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Eodromaeus, new basal theropod from Triassic in Argentina



From: Ben Creisler
bh480@scn.org

For anyone who was holding his/her breath, you can 
breathe again. The paper is officially out, so if someone 
else has not mentioned it yet:

Ricardo N. Martinez, Paul C. Sereno, Oscar A. Alcober, 
Carina E. Colombi, Paul R. Renne, Isabel P. Montañez and 
Brian S. Currie (2011) 
A Basal Dinosaur from the Dawn of the Dinosaur Era in 
Southwestern Pangaea
Science 331 (6014): 206-210 (14 January 2011) 
DOI: 10.1126/science.1198467 
http://www.sciencemag.org/content/331/6014/206.abstract

Abstract
Upper Triassic rocks in northwestern Argentina preserve 
the most complete record of dinosaurs before their rise 
to dominance in the Early Jurassic. Here, we describe a 
previously unidentified basal theropod, reassess its 
contemporary Eoraptor as a basal sauropodomorph, divide 
the faunal record of the Ischigualasto Formation with 
biozones, and bracket the formation with 40Ar/39Ar ages. 
Some 230 million years ago in the Late Triassic (mid 
Carnian), the earliest dinosaurs were the dominant 
terrestrial carnivores and small herbivores in 
southwestern Pangaea. The extinction of nondinosaurian 
herbivores is sequential and is not linked to an increase 
in dinosaurian diversity, which weakens the predominant 
scenario for dinosaurian ascendancy as opportunistic 
replacement. 
  
Also

Michael Balter 
Pint-Sized Predator Rattles The Dinosaur Family Tree
Science 331 (6014): 134 (14 January 2011) 
DOI: 10.1126/science.331.6014.134 
http://www.sciencemag.org/content/331/6014/134.short
Summary
On page 206 of this week's issue of Science, a team 
working in Argentina reports the discovery of a very 
early dinosaur?possibly a distant ancestor of 
Tyrannosaurus rex?that lived about 230 million years ago, 
during what paleontologists call the dawn of the 
dinosaurs. The researchers say the new finds?two 
specimens that together make up a nearly complete 
skeleton of a diminutive, 1-meter-long dinosaur?and 
neighboring fossils show that dinosaurs didn't outcompete 
other reptiles, but rather gradually replaced them as 
their predecessors died out for other reasons. More 
controversially, the team says the fossils show that one 
of the most well-known early dinosaurs, Eoraptor, long 
considered an ancestor of meat eaters like T. rex, was 
actually an ancestor of gigantic plant-eating dinosaurs 
like Apatosaurus. 


There's a cool video also at:

http://news.discovery.com/videos/dinosaurs-dawn-runner-
sheds-light-on-dino-evolution.html