Alnashetri, new coelurosaurian theropod from Late Cretaceous of Argentina

[Ben Creisler <bcreisler@gmail.com>]

From: Ben Creisler
bcreisler@gmail.com

A new online paper:


Peter J. Makovicky, Sebastián Apesteguía, and Federico A. Gianechini (2012)
A New Coelurosaurian Theropod from the La Buitrera Fossil Locality of
Río Negro, Argentina.
Fieldiana Life and Earth Sciences Number 5 :90-98
doi: http://dx.doi.org/10.3158/2158-5520-5.1.90
http://www.bioone.org/doi/abs/10.3158/2158-5520-5.1.90


A new coelurosaurian theropod, Alnashetri cerropoliciensis, is
reported here based on articulated hind limbs of a single individual
discovered at the locality of La Buitrera (Candeleros Formation,
Cenomanian–Turonian), Río Negro Province, Argentina. The new taxon
differs from other coelurosaurs in the possession of a low ridge that
separates the rostral tibial surface from the outer face of the
lateral malleolus, and which extends proximally beyond the tip of the
ascending process of the astragalus, and in the possession of ventral
notches on the hemicondyles of the distal articulations on pedal
phalanges III-1 and III-2. Alnashetri is easily distinguished from the
dromaeosaurid Buitreraptor, the only other known small theropod from
La Buitrera. Phylogenetic analysis supports alvarezsauroid affinities.
The evidence supporting this relationship comes from the detailed
anatomy of the ankle, however, and this concentration of character
support within a single anatomical region may bias our results. If our
proposed phylogenetic placement is accurate, Alnashetri antedates all
other Argentinian alvarezsaurids and indicates that alvarezsaurids
were present in the Neuquén Basin throughout the entire Late
Cretaceous.