Dino bites croc and other new papers

[bh480@scn.org]

From: Ben Creisler
bh480@scn.org

A few new papers that might be of interest:

Lucas Ernesto Fiorelli, 2010.
Predation bite-marks on a peirosaurid crocodyliform from 
the Upper Cretaceous of Neuquén Province, Argentina.
Ameghiniana  47(3): 387-400 (2010)

Bite marks and injuries caused by intraspecific predation 
or aggressive social behavior are uncommon in fossil 
vertebrates, and in the fossil record of suchian 
archosaurs they are extremely unusual. A peirosaurid 
crocodyliform collected from the Upper Cretaceous beds of 
the Neuquén Group (northern Patagonia, Argentina) shows 
abundant bite marks and injuries. These injuries are 
spread across all the preserved parts of the specimen, 
with the highest concentration of bite marks, 
perforations and breakage in the caudal region. 
Characteristics of these injuries are analyzed, and their 
possible origin and related taphonomic aspects are 
assessed. Results indicate that the injuries were not 
produced by intraspecific fighting, but probably by the 
predating action of a theropod dinosaur.
http://www.ameghiniana.org.ar/index.php/ameghiniana/articl
e/view/166


 Timothy S. Myers, 2010.
 Earliest Occurrence of the Pteranodontidae (Archosauria: 
Pterosauria) in North America: New Material from the 
Austin Group of Texas.
Journal of Paleontology 84(6): 1071?1081.

Remains of a pteranodontid pterosaur are recorded in the 
basal Austin Group of North Texas. The specimen described 
here comprises a partial left wing and strongly resembles 
Pteranodon although diagnostic features of that genus are 
lacking. With an estimated early Coniacian age, this 
specimen represents the earliest occurrence of the 
Pteranodontidae in North America and the second earliest 
occurrence worldwide, predated only by Ornithostoma from 
the Cambridge Greensand of England. Pterosaur material 
recovered from the Eagle Ford and Austin groups of Texas 
records an early Late Cretaceous change in the 
composition of North American pterosaur communities 
between the late Cenomanian and the early Coniacian. This 
faunal transition appears to be primarily a decrease in 
morphological disparity rather than a significant 
reduction in taxonomic diversity. However, the lack of 
Early Cretaceous Lagerstätten in North America may 
produce underestimates of true pterosaur richness during 
this interval, thereby obscuring a subsequent drop in 
diversity.
http://www.bioone.org/toc/pleo/84/6


Matthew F. Bonnan, Jennifer L. Sandrik, Takahiko 
Nishiwaki, D. Ray Wilhite, Ruth M. Elsey, Christopher 
Vittore (2010)
Calcified cartilage shape in archosaur long bones 
reflects overlying joint shape in stress-bearing 
elements: Implications for nonavian dinosaur locomotion.
Anatomical Record (advance online publication)
Article first published online: 2 NOV 2010
DOI: 10.1002/ar.21266

In nonavian dinosaur long bones, the once-living 
chondroepiphysis (joint surface) overlay a now-fossilized 
calcified cartilage zone. Although the shape of this zone 
is used to infer nonavian dinosaur locomotion, it remains 
unclear how much it reflects chondroepiphysis shape. We 
tested the hypothesis that calcified cartilage shape 
reflects the overlying chondroepiphysis in extant 
archosaurs. Long bones with intact epiphyses from 
American alligators (Alligator mississippiensis), 
helmeted guinea fowl (Numida meleagris), and juvenile 
ostriches (Struthio camelus) were measured and digitized 
for geometric morphometric (GM) analyses before and after 
chondroepiphysis removal. Removal of the chondroepiphysis 
resulted in significant element truncation in all 
examined taxa, but the amount of truncation decreased 
with increasing size. GM analyses revealed that Alligator 
show significant differences between chondroepiphysis 
shape and the calcified cartilage zone in the humerus, 
but display nonsignificant differences in femora of large 
individuals. In Numida, GM analysis shows significant 
shape differences in juvenile humeri, but humeri of 
adults and the femora of all guinea fowl show no 
significant shape difference. The juvenile Struthio 
sample showed significant differences in both long bones, 
which diminish with increasing size, a pattern confirmed 
with magnetic resonance imaging scans in an adult. Our 
data suggest that differences in extant archosaur long 
bone shape are greater in elements not utilized in 
locomotion and related stress-inducing activities. Based 
on our data, we propose tentative ranges of error for 
nonavian dinosaur long bone dimensional measurements. We 
also predict that calcified cartilage shape in adult, 
stress-bearing nonavian dinosaur long bones grossly 
reflects chondroepiphysis shape

http://onlinelibrary.wiley.com/doi/10.1002/ar.21266/abstra
ct