News blog

Tiny T Rex ancestor still pretty scary

raptorexT. Rex’s notoriously massive head, sharp teeth and piddly diddly arms first evolved in a runty ancestor one hundredth its size, paleontologists reported in Science yesterday. The nine-foot-long Raptorex kriegsteini lived about 35 million years before its multi-ton descendant, but already bore many of its hallmark features.

The findings come as a surprise for paleontologists, who thought these features evolved as the tyrannosaurids grew to become the colossal beasts we see in the movies — the limbs withering as the head and body expanded. Raptorex throws this idea a pretty nasty curve ball, suggesting that the same body plan could have withstood two orders of magnitude of growth.

The Chicago Tribune give some juicy details of the fossil’s shady legal history: The specimen was smuggled out of a fossil field in Inner Mongolia, an autonomous region in northern China, then carted off to an “illegal international black market for fossils.” A Massachusetts eye surgeon and amateur paleontologist named Henry Kriegstein (hence the fossil’s name) later purchased it (legally) for “tens of thousands of dollars, but well below $100,000”, he told the Tribune.


Eventually Kriegstein realized the 125 million-year-old bones, then encased in a stone block, might be of some value to the scientific community, so he handed it over to paleontology superstar Paul Sereno at the University of Chicago, who declares, “this animal really changes the way we look at all tyrannosaur evolution”. The fossil will eventually return to Inner Mongolia.

The Washington Post points out some caveats to the study, including the fossil’s questionable location of origin and Sereno’s assertion, based on certain fused bones, that the raptorex was almost fully grown.

More Coverage

Fossil Find Challenges Theories on T. Rex – New York Times

Tiny T. rex fossil discovery startles scientists – CNN

Study finds T. rex had 8-foot mini precursor – USA Today

Photo: Todd Marshall/Science

Comments

Comments are closed.