Molecular and morphological evidence revalidates Acrobrycon tarijae (Characiformes, Characidae) and shows hidden diversity

By

Briñoccoli, Yanina F.
Bogan, Sergio
Arcila, Dahiana
Rosso, Juan J
Mabragaña, Ezequiel
Delpiani, Sergio M.
De Astarloa, Juan Martín Díaz
Cardoso, Yamila P.

Type

Article

Date of Publication

2022-3-31

Original Publication

ZooKeys

Volume

1091

Pages

99--117

Subjects

Endorheic , Freshwater fishes , La Plata River basin , mitochondrial DNA , Stevardiinae

Contributed by

Pensoft Publishers

Language

English

Published by

Sofia, Bulgaria Pensoft Publishers

Identifiers

DOI: https://doi.org/10.3897/zookeys.1091.73446

 

Abstract

We conducted a revision of the Neotropical genus Acrobrycon. A previous study synonymized the species, A. ipanquianus, distributed from the western portion of the Amazon River to the north-western region of the La Plata River Basin, and A. tarijae, with type locality in the Lipeo River in Bolivia. We revisited this result by collecting new morphometric, meristic, and genetic data (COI mitochondrial gene) for 24 individuals distributed along La Plata River Basin in Argentina, and discussed our results in the context of multiple biogeographic processes of isolation in that basin. Our results revealed a more complex history of diversification and geographic distribution across Acrobrycon species than previously suspected, probably associated with multiple biogeographic processes of isolation in La Plata River Basin. We present new evidence that led us to reconsider the validity of A. tarijae, which is distinguishable from A. ipanquianus by the number of vertebrae (37–39 vs. 41–42) and pleural ribs (12–13 vs. 14). These results were also supported by our molecular analyses that revealed a genetic divergence >4% between A. ipanquianus and A. tarijae. We also identified two main genetic clusters within A. tarijae: the first cluster consisted of specimens from the Bermejo, Pilcomayo, Itiyuro and Juramento river basins (northern Argentina); and the second cluster included specimens from the southernmost basins, such as the Salí River in Tucumán, Cuarto River in the province of Cordoba and the Quinto River in the province of San Luis. Our results suggest that the genetic structure observed in A. tarijae is the result of the type of drainage (endorheic vs. exorheic) and geographical distance.