4��� 34.5 % SL (mean 32.1), greatest depth at vertical through pelvic-fin insertion. Head length 20.4���29.7 (mean 27.5), eye large, bony orbit diameter 28.2���37.2 % HL (mean 34.9). Dorsal head profile straight from upper lip to nape, gently convex from that point to dorsal-fin origin. Dorsal body profile gently convex along dorsal-fin base to caudal-fin base, ventral body profile gently convex between isthmus and anal-fin base, caudal peduncle slightly longer than deep. Mouth terminal, lower jaw prominent and slightly prognathous. Premaxilla with two teeth in outer row, each bearing five cusps, positioned opposite interspaces between and alternating with, four inner row teeth, each bearing 6���8 cusps (Fig. 5). Outermost premaxillary tooth is markedly compressed and elongate with 7 or 8 small evenly sized cusps and a low median cusp. Dentary with four teeth in outer row, each bearing 6 or 7 cusps, outermost tooth smallest in jaw. No inner row teeth on dentary. Dorsal-fin rays, ii 8 anal-fin rays iii, 18-20 (mode 19). Origin of dorsal fin slightly in advance of vertical through pelvic-fin insertion. There is muted sexual dimorphism in fin shape; anal-fin margin convex in mature males, and concave in females and juveniles. The first 4 or 5 branched rays of dorsal fin of mature males somewhat elongated and filamentous. Body covered with small, regularly imbricate scales. Lateral line complete, with 31���34 pored scales to caudal flexion, 6.5���7 scale rows between lateral line and dorsal-fin insertion, 2.5 between lateral line and pelvic-fin insertion, 12 circumpeduncular scales. Twelve to 14 elongate gill rakers arrayed along lower limb of first arch. Total vertebral count 36 or 37 (mode 37). Miscellaneous osteological features. Seven supraneurals are situated above the first seven rib-bearing vertebrae anterior to first dorsal-fin pterygiophore (Fig. 6 A). This condition contrasts with that in most other species examined which possess only 6 supraneurals interdigitating with neural spines of six predorsal vertebrae (Fig. 6 B). We note that Alestoptersius leopoldianus also exhibits 7 rib-bearing vertebrae anterior to dorsal fin pterygiophore, but unlike A. conspectus has 6 rather than 7 supraneurals. Both Alestopetersius tumbensis and Alestopetersius bifasciatus share the modal Alestopetersius configuration with 6 supraneurals interdigitating with 6 vertebrae anterior to the dorsal fin pterygiophore. The condition in the single individual of A. sp. ���mbuji��� is not discernable in radiographs. Coloration. In alcohol (Fig. 4 A&C), base body coloration pale creamy brown with darker basal crescents at contact zones of contiguous scales on dorsum. In males faint humeral stripe present above pectoral fin, but no trace of humeral stripe present in preserved females (Fig. 4 C). In males (Fig. 4 A) a broad black band extends from behind opercle, thickening gradually to caudal peduncle base, then narrows and extends to posterior caudal-fin margin. Distinctive broad black band in each caudal-fin lobe flank central black band and are separated from it by white bands. Remaining fins dusky hyaline, leading edge of pectoral fin dark brown or black. In females coloration similar but mid-lateral band and caudal-fin bands somewhat muted (Fig. 4 C). In life (Fig. 4 B&D) all individuals are iridescent silver with greenish-copper reflections anterolaterally, becoming bluish on flanks and caudal peduncle. Mid-lateral band is obscured anteriorly on body but clearly marked on caudal peduncle. Markings on caudal fin as in preserved specimens but much of the white interspaces between black bands are bright orange. Distribution. Currently known from the Kwilu River in the vicinity of Kikwit (Fig. 1). Collections in the main channel of the Middle Congo River, the Kasai main channel in the region of Bandundu, and Lulua River (a neighboring tributary Kasai) did not recover any individuals of A. conspectus despite intensive sampling, suggesting that the species may be a Kwilu endemic. Ecology and habitat. Numerous specimens of Alestopetersius conspectus were collected at all sample sites along a 35 km stretch of the river (Fig. 1). Most were collected using seine nets at depths of between 1��� 2 m. Water temperature in the shallows where most specimens were collected was between 21���22.5 o C and pH ranged from 5.8���6.5. The Kwilu River at the sampling sites is between 15���40 meters wide and the banks are variously covered with dense, undisturbed riparian vegetation, heavily degraded urban areas, and cleared agricultural areas (Mbimbi & Stiassny 2011). Female specimens contain numerous, maturing eggs in the ovaries and males have enlarged testes suggesting that reproductive activity was approaching at time of capture (February). Short guts (ca. 60 % of SL when unraveled) and large stomachs with 6���8 fleshy pyloric caeca are suggestive of a carnivorous diet, and all specimens examined contained large numbers of insect head capsules and disarticulated body parts, most of terrestrial origin, with a preponderance of ants and small midges presumably taken at the water surface. Etymology. Conspectus, from the Latin, in reference to the conspicuous markings on the caudal fin and striking, bright coloration of the species in life., Published as part of Munene, Jos�� Justin Mbimbi Mayi & Stiassny, Melanie L. J., 2012, A new Alestopetersius (Characiformes: Alestidae) from the Kwilu River (Kasai basin) of central Africa; with a phylogeny for the genus and synonymy of Duboisialestes, pp. 59-68 in Zootaxa 3166 on pages 64-67, DOI: 10.5281/zenodo.213011, {"references":["Mbimbi, J. J. & Stiassny, M. L. J. (2011). Fishes of the Kwilu River (Kasai basin, central Africa); a list of species collected in the vicinity of Kikwit, Bandundu Province, Democratic Republic of Congo. Check List, 7 (5), 691 - 699."]}

