Romeosaurus, new mosasaur from Italy

[Ben Creisler <bcreisler@gmail.com>]

From: Ben Creisler
bcreisler@gmail.com


A new paper in JVP:


Alessandro Palci, Michael W. Caldwell & Cesare A. Papazzoni (2013)
A new genus and subfamily of mosasaurs from the Upper Cretaceous of
northern Italy.
Journal of Vertebrate Paleontology 33(3): 599-612
DOI:10.1080/02724634.2013.731024
http://www.tandfonline.com/doi/full/10.1080/02724634.2013.731024#.UYm7FLXvtcQ

A new genus and two new species of mosasaurs are described from five
specimens collected during quarrying operations in the ‘Lastame’
lithotype located in the mountains of northern Italy just to the north
of Verona (lower Turonian–lower Santonian). These mosasaurs share some
anatomical characters with the North American taxon Russellosaurus
coheni, but the presence of distinctive features suggests placement
into two new species within a new genus (e.g., forked distal tip of
suprastapedial process of quadrate; suture between maxilla and
premaxilla extends to point above third tooth position [cf. second in
Russellosaurus]). We conducted two phylogenetic analyses of the
Mosasauroidea (37 ingroup taxa, 131 characters), the first one with
equally weighted characters and the second after successive weighting
in order to reduce homoplastic noise and amplify the signal in the
data. The first analysis (equal weights) resulted in 96 most
parsimonious trees, whereas the second produced a single shortest
tree. Both analyses consistently placed the new genus as the sister
taxon to Russellosaurus, and these two taxa were placed together with
Yaguarasaurus, in a clade that is the sister group of the
Tethysaurinae (Tethysaurus and Pannoniasaurus). A new clade of
mosasaurs, the Yaguarasaurinae, is here defined as comprising the most
recent common ancestor of Russellosaurus, Romeosaurus, and
Yaguarasaurus, and all of its descendants.