Fossil record of a Characiform in the Monte Hermoso Formation (lower Pliocene), Buenos Aires, Argentina. Palaeobiogeographical implications

BOGAN, SERGIO; AGNOLIN, FEDERICO; MIRANDE, JUAN MARCOS

Comptes Rendus Palevol

Académie des sciences

Lugar: Paris; Año: 2021 vol. 20 p. 49 - 55

The fossil record of fishes from the Farola de Monte Hermoso locality (lower Pliocene) in the southernBuenos Aires province, Argentina, shows an unusual composition. The locality at the southern bound-ary of the Brazilian Ichthyogeographic Realm. However, its fossil record is composed of fossil fishesthat are not necessarily related to Brazilian lineages, namely indeterminate siluriforms, trichomycteridcatfishes, and percomorphaceans. The aim of the present contribution is to describe and report forthe first time isolated specimens belonging to Characidae fishes. In the Pampean region the fossilrecord of characids is restricted to Oligosarcus Günther, 1864 sp. from the late-middle Pleistocene.The present finding fills a temporal gap between the Paleogene and Quaternary reports and indicatesthat Brazilian fish lineages were present in the area by early Pliocene times, and may constitute anindirect evidence of the evolution of the basins in the southern Pampean Area.