A new Alestopetersius is described from the Kwilu River in the Kasai basin of the Democratic Republic of Congo. Alesto- petersius conspectus, new species, is readily distinguished from all congeners based on attributes of squamation and col-oration. It is distinguished from “Duboisialestes” tumbensis by tooth morphology and in the possession of a distinctivecaudal-fin pigmentation patterning consisting of a median black band extending to the caudal-fin margin and flanked bydense black bands in both upper and lower fin lobes. “Duboisialestes” bifasciatus, which shares similar caudal-fin pig-mentation patterning, is distinguished from A. conspectus by the absence of a broad mid-lateral band on the body, and bytooth morphology. Results from an analysis of the relationships and generic composition of the Alestidae provide supportfor the monophyly for Alestopetersius inclusive of the members of the genus Duboisialestes, which are placed into syn-onomy with the former.Une nouvelle espece de Alestopetersius est decrite de la riviere Kwilu dans le bassin du Kasai de la RepubliqueDemocratique du Congo. Alestopetersius conspectus, nouvelle espece, se distingue tres facilement de tout ses congeneressur les attributs de la squamation et coloration. Cette espece est distinguee de “Duboisialestes” tumbensis par la morphol-ogie des dents et par la possession d'un type de pigmentation de la nageoire caudale composee d’une bande noire medianes'etendant de la marge de la caudale et flanquee de denses bandes noires dans les deux lobes superieur et inferieur de lanageoire. “Duboisialestes” bifasciatus qui partage le meme type de pigmentation de la nageoire caudale, se distingue de A. conspectus par l'absence d'une large bande mi-laterale sur le corps, et par la morphologie des dents. Les resultats d'uneanalyse des relations et de la composition generique du Alestidae fournissent un soutien pour la monophylie des Alestopetersius incluant les membres du genre Duboisialestes, qui sont places en synonymie avec le genre precedent.

The Characiformes are distributed throughout large portions of the freshwaters of Africa and America. About 90% of the almost 2000 characiform species inhabit the American rivers, with their greatest diversity occurring in the Neotropical region. As in most other groups of fishes, the current knowledge about characiform myology is extremely poor. This study presents the results of a survey of the mandibular, hyopalatine, and opercular musculature of 65 species representing all the 18 traditionally recognized characiform families, including the 14 subfamilies and several genera incertae sedis of the Characidae, the most speciose family of the order. The morphological variation of these muscles across the order is documented in detail and the homologies of the characiform adductor mandibulae divisions are clarified. Accordingly, the mistaken nomenclature previously applied to these divisions in some characiform taxa is herein corrected. Contradicting some previous studies, we found that none of the examined characiforms lacks an A3 section of the adductor mandibulae, but instead some taxa have an A3 continuous with A2. Derived myological features are identified as new putative synapomorphies for: the Characoidei; the clade composed of the Alestidae, Characidae, Gasteropelecidae, Cynodontoidea, and Erythrinoidea; the clade Cynodontoidea plus Erythrinoidea; the clade formed by Ctenoluciidae and Erythrinidae; the Serrasalminae; and the Triportheinae. Additionally, new myological data seems to indicate that the Agoniatinae might be more closely related to cynodontoids and erythrinoids than to other characids.

