Abstract

PARAMO-FONSECA, María Eurídice; BENAVIDES-CABRA, Cristian David  and  GUTIERREZ, Ingry Esmirna. A new large Pliosaurid from the Barremian (Lower Cretaceous) of Sáchica, Boyacá, Colombia. Earth Sci. Res. J. [online]. 2018, vol.22, n.4, pp.223-238. ISSN 1794-6190.  https://doi.org/10.15446/esrj.v22n4.69916.

A new pliosaurid specimen found in the Barremian beds of Sáchica, a town near Villa de Leiva, representing the more complete skeleton found in the region is described here. After a detailed study of its morphological characteristics, it is evident that the new specimen represents a new genus and species of brachauchenine pliosaurid from Central Colombia that we name Sachicasaurus vitae gen. et sp. nov. Sachicasaurus is a large derived brachauchenine (almost 10 m in length) characterized by two autopomorphic characters: a very short mandibular symphysis ending at the mid length of the fourth mandibular alveoli and reduced number of mandibular teeth (17-18). It is also distinguished by the following combination of characters: skull exceeding two meters in length, lateral expansion of the maxilla posterior to the premaxilla-maxilla suture, presence of caniniform teeth, dental sequence showing only two non-contiguous largest teeth (D4, Mx1), pineal foramen in a very anterior position, vomer bifurcated posteriorly, palatines separated in the midline by the pterygoids, slender hyoid bones, 12 cervical vertebrae, cervical centra without dorsal but with ventral foramina, single rib facet in all cervical centra, at least 37 pre-sacral vertebrae, and ilium with a long posterior projection. The morphological comparisons and the cladistic analysis show the new specimen as a derived brachauchenine with evident phylogenetic proximity to the Colombian species “Kronosaurus” boyacensis from the upper Aptian, suggesting that they could belong to the same genus.

Keywords : Pliosauridae; Brachaucheninae; Lower Cretaceous; Barremian; Sáchica; Colombia.

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