Mendozasaurus and Zupaysaurus papers

["bh480@scn.org" <bh480@scn.org>]

dinosaur@usc.edu
From: Ben Creisler bh480@scn.org
In case these have not been mentioned yet, the new issue of Ameghiniana
describes two new dinosaurs:

GONZÁLEZ RIGA, Bernardo J., 2003. A new titanosaur (Dinosauria, Sauropoda)
from the Upper Cretaceous of Mendoza Province, Argentina.
Ameghiniana 40(2): 155 - 172. 
Abstract. MENDOZASAURUS NEGUYELAP GEN. ET SP. NOV. IS A NEW TITANOSAUR FROM
THE UPPER CRETACEOUS OF NEUQUÉN BASIN AND THE FIRST KNOWN DINOSAUR SPECIES
FROM MENDOZA PROVINCE, ARGENTINA. The remains were found in levels
provisionally referred to the Río Neuquén Formation (late Turonian-late
Coniacian) of the Neuquén Group. They consist of 22 mostly articulated
caudal vertebrae, a dorsal vertebra, numerous disarticulated appendicular
bones and osteoderms. Autapomorphies of Mendozasaurus are: (1)
subtriangular infrapostzygapophyseal fossae in anterior dorsal vertebrae;
(2) postzygapostspinal laminae parallel to the plane of the
postzygapophyseal facets in anterior dorsal vertebrae; (3)
interzygapophyseal cavity dorsoventrally extended and limited by the
spinopostzygapophyseal and spinoprezygapophyseal laminae in anterior caudal
vertebrae; (4) middle caudal vertebrae slightly procoelous with reduced
posterior condyles displaced dorsally; (5) laminar mid-posterior caudal
neural spines with horizontal and straight dorsal border, and anterodorsal
corner forming a right angle; (6) large subconic-spherical osteoderms
lacking cingulum. A cladistic analysis permits the inclusion of
Mendozasaurus within Titanosauridae, according to the phylogenetic
definition of this clade. Although this new species exhibits almost all the
titanosaurid synapomorphies proposed by some authors, it lacks prominent
posterior condyles in middle caudal centra. This and other plesiomorphic
traits suggest that Mendozasaurus is a basal titanosaurid, more derived
than Malawisaurus in the caudal procoely. 

ARCUCCI, Andrea B & Rodolfo A. CORIA, 2003. A new Triassic carnivorous
dinosaur from Argentina. Ameghiniana 40(2): 217 - 228. 
Abstract. A new Triassic theropod, Zupaysaurus rougieri is described from
La Rioja Province and its phylogenetic relationships amongst Theropoda are
discussed. Zupaysaurus shares with Tetanurae several features that include
the presence of a tooth row that is anterior to the orbit, a pneumatized
lacrimal, and a tibia with a posterolaterally concave and transversely
expanded distal end. Features shared with some ceratosaurs, like the
presence of a longitudinal alveolar ridge on the maxilla, a large
antorbital fenestra, and a fused astragalus-calcaneum, are either
homoplasies with some ceratosaurs or plesiomorphic features within
Neotheropoda. Based on relative stratigraphical position, Zupaysaurus is
regarded as Late Triassic in age, which makes it the oldest record of
Tetanurae. Zupaysaurus provides data about the early evolution of
theropods, strengthening the assumption about the origin of tetanurans in
the Late Triassic, and indicating their simultaneous record with the oldest
coelophysids (i.e. Coelophysis and Liliensternus).


--------------------------------------------------------------------
mail2web - Check your email from the web at
http://mail2web.com/ .