Background. Despite the importance of Lake Tanganyika's biodiversity for science and the livelihoods of the riparian people, high-resolution surveys of the fish biodiversity are sparse and fragmentary, especially along the western (Congolese) shoreline. The coast suffers locally from intensive human activities and lacks adequate protective measures or nature reserves. However, in view of the intra-lacustrine endemism of this fish fauna, conservation needs to be managed lake-wide at a fine scale, necessitating detailed inventories on fish species distribution. The study aims at updating knowledge on fish diversity and distribution along the north-western and central western shores of Lake Tanganyika. Materials and methods. Fish specimens were collected using gill-and seine nets, by snorkelling and SCUBA diving, and through purchases on the local markets. Results. Over 28 locations were sampled, and 84 cichlid- and 30 non-cichlid fish species (belonging to Protopteridae, Clupeidae, Cyprinidae, Alestidae, Claroteidae, Clariidae, Malapteruridae, Mochokidae, Poeciliidae, Latidae, and Mastacembelidae) collected. Conclusion. Our records substantially expand the known range of fish species in a range of habitats. As numerous specimens are hard to assign to nominal species, a taxonomic revision of a number of genera is underway. It should take into account intraspecific geographic variation.

Phylogenetic relationships within the family Alestidae were investigated using parsimony, maximum likelihood, and Bayesian approaches based on a molecular dataset that included both nuclear and mitochondrial markers. Multiple representatives of all but two of the recognized alestid genera were included, which allowed for testing previous hypotheses of intergeneric relationships and the monophyly of several genera. The phylogenetic position of the Neotropical genus Chalceus with respect to the family Alestidae was also examined. In order to understand the temporal context of alestid diversification, Bayesian methods of divergence time estimation using fossil data in the form of calibration priors were used to date the nodes of the phylogenetic tree. Our results rejected the monophyly of the family as currently recognized (Alestidae sensu lato) and revealed several instances of poly- and paraphyly among genera. The genus Chalceus was recovered well nested within Neotropical characiforms, thus rejecting the hypothesis that this taxon is the most basal alestid. The estimated mean divergence time for the alestid clade (Alestidae sensu stricto) was 54 Mya with a 95% credibility interval of 63-49 Mya. These results are incongruent with the hypothesis that the origin of the family Alestidae predates the African-South American Drift-Vicariance event.

Bryconaethiops yseuxi Boulenger, 1899, originally described from “Haut Congo”, is rehabilitated. The species was synonymized, successively with B. microstoma (Gunther, 1873) and B. macrops Boulenger, 1920, subsequently rehabilitated, and then again considered as a junior synonym of B. microstoma. Bryconaethiops yseuxi is here considered as a valid species, easily distinguished from all other Bryconaethiops species by its small size (maximum: 72.2 mm SL), 7.5 rows of scales between the dorsal‐fin origin and the lateral line; 11–13/1/8–12 gill rakers on the first gill arch and long dorsal‐fin and anal‐fin bases, respectively, 15.7–17.6% of SL and 22.7–25.9% of SL.

This is the first extensive study of a freshwater fish fauna from the Pliocene site of Koro-Toro (Chad), aged 3.58 ± 0.27 Ma. The assemblage includes an abafish (Mormyriformes, Gymnarchidae: Gymnarchus ), a tigerfish (Characiformes, Alestidae: Hydrocynus ), six different catfishes (Siluriformes, Ariidae: Carlarius ; Bagridae: Bagrus ; Claroteidae: Clarotes and Auchenoglanis ; Mochokidae: Synodontis ; Clariidae: Clarias or Heterobranchus ), perciform fishes (Perciformes, Latidae: Lates sp. cf. niloticus , and Cichlidae indet.), and a pufferfish (Tetraodontidormes, Tetraodontidae: Tetraodon ). The diversity is relatively low when compared with other Chadian Neogene sites. This is probably mostly explained by the wind erosion of the outcrops being responsible for the lack of minute remains. However, we recognize that the aquatic environment recorded corresponds to open waters.

