Diegocanis, new eucynodont from Triassic Ischigualasto Formation, Argentina (free pdf)

[Ben Creisler <bcreisler@gmail.com>]

From: Ben Creisler
bcreisler@gmail.com


A new paper in open access:

Ricardo N. Martínez, Eliana Fernandez & Oscar A. Alcober (2013)
A new non-mammaliaform eucynodont from the Carnian-Norian
Ischigualasto Formation, Northwestern Argentina.
REVISTA BRASILEIRA DE PALEONTOLOGIA 16 (1): 147-156
doi:10.4072/rbp.2013.1.05
http://www.sbpbrasil.org/revista/edicoes/16_1/05_Martinez_et_al.pdf


The record of non-mammaliaformes eucynodonts from the Carnian-Norian
Ischigualasto Formation is diverse and abundant, including a medium to
large size herbivore and small carnivores. Here is described a new
small eucynodont from the Ischigualasto Formation, on the basis of a
partial skull. The new taxon is characterized by palatal process of
the premaxilla extending posterior to the level of the fi rst
postcanine; deep and large maxillary laterodorsal fossa that opens at
the level of the root of the upper canine; and postorbital bar
diverging posterolaterally at very low angle (35.6°) from the
anteroposterior axis of the skull. Results from a phylogenetic
analysis supports the new genus placement as a probainognathian
eucynodont, more derived than Probainognathus Romer, and more closely
related to Ecteninion Martinez, May & Forster and Trucidocynodon
Oliveira, Soares & Schultz than to any other eucynodont. Ecteniniidae
is proposed as a new clade including the new genus, Ecteninion and
Trucidocynodon, and in the phylogenetic hypothesis represents the
sister-group of Prozostrodontia (Prozostrodon Bonaparte & Barberena,
Tritylodontidae and Mammaliaformes). Additionally, the new taxon from
the Ischigualasto Formation shows that the
Scaphonyx-Exaeretodon-Herrerasaurus biozone has similar cynodont
diversity than the supposedly contemporaneous Hyperodapedon Assemblage
Zone of Santa Maria 2 Sequence, in Southern Brazil.