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Olorotitan and Argentine titanosaurs in Acta Palaeontologica Polonica
From: Ben Creisler
bh480@scn.org
New in advance papers for Acta Palaeontologica Polonica:
Pascal Godefroit, Yuri L. Bolotsky, and Ivan Y. Bolotsky
(2011)
Osteology and relationships of Olorotitan arharensis, a
hollowcrested hadrosaurid dinosaur from the latest
Cretaceous of Far Eastern Russia.
Acta Palaeontologica Polonica (advance online publication)
doi:10.4202/app.2011.0051
http://app.pan.pl/article/item/app20110051.html
The holotype of Olorotitan arharensis Godefroit,
Bolotsky, and Alifanov 2003, from the Maastrichtian
Udurchukan Formation in Kundur, Far Eastern Russia, is
the most complete dinosaur discovered in Russia and one
of the best preserved lambeosaurines outside western
North America. This taxon is diagnosed by these
autapomorphies: large helmet-like hollow crest higher
than the rest of the skull and extending caudally well
beyond the level of the occiput; very high postorbital
process of jugal (ratio height of postotbital process /
length of jugal = 1); rostral portion of the jugal
shorter than in other lambeosaurines, with a perfectly
straight rostral margin; very asymmetrical maxilla in
lateral view, with ventral margin distinctly downturned;
very elongated neck composed of 18 cervical vertebrae;
tibia as high as the femur; shorter cnemial crest, about
one fifth of tibia length. A phylogenetic analysis,
based on 118 cranial, dental, and postcranial characters,
indicates that Olorotitan is a member of the
Corythosaurini clade, and is the sister taxon of
Corythosaurus casuarius, Hypacrosaurus stebingeri, and
Hypacrosaurus altispinus. The high diversity and mosaic
distribution of Maastrichtian hadrosaurid faunas in the
Amur ?Heilongjiang region are the result of a complex
palaeogeographical history and imply that many
independent hadrosaurid lineages dispersed readily
between western America and eastern Asia at the end of
the Cretaceous.
***
Rodolfo A. Garcia and Leonardo Salgado (2011)
The titanosaur sauropods from the Allen Formation (late
Campanian-early Maastrichtian) of Salitral Moreno
(Patagonia, Río Negro, Argentina).
Acta Palaeontologica Polonica (advance online publication)
doi:10.4202/app.2011.0055
http://app.pan.pl/article/item/app20110055.html
The dinosaur record of the Salitral Moreno locality (Río
Negro Province, Argentina) is characterized by a high
diversity of herbivore taxa, among them hadrosaurs,
ankylosaurs, and titanosaur sauropods, but carnivores are
rare, consisting of only a few fragmentary bones of small
forms. Titanosaurs are represented by Rocasaurus muniozi
and Aeolosaurus sp., and at least four other taxa,
represented by fragmentary material. The elements
preserved include a cervical, dorsal and caudal
vertebrae, chevron, humerii, ulnae, radii, metacarpal,
femora, tibiae, metatarsal, ischia, pubis and ilium. The
Allen Formation is thought to be correlated with the
Marília Formation in Brazil, and their faunas have
certain elements in common such as aeolosaurines, but
saltasaurines and hadrosaurs, are known exclusively from
the Allen Formation. These absences, and particularly
that of the saltasaurines, may be because those sauropods
originated late in the Cretaceous, probably in southern
South America (Northern Patagonia?), and they did not
have time to disperse to northern South America.