This is the first extensive study of a freshwater fish fauna from a Pliocene site in Central Africa, based on fossils collected at the KL2 site in the fossiliferous area of Kolle (Lower Pliocene, Chad). A relatively high fish diversity is revealed, confirming the presence of 19 taxa: Polypteriformes, Polypteridae (Polypterus sp.); Osteoglossiformes, Osteoglossidae (Heterotis sp.), Mormyriformes, Gymnarchidae (Gymnarchus sp. cf. niloticus); Cypriniformes, Cyprinidae (Labeo sp.); Characiformes, Alestidae (Hydrocynus; Alestinae type Alestes/Brycinus; Sindacharax sp. cf. deserti, Sindacharax sp.), Distichodontidae (Distichodus sp.); Siluriformes, Ariidae (cf. Calarius), ?Bagridae (cf. Bagrus), Claroteidae (cf. Clarotes), Mochokidae (Synodontis sp.), Clariidae (Clarias sp. or Heterobranchus sp.); Perciformes family indet. (Semlikiichthys sp. cf. darsao), Latidae (Lates sp. cf. niloticus), Cichlidae indet., and Perciformes indet.; Tetraodontiformes Tetraodontidae (Tetraodon sp.). The aquatic environment corresponding to the fossil fish assemblage might be a floodplain crossed by well-oxygenated open waters. Compared with a contemporaneous East African region, the mid-Pliocene Chadian fish diversity reveals a certain endemicity, while connections between the Niger and the Chadian basin are suspected because of the presence of a freshwater ariid fish in Kolle.

Micralestes acutidens - BMNH 1861.3.10: 3-4, syntype, 1; AMNH 227634, 1; AMNH 239475, 5, 2 C&S, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

Virilia pabrensis - AMNH 50858, 6, 1 C&S., Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

Hemmigrammopetersius barnardi - AMNH 19861, 10, 3 C&S, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

[[Genus Micralestes]] Roberts & Stewart (1976) in their work on the fishes of the lower Congo River reported the presence of two Micralestes in their collections: M. acutidens (Fig. 1A) and M. humilis (Fig. 1C). Recent collections in the region also include specimens of M. lualabae (Fig. 1D), M. stormsi (Fig. 1E) and M. holargyreus (Fig. 1B). In addition to these, a collection made in the vicinity of Inga revealed the presence of a population of diminutive alestid that appears most closely to resemble Micralestes but that are not assignable to any described Micralestes or to any other species dwarf African alestid.

Rhabdalestes sp.- AMNH 227602, 18, 1 C&S

M. ambiguous - MRAC G.966 a -c, paratypes, 2, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

Duboisialestes tumbensis - AMNH 238391, 5, 3 C&S, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

B. huloti - AMNH 238374, 2, 1 C&S, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

Rhabdalestes aeratus - AMNH 235768, paratypes, 10, 1 C&S, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

Alestopetersius brichardi - AMNH 240416, 5, 2 C&S, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

Brycinus macrolepidotus - AMNH 240383, 6, 1 C&S, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

R. maunensis - AMNH 217434, 5, 1 C&S, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

Bathyaethiops caudomaculatus - AMNH 238423, 5, 2 C&S, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

Brachypetersius altus - AMNH 240420, 5; AMNH 240485, 2 C&S, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

[[Genus Micralestes]] Roberts & Stewart (1976) in their work on the fishes of the lower Congo River reported the presence of two Micralestes in their collections: M. acutidens (Fig. 1A) and M. humilis (Fig. 1C). Recent collections in the region also include specimens of M. lualabae (Fig. 1D), M. stormsi (Fig. 1E) and M. holargyreus (Fig. 1B). In addition to these, a collection made in the vicinity of Inga revealed the presence of a population of diminutive alestid that appears most closely to resemble Micralestes but that are not assignable to any described Micralestes or to any other species dwarf African alestid., Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 18

Nannopetersius ansorgii - BMNH 1910.11.28: 71-80, paralectotypes, 4, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

M. occidentalis - AMNH 215533, 1, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

M. holargyreus - BMNH 1873.7.28: 19, 1, syntype; AMNH 239257, 4 C&S; AMNH 239479, 10; AMNH 239480, 3, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

