Occurrence of a second ichthyosaur genus (Reptilia: Ichthyosauria) in the Late Jurassic Gulf of Mexico

Resumen

The forefin of the
recently excavated partial skeleton of a large ichthyosaur is here
described. The specimen comes from the upper Tithonian (Upper
Jurassic) La Caja Formation in the south of Coahuila State. The
anatomy of the forefin as well as of those currently visible parts
of the skull demonstrates it likely represents an Ophthalmosauridae,
in any case it is distinct from Ophthalmosaurus, possibly close to
Brachypterygius. Although generally poorly diagnostic, Late Jurassic
Mexican ichthyosaurian remains are relatively abundant; a single
specimen was surely identified as belonging to Ophthalmosaurus. The
new specimen is therefore the first evidence of the presence of a
second ichthyosaurian genus in the Late Jurassic Mexican
Gulf