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Chalceus guaporensis is an endemic fish to the upper Madeira River whereas C. epakros is widespread in many rivers of the central and lower portions of the Amazon Basin, middle and upper Orinoco River Basin, the Essequibo River in Guyana and in the Nanay River in northern Peru. According to literature, both species do not occur in syntopy. We carried out ichthyological surveys along the Madeira River Basin and its rapids, and data on abundance, diet and habitat use were obtained for both species. Chalceus guaporensis and C. epakros are morphologically similar, occupying floodplain habitats and exploiting similar food resources. The former predominated upstream from the Jirau Fall, whereas the latter had most of its abundance bellow the last fall of the Madeira River; both species co-occurred along part of the rapids stretch and in the Machado River, but with strongly uneven abundances. This pattern may have developed in the past by speciation regarding the presence of the falls, while co-occurrence of the two species seems to be regulated by competitive interactions or maintained by slight differences in environmental requirements nowadays. The recent disruption of the Madeira River by two run-of-river dams built in cascade submerged a large portion of the rapids stretch and substituted it by semi-lenthic habitats created by the dam reservoirs, together with the construction of a fish passage. These environmental changes may allow the invasion of the upper reaches of the Madeira River by C. epakros, and disturb the population of endemic C. guaporensis. RESUMO Chalceus guaporensis é descrita como uma espécie endêmica do alto rio Madeira, enquanto C. epakros está amplamente distribuída em rios das porções central e inferior da bacia Amazônica, no médio e alto rio Orinoco, e nos rios Essequibo, na Guiana, e Nanay, no norte do Peru. A literatura não registra essas espécies como sintópicas. Expedições ictiológicas realizadas ao longo do rio Madeira e suas corredeiras nos deram a oportunidade de registrar a presença, abundância, habitat e dieta utilizadas por essas espécies. Chalceus guaporensis e C. epakros são muito similares morfologicamente, ocupam habitats inundáveis e apresentam espectro alimentar semelhante. A primeira espécie predominou a montante da cachoeira Jirau, enquanto que a segunda teve a maior parte de sua abundância registrada à jusante das cachoeiras do rio Madeira. Ambas espécies coocorreram ao longo de parte do trecho de corredeiras e no rio Machado, mas com abundâncias muito desiguais. Esse padrão pode ter se desenvolvido no passado, por especiação, em função da presença das corredeiras, enquanto a coocorrência das duas espécies parece ser regulada por interações competitivas ou mantida por diferenças sutis em requisitos ecológicos no tempo atual. O recente barramento do rio Madeira por duas hidrelétricas construídas em cascata submergiu uma grande porção do trecho de corredeiras e o substituiu por habitats semilênticos, criados pelos reservatórios das hidrelétricas a fio d’água, juntamente com a construção de uma passagem para peixes. Essas alterações ambientais podem permitir que C. epakros invada o trecho superior da bacia do rio Madeira, com possíveis impactos negativos sobre a população da espécie endêmica C. guaporensis.

Made available in DSpace on 2018-11-26T17:42:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-12-12 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Hepsetidae is a small fish family with only the genus Hepsetus, with six described species distributed throughout the South, Central and Western regions of Africa, showing a close relationship with the Alestidae and some Neotropical fish families. However, no cytogenetic information is available for both Hepsetidae and Alestidae species, thus preventing any evolutionary comparative studies at the chromosomal level. In the present study, we are providing new cytogenetic data for Hepsetus odoe, including the standard karyotype, C-banding, repetitive DNAs mapping, comparative genomic hybridization (CGH) and whole chromosome painting (WCP), providing chromosomal patterns and subsidies for comparative cytogenetics with other characiform families. Both males and females H. odoe have 2n = 58 chromosomes (10m + 28sm + 20st/a), with most of the C-band positive heterochromatin localized in the centromeric and subtelomeric regions. Only one pair of chromosomes bears proximal 5S rDNA sites in the short arms, contrasting with the 18S rDNA sequences which are located in the terminal regions of four chromosome pairs. Clear interstitial hybridization signals are evidenced for the U1 and U2 snDNA probes, but in only one and two chromosome pairs, respectively. Microsatellite motifs are widely distributed in the karyotype, with exception for the (CGG)(10), (GAA)(10) and (GAG)(10) probes, which highlight conspicuous interstitial signals on an unique pair of chromosomes. Comparative data from conventional and molecular cytogenetics, including CGH and WCP experiments, indicate that H. odoe and some Erythrinidae species, particularly Erythrinus erythrinus, share similar chromosomal sequences suggesting some relatedness among them, although bearing genomic specificities in view of their divergent evolutionary histories. Univ Fed Sao Carlos, Dept Genet & Evolucao, Sao Carlos, SP, Brazil Estado Educ Mato Grosso Seduc MT, Cuiaba, Brazil Univ Estadual Paulista, Inst Biociencias, Dept Morfol, Botucatu, SP, Brazil Royal Museum Cent Africa, Sect Vertebrates Ichthyol, Tervuren, Belgium Adamawa State Univ, Dept Fisheries & Aquaculture, Mubi, Nigeria Univ Hosp Jena, Inst Human Genet, Jena, Germany Univ Estadual Paulista, Inst Biociencias, Dept Morfol, Botucatu, SP, Brazil CNPq: 304992/2015-1 CNPq: 401575/2016-0 FAPESP: 2016/21411-7 FAPESP: 2016/17556-0 FAPESP: 2017/08471-3 FAPESP: FAPESP 2014/26508-3 FAPESP: CNPq 306054/2006-0

