Neogene tropical sea catfish (Siluriformes; Ariidae), with insights into paleo and modern diversity within northeastern South America

摘要

Herein we describe five new fossil species of the catfish family Ariidae: dagger Amphiarius paleoorinocoensis, dagger Ariopsis ariopsilus, dagger Bagre urumacoensis, dagger Sciades latissimum and dagger Sciades peregrinus from the late Miocene Urumaco Formation in Venezuela, South America. These identifications were based on comparison of morphological characters between the fossil skulls and the skulls of extant specimens from tropical America. The extant ariids from the Atlantic plume of the Orinoco-Amazon rivers reveal close taxonomic relationship to the fossil species. fAmphiarius paleoorinocoensis n. sp. and dagger Aspistor ver-umquadriscutis are closely related to Amphiarius rugispinis, Amphiarius phrygiatus and Aspistor quadriscutis, species endemic to areas under the influence of the Orinoco-Amazon plume. Another genus whose extant species are almost exclusively found in this region of the Atlantic is Sciades. Nevertheless, dagger Sciades latissimus n. sp. and dagger Sciades peregrinus n. sp., are closely related with Sciades dowii, found in the Pacific. This condition supports the extinction of Sciades dowii lineage in the Atlantic. The fossil dagger Ariopsis ariopsilus n. sp. shares many characters with extant species of the genus, which does not occur in the Amazon delta and which has no representative species in the Atlantic plume. The close relationship of dagger Bagre urumacoensis n. sp. to Bagre aff. marinus suggests a marine paleoenvironment with average to higher salinities. These new fossil catfish specimens from the Urumaco Formation suggest that they are ancestral lineages from both the Orinoco-Amazon Atlantic plume influence area (Aspistor and Amphiarius) and the Caribbean-Western Pacific (Ariopsis), and extinct lineage of Sciades from the Atlantic. (C) 2018 Elsevier Ltd. All rights reserved.