Cricosaurus (Thalattosuchia) postcranial skeleton from Jurassic of Argentina

[Ben Creisler <bcreisler@gmail.com>]

From: Ben Creisler
bcreisler@gmail.com

A new online paper:

Yanina Herrera, Marta S. Fernández & Zulma Gasparini (2013)
Postcranial skeleton of Cricosaurus araucanensis (Crocodyliformes:
Thalattosuchia): morphology and palaeobiological insights.
Alcheringa 37 (advance online publication) 1–14
DOI: 10.1080/03115518.2013.743709
http://www.tandfonline.com/doi/full/10.1080/03115518.2013.743709#.UZkLobW1FcQ


The metriorhynchid crocodyliform Cricosaurus araucanensis (Gasparini &
Dellapé) has been documented from Tithonian (Upper Jurassic) strata of
the Vaca Muerta Formation exposed in the Neuquén Basin, northwest
Patagonia, Argentina. Postcranial components of this species were
mentioned but not described in the original analysis. Subsequently,
other authors described the forelimbs. The postcranial elements of
metriorhynchids are poorly documented in comparison with their skulls,
but new data from C. araucanensis reveal delayed ossification of the
caudal neurocentral sutures indicating skeletal paedomorphosis
affecting not only the appendicular skeleton but also the posterior
region of the vertebral column. The morphology of the caudal region
(transverse processes of the first caudal vertebrae ventrally
deflected) and the reduction in the femur of the fourth trochanter
suggest a reduction of the hypaxial musculature allowing increased
epaxial musculature. This pattern of musculoskeletal arrangement is
consistent with the swimming style and propulsion by lateral
undulation of the tail, as proposed by previous authors.