Eekaulostomus cuevasae gen. and sp. nov., an ancient armored trumpetfish (Aulostomoidea) from Danian (Paleocene) marine deposits of Belisario Domínguez, Chiapas, southeastern Mexico

Abstract

Eekaulostomus cuevasae gen. and sp. nov. is described and identified here as a new member of the superfamily Aulostomoidea. The single specimen known of this species is part of a newly fossil assemblage collected in the marine sediments belonging to the early Paleocene Tenejapa-Lacandon geological unit, exploited in the Belisario Dominguez quarry, near Palenque town, State of Chiapas, southeastern Mexico. E. cuevasae represents the oldest aulostomoid as far known and the first fossil species of this superfamily collected in America. E. cuevasae differs from other aulostomoids in the presence of two spines preceding the soft rays of both dorsal and anal fins; the star-like scales covering the entire body and part of the snout; as well as the relative large number of principal rays in the caudal fin. The recognition of E. cuevasae as the stem group of Aulostomoidea increases the temporal and geographic distribution of this superfamily up to Danian and within the Caribbean region, when a large part of Chiapas was under the sea after the Cretaceous-Tertiary mass extinction event. This finding also provides evidences suggesting the membership of Aulostomoidea within the order Gasterosteiformes, in which the scutes covering the trunk and the robust spines in unpaired fins are recurrent features.