Occurrence of a tylosaurine mosasaur (Mosasauridae; Russellosaurina) from the Turonian of Chihuahua State, Mexico

Abstract

A new mosasaur specimen was discovered in the Ojinaga Formation (Turonian) in Chihuahua, Mexico. It is described here based on an incomplete, slightly deformed skull. Comparative analysis reveals features from the parafamily Russellosaurinae, especially the genus Tylosaurus. Some features as the "V" shaped skull, well developed rostral process, 12 to 13 dentary and maxillary teeth, shape of premaxilla-maxilla suture, and similar proportions of mandible and quadrate bone are characteristics of Tylosaurus, and are similar to T. proriger and T. nepaeolicus, but the absence of an infrastapedial process indicates it is most closely related to T. kansasensis.Keywords: Mosasauridae, Chihuahua, Ojinaga Formation, Tylosaurus. Resumen Un nuevo espécimen de mosasaurio fue descubierto en la Formación