Micralestes schelly, new species (Figs 1 F, 2 D, 3���6) Holotype (Fig. 5 B) AMNH 240662, male, 40.1 mm SL; Democratic Republic of Congo, Bas Congo Province, Congo River main channel near Inga at point 50 (5 �� 31.69 S 13 �� 36.47 E), R.C. Schelly et al., 26 Sept. 2002. Paratypes (Fig. 1 F, 5 B), with same data as holotype. AMNH 239518, 33.9 ��� 48.9 mm SL (24 alcoholic, 5 cleared and stained), MRAC 2007 - 26 -P- 1-2, 36.5 ��� 39.0 mm SL (2 alcoholic), MNHN 2007 - 1629, 35.3 ��� 40.1 mm SL (2 alcoholic), ZSM 33982, 39.0 ��� 44.2 mm SL (2 alcoholic), MCZ 166773, 34.6 ��� 36.5 mm SL (2 alcoholic), CU 93431, 36.9 ��� 40.0 mm SL (2 alcoholic). Diagnosis. A member of a clade of small alestid fishes characterized by the combination of the absence of a supraorbital bone, and the presence of a deep-lying midlateral stripe extending along the body onto the caudal peduncle, a band of chromatophores above the anal fin, and a small pair of inner row symphyseal teeth on the dentary. Micralestes schelly is distinguished from all putative congeners in having an elevated vertebral count of 38 ��� 40 (mean 39) versus 34 ��� 36 (mean 35) vertebrae. Additionally the species is characterized by the presence of 4���6 outer row premaxillary teeth with a majority of specimens (23 of 40) with only four outer row teeth implanted in an alternating pattern with respect to the anterior inner row premaxillary teeth. Mature males are further diagnosed by live coloration, which is dominated by a broad, blue-green iridescent midlateral band extending from behind the opercle to the base of the caudal fin, and by a marked expansion of the band of black chromatophores above the anal fin. Description. Based on the holotype and 39 paratypes. See Figs. 5 and 6 for general appearance, and Table 1 for summary of morphometric and meristic data. Diminutive species, maximum observed size 48.9 mm SL. Relatively deep bodied, somewhat laterally compressed with greatest body depth at, or a little in front of, dorsal-fin origin. Dorsal body profile more-or-less smoothly convex to caudal peduncle, less strongly so in mature males; ventral profile markedly convex to anal-fin insertion. Caudal peduncle slightly longer than deep. Mouth terminal, gape not reaching beyond level of anterior margin of eye. Eye moderately large, flanked by adipose membrane extending over snout to level of nostril and posterodorsally over postorbital region. Nostril large and prominent; nasal and antorbital bones greatly reduced in size (Fig. 2 D). Teeth. Stout tri- or quadri-cuspid teeth in outer row on premaxillae variable in number; majority of individual have two teeth on either premaxilla (23 of 40 specimens), 13 specimens have two teeth on one side and three teeth contralaterally, and four specimens have three teeth on both premaxillae. When only two teeth are present each is positioned opposite interspaces between and alternating with, anterior inner row teeth (Fig. 3 A). Four inner row teeth on each premaxilla, most with one large central cusp and two or three minor cusps on either side, symphyseal teeth often with single minor cusp on medial face. Four outer row teeth on contralateral dentaries, each with large central cusp and two or three minor cusps on either side. A single pair of small, conically recurved, symphyseal inner row teeth on lower jaw invariably present (Fig. 3 B). Fins. Dorsal-fin rays ii, 6���7 (total rays, 8���9), anal-fin rays iii, 16���17 (total rays 19���20). Origin of dorsal fin at, or slightly behind, vertical through pelvic-fin origin. Marked sexual dimorphism in morphology of anal fin (see Figs. 4, 5). However, unlike condition in Rhabdalestes, Hemigrammopetersius and Virilia (Stiassny and Schaefer, 2005; Zanata and Vari, 2005) there is no posterior curvature or hypertrophy of third unbranched anterior ray of mature males (Fig. 4 C). Squamation. Scales in longitudinal series 26���28 (mean 27) to caudal fin flexure, 1���3 smaller scales continuing over caudal fin base, 4.5 transverse scales between lateral line and dorsal-fin origin, 2.5 transverse scale rows between lateral line and pelvic-fin insertion. Lateral line complete, with 25���29 canal-bearing scales to point of hypural flexure, 2���4 smaller pored scales continuing over caudal-fin base. Total number of gill rakers on first gill arch 18���22 (mean 19). Total number of vertebrae 38���40 (mean 39). Color in alcohol. Base body coloration yellowish brown dorsally and laterally, yellow-orange ventrally. A darkly pigmented, deep-lying midlateral stripe extends from posterior margin of opercle to base of caudal fin. Well-marked band of dark melanophores present above anal fin. Pectoral and pelvic fins pale yellow. Adipose fin tipped in black. Dorsal and caudal fins somewhat dusky. Anal fin of females dusky proximally, in males pigmentation is somewhat expanded distally in posterior portion of fin. Color in life. Recently two male specimens have been collected from the type locality and live coloration recorded (Fig. 6). In life a broad, blue-green