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3 T. rexes on display in LA and other new stuff



From: Ben Creisler
bh480@scn.org


3 T. rexes on display in LA
http://www.mercurynews.com/news/ci_17149913?nclick_check=1

E. N. Kurochkin and I. A. Bogdanovich (2010)
Origin of feathered flight. 
Paleontological Journal 44(12):1570-1588.
DOI: 10.1134/S0031030110120129 
http://springerlink.metapress.com/content/n02444p0767n7324/

The origin of flight in birds and theropod dinosaurs is a many-sided and
debatable problem. We develop a new approach to the resolution of this
problem, combining terrestrial and arboreal hypotheses of the origin of
flight. The bipedalism was a key adaptation for the development of flight
in both birds and theropods. The bipedalism dismissed the forelimbs from
the supporting function and promoted transformation into wings. For the
development of true flapping avian flight, a key role was played by the
initial universal anisodactylous foot of birds. This foot pattern provided
a firm support on both land and trees. Theropod dinosaurs, archaeopteryxes,
and some other early feathered creatures had a pamprodactylous foot and,
hence, they developed only gliding descent. Early birds descended by
flattering parachuting with the use of incipient wings; this gave rise to
true flight. Among terrestrial vertebrates, only bats, pterosaurians, and
birds developed true flapping flight, although they followed different
morphofunctional pathways when solving this task. However, it remains
uncertain what initiated the adaptation of the three groups for the air
locomotion. Nevertheless, the past decade has provided unexpectedly
abundant paleontological data, which facilitate the resolution of this
question with reference to birds. 


Pterosaurs 10 Times Heavier than Biggest Birds 
http://news.discovery.com/dinosaurs/pterosaur-weight-footprints-110118.html

The online preprint of this article was mentioned some time back. Here's
the official publication version:

Tai Kubo (2011) 
Estimating body weight from footprints: Application to pterosaurs 
Palaeogeography, Palaeoclimatology, Palaeoecology 299(1-2): 197-199  (1
January 2011)
doi:10.1016/j.palaeo.2010.11.001 
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V6R-51D165W-3&_us
er=10&_coverDate=01%2F01%2F2011&_alid=1615418149&_rdoc=1&_fmt=high&_orig=sea
rch&_origin=search&_zone=rslt_list_item&_cdi=5821&_sort=r&_st=13&_docanchor=
&view=c&_ct=67&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=9d0a
3d9d0324540d89aa8ea87f87b37e&searchtype=a

The body mass of extinct animals have never been estimated from footprints,
despite its potential utility. To redeem this situation, the relationship
between body mass and the areas of footprints was derived from 17 species
of modern tetrapods. Body mass of seven ichnospecies of pterosaur tracks
were estimated, because pterosaur body weight is an intriguing topic with
reference to their flying ability. Estimated body weights of pterosaurs
range from 110 g to 145 kg. The result provides evidence that large
pterosaurs are about 10 times heavier than the heaviest modern bird.


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