Freshwater fishes of Sierra Leone and Liberia : annotated checklist and distribution

A partir des collections déposées dans les muséums d'histoire naturelle européens et dans un muséum américain, réalisées en partie par les auteurs et à partir de travaux effectués dans cette zone, une mise à jour des connaissances de la faune ichtyologique des bassins côtiers de la Sierra Leone et du Liberia est présentée. Il a été tenu compte pour la nomenclature des révisions les plus récentes. Des listes par bassin hydrographique ont été établies qui doivent servir de base à un travail d'ensemble sur la zoogéograhie des poissons d'Afrique de l'ouest. (Résumé d'auteur

A review of the systematic biology of fossil and living bony-tongue fishes, Osteoglossomorpha (Actinopterygii: Teleostei)

The bony-tongue fishes, Osteoglossomorpha, have been the focus of a great deal of morphological, systematic, and evolutionary study, due in part to their basal position among extant teleostean fishes. This group includes the mooneyes (Hiodontidae), knifefishes (Notopteridae), the abu (Gymnarchidae), elephantfishes (Mormyridae), arawanas and pirarucu (Osteoglossidae), and the African butterfly fish (Pantodontidae). This morphologically heterogeneous group also has a long and diverse fossil record, including taxa from all continents and both freshwater and marine deposits. The phylogenetic relationships among most extant osteoglossomorph families are widely agreed upon. However, there is still much to discover about the systematic biology of these fishes, particularly with regard to the phylogenetic affinities of several fossil taxa, within Mormyridae, and the position of Pantodon. In this paper we review the state of knowledge for osteoglossomorph fishes. We first provide an overview of the diversity of Osteoglossomorpha, and then discuss studies of the phylogeny of Osteoglossomorpha from both morphological and molecular perspectives, as well as biogeographic analyses of the group. Finally, we offer our perspectives on future needs for research on the systematic biology of Osteoglossomorpha

Freshwater fishes of Sierra Leone and Liberia : annotated checklist and distribution

A partir des collections déposées dans les muséums d'histoire naturelle européens et dans un muséum américain, réalisées en partie par les auteurs et à partir de travaux effectués dans cette zone, une mise à jour des connaissances de la faune ichtyologique des bassins côtiers de la Sierra Leone et du Liberia est présentée. Il a été tenu compte pour la nomenclature des révisions les plus récentes. Des listes par bassin hydrographique ont été établies qui doivent servir de base à un travail d'ensemble sur la zoogéograhie des poissons d'Afrique de l'ouest. (Résumé d'auteur

Morphological and electrophysiological field observations on electric freshwater fish of the genus Mormyrops Müller 1843 (Teleostei: Mormyridae) from West and southern Africa

Different specimens of Mormyrops anguilloides (Linnaeus 1758) were reported to display electric organ discharge (EOD) pulses of either initially head-positive or initially negative polarity, a hypothetical sex difference that has not been substantiated to date. The morphology and EODs of M. anguilloides of both sexes and a sexually mature size from the Comoé and Bandama rivers, Côte d'Ivoire, and the Lower and Middle Zambezi, Mozambique, displayed initially positive EODs. The morphologically similar M. breviceps Steindachner 1895 of both sexes and a sexually mature size from the Bandama River displayed initially head-negative EODs of biphasic waveform and long duration (0.93–1.15 ms) in the very-low-frequency spectral range. Mormyrops anguilloides from the Comoé and Bandama rivers were differentiated in caudal peduncle depth and in EOD waveform, pulse duration and spectral energy content. The former samples displayed a biphasic, lower-frequency EOD pulse of up to 0.42 ms duration, the latter a tetraphasic, high-frequency EOD of up to 0.33 ms. It is suggested that reports of EODs of both polarities in M. anguilloides indicate the presence of an unrecognised species

Differentiation in morphology and electrical signalling in four species of para- and sympatric Marcusenius (Teleostei: Mormyridae) from Côte d’Ivoire, West Africa

Marcusenius Gill, 1862 species were sampled from the Bandama River and the Comoé River in Côte d’Ivoire, West Africa. Marcusenius gracilis sp. nov. was differentiated from M. senegalensis (Steindachner, 1870), Marcusenius ussheri (Günther, 1867) and M. furcidens (Pellegrin, 1920) in electric organ discharges (EOD), and morphologically from all other West African congeners. Principal component analysis showed significant morphological differentiation among the four Ivorian species. Principal component 1 was loaded most strongly by characters affecting swimming power and manoeuvrability. The morphologically most similar pair, M. furcidens and M. gracilis sp. nov., are distinguished by their EOD waveforms and a sexual dimorphism in the anal fin base in the latter not present in the former. M. ussheri is distinguished by a sexual dimorphism in its EOD waveform not observed in the other three species. This system is an opportunity to study how far the fine-tuning of character displacement among syntopic species can go

Effects of Co-solvents on Reactions Run under Micellar Catalysis Conditions

The impact of varying percentages of an organic solvent added to reactions run in aqueous nanomicelles as the reaction medium has been investigated. Issues such as rates of reaction, percent conversion, and yield, as well as various practical aspects (e.g., effect on stirring, etc.), are discussed, leading to an operationally simple method for the general improvement of potentially problematic systems across a broad range of reaction types, in particular for reactions run at scale

Fish-AMAZBOL : a database on freshwater fishes of the Bolivian Amazon

The Bolivian part of the Amazon Basin contains a mega diverse and well-preserved fish fauna. Since the last decade, this fish fauna has received an increasing attention from scientists and the national authorities as fishes represent one of the most important sources of proteins for local human communities. However, this fish fauna still remains poorly documented. Here, we present a database for fishes from the Bolivian Amazon. To build the database, we conducted an extensive literature survey of native and non-native (exotic) fishes inhabiting all major sub-drainages of the Bolivian Amazon. The database, named Fish-AMAZBOL, contains species lists for 13 Amazonian hydrological units, covering 100% of the Bolivian Amazon and approximately 65% (722,137 km(2)) of the all territory. Fish-AMAZBOL includes 802 valid species, 12 of them being non-native, that have been checked for systematic reliability and consistency. To put this number in perspective, this represents around 14% of the all Neotropical ichthyofauna and around 6% of all strictly freshwater fishes inhabiting the planet. This database is currently the most comprehensive database of native and non-native fish species richness available so far for the Bolivian Amazon

Unexpected fish diversity gradients in the Amazon basin

WOS:000491128800037International audienceUsing the most comprehensive fish occurrence database, we evaluated the importance of ecological and historical drivers in diversity patterns of subdrainage basins across the Amazon system. Linear models reveal the influence of climatic conditions, habitat size and sub-basin isolation on species diversity. Unexpectedly, the species richness model also highlighted a negative upriver-downriver gradient, contrary to predictions of increasing richness at more downriver locations along fluvial gradients. This reverse gradient may be linked to the history of the Amazon drainage network, which, after isolation as western and eastern basins throughout the Miocene, only began flowing eastward 1-9 million years (Ma) ago. Our results suggest that the main center of fish diversity was located westward, with fish dispersal progressing eastward after the basins were united and the Amazon River assumed its modern course toward the Atlantic. This dispersal process seems not yet achieved, suggesting a recent formation of the current Amazon system