iridescent midlateral band covers the lateral flanks and tail from behind the opercle to the base of the caudal fin. This iridescent band overlies and obscures the deep lying midlateral stripe evident in preserved specimens (Fig. 5). Above and below the midlateral band the body is silvery white. Numerous melanophores are present on the head and opercle, and scattered over the body with a concentration around lateral scale margins. An expanded band of black melanophores reaching to the lateral line is present above anal fin. Dorsal fin and pectoral fins are dusky gray; adipose fin is pale gray with a dark distal margin. Caudal fin is dusky gray at its base with a median dark band extending to mid-fork, distally the fin is dusky gray and medially each fin fork is deep crimson red. Anterior and distal margins of the anal fin are white, while the remainder of the fin is jet black. Pelvic fins are white. Iris is silvery white with a small red patch dorsally. Unfortunately no female specimens were collected during a recent site visit and female life coloration remains unknown. Geographical distribution. Known only from the type locality in Bas Congo Province, at Point 50 on the Congo River main channel near Inga, Democratic Republic of Congo (5 �� 31.69 ���S 13 �� 36.47 E). Specimens were collected with cast nets in a complex, partially protected riffle habitat adjacent to rapids (Fig. 7). A smallunnamed stream enters the Congo River at this point and supports a patch of forest in the draw between two steep, mostly-bare hills. Micralestes schelly was collected over a sand and gravel substrate in the main channel amongst large rock slabs of up to 4 m high thrusting upward at angles of 60���70 degrees, in pools up to 2 m in depth. At this site water depth and flow is highly variable due to water surges every 5���10 minutes resulting in depth fluctuations in excess of half a meter. Etymology. Named for our colleague and the intrepid collector of the type series, Robert C. Schelly. Discussion. Recent collections in the region allow us to document the presence of six Micralestes in the stretch of the lower Congo River from Pool Malebo to Boma near the river���s mouth, and as an aid for field identification we provide here an illustrated key to those species. 1 A Teeth with numerous small cusps, first inner row premaxillary tooth with 10���12 cusps (Key Fig. 1 A). Inner row tooth pair on dentary usually multicuspid (Key Fig. 3 A). Dorsal fin with distinctive black apical patch (Key Fig. 2 A).................................................................................................................. M. acutidens 1 B Teeth with fewer cusps, first inner row premaxillary tooth with 6���8 cusps (Key Fig. 1 B). Inner row tooth pair on dentary invariably unicuspid (Key Fig. 3 B). Dorsal fin without black apical patch (Key Fig. 2 B)................................................................................................................................................................ 2 2 A 23���28 scales in longitudinal series from opercle to point of caudal flexure (Key Fig. 2 A)........................ 3, Published as part of Stiassny, Melanie L. J. & Mamonekene, Victor, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo, pp. 17-29 in Zootaxa 1614 on pages 21-25, DOI: 10.5281/zenodo.179053, {"references":["Stiassny, M. L. J. & Schaefer, S. A. (2005) Rhabdalestes aeratis, new species (Characiformes: Alestidae): first occurrence of the genus from the Middle Congo River basin. Ichthyological Exploration of Freshwaters, 16 (3), 271 - 278.","Zanata, A. M. & Vari, R. P. (2005) The family Alestidae (Ostariophysi, Characiformes): a phylogenetic analysis of a trans-Atlantic clade. Zoological Journal of the Linnean Society, 145, 1 - 144."]}

M. fodori - MRAC 140901, 1, holotype, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

M. stormsi - BMNH 1902.4.14: 28-31, syntypes, 3; AMNH 239197, 5; AMNH 238440, 5; AMNH 238437, 4 C&S, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

Rhabdalestes sp.- AMNH 227602, 18, 1 C&S, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

B. poptae - AMNH 240385, 5, 1 C&S, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

R. rhodesiensis - AMNH 50894, 2, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

M. elongatus - AMNH 215347, 8, 1 C&S, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

R. septentrionalis - AMNH 230605, 10, 5 C&S, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

A. hilgendorfi - AMNH 240421, 3, 1 C&S, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

M. lualabae - MNHN 1967-0668, paratypes, 2; AMNH 5805, 10, 2 C&S; AMNH 238386, 3, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19

M. comoensis - AMNH 097605, 4, Published as part of Melanie L. J. Stiassny & Victor Mamonekene, 2007, Micralestes (Characiformes, Alestidae) of the lower Congo River, with a description of a new species endemic to the lower Congo River rapids in the Democratic Republic of Congo., pp. 17-29 in Zootaxa 1614 on page 19