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Olorotitan and Argentine titanosaurs in Acta Palaeontologica Polonica

From: Ben Creisler

New in advance papers for Acta Palaeontologica Polonica:
Pascal Godefroit, Yuri L. Bolotsky, and Ivan Y. Bolotsky 
Osteology and relationships of Olorotitan arharensis, a 
hollowcrested hadrosaurid dinosaur from the latest 
Cretaceous of Far Eastern Russia.
Acta Palaeontologica Polonica (advance online publication)

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)

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.