Scientists say that the fossil of a close relative of Tyrannosaur rex bolsters their case for a distinctive southern population of the fearsome dinosaurs.
The pile of crumbling dinosaur bones languished in a drawer at the Museo del Desierto in Saltillo, Mexico, for two decades.
“When you see that thing sitting in a museum drawer, it looks pretty underwhelming,” said Nick Longrich, a paleontologist from the University of Bath in England. “It looks like a pile of rubble.”
But the dire condition of the bones, discovered in 2000 in the Chihuahuan desert in northern Mexico, concealed a secret: They belonged to a close relative of Tyrannosaurs rex. Unlike its heavily built cousin, this animal was long-legged and lightly built, with big eyes that may have helped it hunt in low light and a heavy snout for dispatching helpless prey.
It is only the second tyrannosaur species ever found in Mexico. The species has been named Labocania aguillonae after Martha Carolina Aguillón, the local paleontologist who discovered it. Dr. Longrich and Héctor Rivera-Sylva of the Museo del Desierto described the species Wednesday in the journal MDPI Fossil Studies, calling it a key piece of evidence of a southern tribe of tyrannosaurs that were distinct from northern specimens.
Seventy to 80 million years ago, North America’s west was home to multiple tyrannosaur species. Most of them — animals like Albertosaurus, Daspletosaurus and the eventual emperor of the continent, Tyrannosaurus rex — are known from specimens found in the Great Plains or Canada.
Over the last two decades, however, a handful of tyrannosaur species have been discovered in Utah and New Mexico, Dr. Longrich said.