Peces Criollos - Freshwater Fishes of Argentina Peces Criollos - Freshwater Fishes of Argentina
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Megaleporinus obtusidens comb.nov. from Leporinus

new combination:
Megaleporinus obtusidens (Valenciennes, 1837) from Leporinus

published in:
Ramirez, J.L., J.L.O. Birindelli & P.M. Galetti (2017):
A new genus of Anostomidae (Ostariophysi: Characiformes): Diversity, phylogeny and biogeography based on cytogenetic, molecular and morphological data.
Molecular Phylogenetics and Evolution 107: 308-323

abstract (from publication):
A new genus of Anostomidae (Characiformes) is described to include ten valid extant species previously classified in Leporinus or Hypomasticus and distributed throughout most major river basins in South America: L. brinco, L. conirostris, L. elongatus, H. garmani, L. macrocephalus, L. muyscorum, L. obtusidens, L. piavussu, L. reinhardti, and L. trifasciatus. The monophyly of Megaleporinus is well-supported in a phylogenetic analysis based on two mitochondrial and three nuclear genes, as well as its sister group relationship to Abramites. Megaleporinus is diagnosed by having the exclusive combination of three unicuspid teeth on each premaxillary and dentary bone and a color pattern composed of one to four dark midlateral blotches. Additional distinguishing features and possible synapomorphies include a unique ZZ/ZW sex chromosome system confirmed for six congeners and a drumming apparatus wherein the first rib is elongated and associated with hypertrophied intercostal muscles, which was confirmed for three congeners as exclusive to mature males. Furthermore, our study identified at least four undescribed cryptic species, emphasizing the need for further taxonomic work and genetic analyses. A time-calibrated phylogenetic and biogeographical analysis of the new genus suggests that speciation in the proto-Amazon-Orinoco lineage was primarily driven by paleogeographic processes, such as the formation of the Orinoco and Tocantins basins. Dispersal and diversification of the genus in coastal basins draining the Eastern Brazilian Shield appears to have been facilitated by connections between paleo-basins during low sea level periods and headwater captures between coastal and inland watersheds. The present contribution demonstrates the importance of integrating data from morphology, DNA sequences and cytogenetics to advance the taxonomy and systematics of any complex species group.

Oligosarcus pintoi - first record from Argentina

Moenkhausia bonita - first record from Paraguay

Potamoglanis johnsoni comb.nov. from Trichomycterus

Schizodon altoparanae - first record from Paraguay

Pinirampus argentina comb.nov. from Megalonema

Farlowella azpelicuetae sp.nov. from Argentina

Jenynsia sulfurica sp.nov. from Argentina

Zungaro jahu - Paulicea gigantea is a jr. synonym

CLOFFAR - update 6

Steindachnerina nigrotaenia - resurrected from synonymy of S. brevipinna

Steindachnerina insculpta - not a species from Argentina

Hypostomus cordovae revalidated from synonymy with H. paranensis

Hypostomus spiniger revalidated from synonymy with H. commersoni

Moenkhausia bonita - first record from Argentina

Moenkhausia intermedia - not a species from Argentina

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