Stratigraphic distribution of marine vertebrates of the arcillolitas abigarradas member (Paja Formation) from the Villa de Leiva – Sáchica - Sutamarchán region, Boyacá, Colombia

Abstract

The Villa de Leiva – Sáchica - Sutamarchán region is the most prolific locality for Early Cretaceous marine vertebrates in Colombia and one of the richest in these vertebrates in the world. All of these vertebrates come from beds of the Barremian-Aptian Arcillolitas abigarradas Member of the Paja Formation. Although many of the specimens have already been taxonomically studied, no publications have discussed their stratigraphic position and distribution within the Barremian-Aptian interval. Herein, we provide, for the first time, detailed stratigraphic information for the majority of the Barremian-Aptian marine vertebrates of the Villa de Leiva – Sáchica - Sutamarchán region reported so far. Based on 10 stratigraphic sections described in the several specimens finding sites, together with biostratigraphic information associated with specimens of imprecise geographical origin, we determined the stratigraphic provenance of 26 marine vertebrate specimens. It was also possible to refine the stratigraphic provenance of some specimens including the holotypes of Muiscasaurus catheti, “Kyhytysuka” sachicarum, and Protolamna ricaurtei whose stratigraphic origin was not previously specified beyond the Arcillolitas abigarradas Member. The data obtained allowed us to identify four vertebrate assemblages representing coeval faunas within the Barremian-Aptian interval, two from the Barremian and two from the upper Aptian.