Xenotarsosaurus (Greek for "strange tarsus lizard"); pronounced ZEE-no-TAR-so-SORE-us
Woodlands of South America
Late Cretaceous (70-65 million years ago)
Size and Weight:
About 20 feet long and one ton
Bipedal posture; short arms
Paleontologists aren't quite sure what to make of Xenotarsosaurus, beyond the fact that it was a large theropod dinosaur of late Cretaceous South America. Tentatively, this meat eater has been classified as an abelisaur, and its stunted arms bear some resemblance to those of the much better-known Carnotaurus. However, there's also a case to be made that Xenotarsosaurus was an allosaur rather than an abelisaur, and thus more closely related to the North American Allosaurus (which lived tens of millions of years earlier). Whatever the case, associated fossil remains imply that Xenotarsosaurus preyed on Secernosaurus, the first hadrosaur ever to be identified in South America.