Thursday, June 28, 2012

Bicentenaria argentina, a new theropod dinosaur from Argentina

Bicentenaria argentina, a new theropod dinosaur from Argentina

Argentina has commemorated the 200th anniversary of its May revolution that led to the country independence on May 25, 2010. Two years later, paleontologists from that country announced the discovery of a new dinosaur and named it after the event, perhaps because the remains were unearthed on that day.  Bicentenaria argentina was unveiled to the public on Tuesday June 26, 2012 through a short press release  with pictures of the mounted skeletons of two fighting individuals (from which my illustration is based on). It is a small theropod that measured about 2.5 meters in length. The paragraph quoted from an interview with lead paleontologist Fernando Novas simply says that Bicentenaria is part of a group of dinosaurs that contain tyrannosaurs and Velociraptor and a distant ancestor to birds. This hints that Bicentenaria is a coelurosaur. The pictures of the mounted skeletons do not tell how much of it is actually known, as people tend nowadays to reconstruct entire skeletons from rather incomplete material. The actual remains consist of some 130 bones from at least 3 adults and several juveniles. The mounts look like those of a generic small size theropod, which probably means that Bicentenaria was a rather basal coelurosaurian, neither a tyrannosauroid, nor a dromaeosaur. However, the press release says the fossil is 90 million year old, thus Late Cretaceous, which seems a bit of a young age for a basal coelurosaur. I could guess the remains were found in the Portezuelo Formation of Turonian age in the Rio Negro Province, which means that Bicentenaria was a contemporary of the fabled Megaraptor, the dromaeosaurs Neuquenraptor and Unenlagia, as well as the alverezsaur Patagonykus. But let’s wait for the formal  publication of the description of this intriguing animal.

Correction: I was just told that Bicentenaria is from the Candeleros Formation of Cenomanian age, therefore a contemporary of Giganotosaurus and Buitreraptor.
 
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