Objectifs: Ce travail vise a faire le premier inventaire qualitatif et quantitatif du peuplement ichtyologique du lac de barrage d’Ayame 2. Methodologie et resultats: L’ichtyofaune a ete echantillonnee mensuellement entre Juin 2015 et Mai 2016 au moyen des filets maillants. Les donnees des peches experimentales ont ete completees par celles des peches commerciales. Au total, 40 especes de poissons incluant un Tilapia hybride ( T. zillii x T. guineensis ) et deux especes introduites ( Oreochromis niloticus et Heterotis niloticus ) ont ete recoltees. Ces especes sont reparties en 26 genres et 15 familles. Le peuplement ichtyologique est domine par les Cichlidae (35,04%), Claroteidae (28,89%) et Alestidae (24,91%). Les especes majoritaires sont Oreochromis niloticus (30,99%), Chrysichthys nigrodigitatus (17,9%) et Brycinus nurse (11,74%). Les valeurs des indices de diversite traduisent que le peuplement du milieu est diversifie. Conclusion et application des resultats: Cette etude a permis de faire le premier inventaire qualitatif et quantitatif de l’ichtyofaune du lac de barrage d’Ayame 2. Ces resultats serviront de references pour les investigations ulterieures de suivi de la faune ichtyologique et a l’elaboration de mesures adequates pour assurer une meilleure protection et une exploitation durable des ressources aquatiques de ce lac. Mots cles: Poisson, inventaire, diversite, lac de barrage d’Ayame 2, Cote d’Ivoire English Title: Preliminary data on the ichtyofauna of a west African Lake situated between two hydroelectric dams: man-made Lake Ayame 2 (Cote d’Ivoire) English Abstract Objectives: The objective of this work is to study for the first time the composition of fishes in the man-made Lake Ayame 2 situated between two hydroelectric dams. Methodology and Results: The ichthyofauna of man-made Lake Ayame 2 (South eastern of Cote d’Ivoire) was collected between June 2015 and May 2016. Fish samples were collected using gill-nets and commercial fish landings and held workshop with the local fishermen. Forty (40) species were identified in this study. The family of Cichlidae (35.04%), Claroteidae (28.89%) and Alestidae (24.91%) were dominated the fish community of man-made Lake Ayame 2. The most abundant species were Oreochromis niloticus (30.99%), Chrysichthys nigrodigitatus (17.9%) and Brycinus nurse (11.74%). The values of diversity index show that the population of environment is diversified. Conclusion and application of findings: This study allowed to make an inventory of the ichthyofauna of manmade Lake Ayame 2 for the first time and to characterize the population. These results will be references to follow through ichthyofauna and to take appropriate steps to avoid losses in aquatic biodiversity. Keywords: Fish, inventory, diversity, man-made Lake Ayame 2, Cote d’Ivoire

Renewed research at the early Miocene fossil site of Bukwa in northeastern Uganda has resulted in new fossil finds, including fish, with representatives of two families, Cichlidae and Alestidae. Although the two families were previously briefly reported from Bukwa, we here give a more detailed account of the fishes based on newly collected material. The cichlid material, mainly composed of vertebrae, can be tentatively assigned to one or more species of Pseudocrenilabrinae. The alestid material, comprising a diversity of teeth, likely represents several different species of Alestes, Brycinus, and/or Bryconaethiops. Although the ichthyofaunal diversity of Bukwa is low, the fishes are important for indicating the paleoenvironment and hydrographic connections of Bukwa. The early Miocene was a critical time for African faunas, because it was during this time that the Afro-Arabian and Eurasian plates came into contact with one another, ending the long isolation of Africa, which, along with rifting in E...

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.

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

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.

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.

Phylogenetic relationships among fishes from ostariophysan orders, characiform fami? lies, and serrasalmin genera (e.g., "piranhas") were examined using partial mitochondrial ribo? somal DNA sequences of the 12S and 16S genes. Phylogenetic information content of these se? quences was assessed at three levels of taxonomic inclusiveness by analyzing the patterns of nucleotide substitution using secondary structure models. Conserved and variable regions were identified, mapped onto the structural models, and compared at increasing levels of taxonomic divergence. In general, loop regions (unpaired) exhibited a higher level of variation than did stem regions (paired). A high proportion of compensatory substitutions was observed in stem regions in three data sets, suggesting strong selection to maintain the secondary structure. Saturation due to multiple substitutions was indicated by decreasing transition/transversion ratios and strong structural constraints on variation in comparisons among orders of Ostariophysi but was not obvious among familes of Characiformes and was not detected among serrasalmin genera. Reli? able phylogenetic signal successfully reconstructed relationships among serrasalmin genera. How? ever, aside from a few well-supported clades, relationships could not be reconstructed with con? fidence among characiform families and ostariophysan orders. The reciprocal monophyly of African and Neotropical characiform lineages was rejected (based on maximum likelihood ratio tests), and some support for previous hypotheses based on morphology was provided by the molecular data. The radiation of characiform fishes is discussed in a historical biogeographic context. (Biogeography; Characiformes; mitochondrial DNA; molecular phylogenetics; Ostario? physi; phylogenetic information; secondary structure.) Characiform fishes provide a prime ex? ample of the complex evolutionary and biogeographical patterns often seen in tropical and subtropical faunas. They con? stitute a group of ecologically and mor? phologically diverse fish that live in rivers and lakes in Africa and the Neotropics. The vast array of trophic specializations found among characiforms is comparable to that of cichlids and includes detritivory (mud eating), herbivory, planktivory (plankton filtering), predation, fin and scale eating, and the notorious group pre? dation of piranhas. Some species have pe? culiar morphological and physiological ad? aptations for survival in extreme hypoxic conditions commonly found in their flood? plain environments (e.g., air breathing and special membranous extensions of the lips for gaseous exchange in the surface film of the water column). Other species ("hatch