Intergeneric phylogenetic relationships in catfishes of the Loricariinae (Siluriformes: Loricariidae), with the description of Fonchiiloricaria nanodon: a new genus and species from Peru

Recent investigations in the upper Rio Huallaga in Peru revealed the presence of an intriguing species of the Loricariinae. To characterize and place this species within the evolutionary tree of the subfamily, a molecular phylogeny of this group was inferred based on the 12S and 16S mitochondrial genes and the nuclear gene F-reticulon4. The phylogeny indicated that this distinctive species was a member of the subtribe Loricariina. Given its phylogenetic placement, and its unusual morphology, this species is described as a new genus and new species of Loricariinae: Fonchiiloricaria nanodon. This new taxon is diagnosed by usually possessing one to three premaxillary teeth that are greatly reduced; lips with globular papillae on the surface; the distal margin of lower lip bearing short, triangular filaments; the premaxilla greatly reduced; the abdomen completely covered by plates, with the plates between lateral abdominal plates small and rhombic; a caudal fin with 14 rays; the orbital notch absent; five lateral series of plates; dorsal-fin spinelet absent; preanal plate present, large and solid, and of irregular, polygonal shape, the caudal peduncle becoming more compressed posteriorly for the last seven to 10 plates. (C) 2011 The Authors Journal of Fish Biology (C) 2011 The Fisheries Society of the British IslesFAPESP[2007/04701-2]All Catfish Species Inventory[NSF-DEB 0315963

Genetic landscape clustering of a large DNA barcoding data set reveals shared patterns of genetic divergence among freshwater fishes of the Maroni Basin

International audienceThe Maroni is one of the most speciose basins of the Guianas and hosts a megadiverse freshwater fish community. Although taxonomical references based on morphological identification exist for both the Surinamese and Guianese parts of the basin, there are still taxonomical uncertainties concerning the status of several species. We used COI sequences of 1,284 fish in conjunction with morphological and biogeographical evidence to assist with species delineation and discovery in order to validate and standardise the current taxonomy. This resulted in a final DNA barcode dataset of 199 fish species (125 genera, 36 families, and 8 orders; 68.86% of strictly freshwater fishes from the basin), among which 25 are new putative candidate species flagged as requiring taxonomic update. DNA barcoding delineation through BINs unveiled further cryptic diversity (230 BINs in total). To explore global genetic patterns across the basin, genetic divergence landscapes were computed for 128 species, showing a global trend of high genetic divergence between the Surinamese south‐west (Tapanahony and Paloemeu), the Guianese south‐east (Marouini, Litany, Tampok…), and the river outlet in the north. This could be explained by lower levels of connectivity between these three main areas and/or the exchange of individuals between these areas and the neighbouring basins. A new method of ordination of genetic landscapes successfully assigned species into cluster groups based on their respective pattern of genetic divergence across the Maroni Basin: genetically homogenous species were effectively discriminated from species showing high spatial genetic fragmentation and possible lower capacity for dispersal