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

Resumen

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.