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Mapusaurus roseae & Antarctopelta oliveroi


Coria R. A. & Currie P. J. 2006. ? A new carcharodontosaurid (Dinosauria, 
Theropoda) from the
Upper Cretaceous of Argentina. Geodiversitas 28 (1) : 71-118.
A new carcharodontosaurid theropod from the Huincul Formation (Aptian-
Cenomanian, Upper Cretaceous) of Neuquén Province, Argentina, is described.
Approximately the same size as Giganotosaurus carolinii Coria & Salgado, 1995,
Mapusaurus roseae n. gen., n. sp. is characterized by many features including a
deep, short and narrow skull with relatively large triangular antorbital fossae,
relatively small maxillary fenestra, and narrow, unfused rugose nasals. 
roseae n. gen., n. sp. has cervical neural spines and distally tapering 
tall dorsal neural spines, central pleurocoels as far back as the first sacral
vertebra, accessory caudal neural spines, stout humerus with poorly defined
distal condyles, fused metacarpals, ilium with brevis fossa extending deeply 
ischial peduncle, and femur with low fourth trochanter. Phylogenetic analysis
indicates that Mapusaurus n. gen. shares with Carcharodontosaurus Stromer,
1931 and Giganotosaurus Coria & Salgado, 1995 several derived features that
include narrow blade-like teeth with wrinkled enamel, heavily sculptured facial
bones, supraorbital shelf formed by a postorbital/palpebral complex, and
a dorsomedially directed femoral head. Remains of Mapusaurus n. gen. were
recovered from a bonebed where 100% of the identifiable dinosaur bones can
be assigned to this new genus. Based on the metatarsals recovered, a minimum
of seven individuals was buried at the site. It is conceivable that this bonebed
represents a long term or coincidental accumulation of carcasses. The presence
of a single carnivorous taxon with individuals of different ontogenic stages 
evidence of variation within a single population, and may also indicate
some behavioural traits for Mapusaurus roseae n. gen., n. sp.

Antarctopelta is the 2nd named dinosaur from Antarctica.

Salgado L. & Gasparini Z. 2006. ? Reappraisal of an ankylosaurian dinosaur from 
the Upper
Cretaceous of James Ross Island (Antarctica). Geodiversitas 28 (1) : 119-135.
The holotype of the upper Campanian ankylosaur Antarctopelta oliveroi n. gen.,
n. sp., from James Ross Island, Antarctica, is described. Diagnostic characters
include short cervicals (centrum length about 70% of the centrum height),
distal caudal vertebrae with transverse processes well developed (centrum width
including the transverse processes exceeds 30% of the posterior articulation
width) and dorsoventrally depressed, and the presence of smooth, sub-circular
osteoderms, surrounded by a mosaic of smaller polygonal osteoderms with a
rugose surface texture and tiny, button-like ossicles. While a number of 
such as relatively large teeth with respect to the mandible and the presence of 
asymmetrical cingulum, suggest an affinity with the Nodosauridae, others such
as the dorsoventrally depressed morphology of the distal caudal vertebrae and,
especially, the presence of ossified tendons on their ventral side, 
characterize the
Ankylosauridae. This uncertainty impedes evaluation of the paleobiogeographical
significance of this new species of dinosaur.

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