New Cricosaurus (Thalattosuchia) species from Jurassic of Argentina

[Ben Creisler <bcreisler@gmail.com>]

From: Ben Creisler
bcreisler@gmail.com

A new paper:


Yanina Herrera, Zulma Gasparini & Marta S. Fernández (2013)
A new Patagonian species of Cricosaurus (Crocodyliformes,
Thalattosuchia): first evidence of Cricosaurus in Middle–Upper
Tithonian lithographic limestone from Gondwana.
Palaeontology 56 (3): 663–678
DOI: 10.1111/pala.12010
http://onlinelibrary.wiley.com/doi/10.1111/pala.12010/abstract

Upper Jurassic (Tithonian) deposits in north-western Patagonia,
Argentina, have yielded rich and taxonomically diverse assemblages of
marine reptiles. These assemblages are also remarkable by their
quality of preservation and are represented by ichthyosaurs,
plesiosaurs, turtles and crocodyliforms. Despite the abundant
crocodyliform record, only two metriorhynchid taxa have been
identified: Cricosaurus araucanensis and Dakosaurus andiniensis. Here
we described a new species of Cricosaurus, which represents the second
species of Cricosaurus in the Tithonian of the Neuquén Basin, and the
first metriorhynchid found in lithographic limestone from Gondwana.
Furthermore, this specimen has the most complete postcranial remains
of any metriorhynchid from South America. The new species is
characterized by a short distance between the premaxilla and the
nasal, a relatively narrow interorbital width, 23–25 mandibular teeth,
bicarinated teeth with fine apicobasally aligned ridges, interalveolar
spaces between the first seven teeth approximately 1.5 times longer
than the anteroposterior diameter of the respective alveoli. To test
the assignment of the new species to Cricosaurus, we carried out two
phylogenetic analyses. In both analyses, Cricosaurus lithographicus
sp. nov. is nested with other species referred to this genus. This new
species has peculiar enamel ornamentation, characterized by numerous,
fine apicobasally aligned ridges, when compared to other species of
the genus.