The Paleozoic and Mesozoic vertebrate record of Venezuela: An overview, summary of previous discoveries and report of a mosasaur from the La Luna Formation (Cretaceous)

Abstract

Most reports of Paleozoic and Mesozoic vertebrates from Venezuela are anecdotical, with few detailed descriptions of mostly 'fish' groups. Synapsids (e.g., mammals) are totally unknown, and dinosaurs are only reported from the La Quinta Formation. At least 14 formally recognized geological formations contain fossil vertebrates, most from the Central and Western parts of the country. In the Devonian there is a significant contrast between the vertebrates of Venezuela and Colombia and those of more southern parts of South America. Marine reptiles are present in a few localities in western Venezuela, and are very fragmentary, with one exception. A mosasaur from the Cretaceous La Luna Formation, reported here for the first time, is the most complete vertebrate (tetrapod) from the Cretaceous of Venezuela, and includes a partial skull and a few postcranial remains.

Equatorial pliosaurid from Venezuela marks the youngest South American occurrence of the clade

“…A high diversity of lamniform sharks (at least 12 taxa in five clades, eight of which are anacoracids), have been described from the La Luna Formation, representing active pelagic predators and scavengers of large vertebrates and small nektobenthic predators feeding on small bony fish and invertebrates 40 . The new plesiosaur specimen adds to the diversity of large marine reptiles from the La Luna Formation and represents the largest predator described from the strata so far ( 74,75 , Supplementary Table 1).…”

An enigmatic aquatic snake from the Cenomanian of Northern South America

“…Although anoxic-dysoxic conditions prevailed on the seafloor of the basin ( Méndez, 1981 ; Macellari & De Vries, 1987 ; Tribovillard et al, 1991 ; Erlich et al, 1999 ), the presence of ammonites ( Renz, 1959 ; Renz, 1982 ), reptiles ( Lunaophis aquaticus ), and abundant fishes provides evidence of well-oxygenated surface waters, indicating that the Aguada Member environment was characterized by a stratified water column. In addition, other chondrichthyans, bony fishes and marine reptile have also been found throughout the La Luna Formation ( Weiler, 1940 ; Moody & Maisey, 1994 ; Casas & Moody, 1997 ; Sánchez-Villagra, Brinkmann & Lozsán, 2008 ; Carrillo-Briceño, 2009 ; Carrillo-Briceño, 2012 ).…”

Primer registro de Xiphactinus Leidy, 1870 (Teleostei, Ichthyodectiformes) en el Cretácico Superior de América del Sur (Formación La Luna, Venezuela)

“…Aún cuando los estudios sobre peces óseos del Cretácico de Venezuela son escasos (Odreman & Medina, 1984;Moody & Maisey, 1994;Sánchez-Villagra et al, 2008;Carrillo, 2009), la presencia de peces Ichthyodectiformes en este país incluye el reporte de ejemplares conferidos a Ichthyodectes (Moody & Maisey, 1994) y Cladocyclus Agassiz, 1841 (Aguilera & Lundberg, 2009, Aguilera, 2010, recolectados en las calizas del Aptiano de la Formación Apón, en la Sierra de Perijá, al Oeste de Venezuela. Cladocyclus es un Ichthyodectiforme gondwánico ampliamente documentado en las formaciones Crato y Santana también presente en las cuencas de Araripe, Parnaíba y Sergipe-Alagoas (Brito & Yabumoto, 2011) recientemente encontrado en los yacimientos marinos del Cenomaniano Tardío-Turoniano Temprano de Gara Sbaa, en Marruecos (Martill et al, 2011).…”