Field museum scientists have discovered a new carnivorous dinosaur that, like T. Rex, had mysterious short forelimbs.
Gualicho shinyae, whose discovery was announced in a paper published Wednesday in the scientific journal PLOS ONE, was first found by the museum’s chief fossil preparator, Akiko Shinya, on a 2007 dig in Patagonia.
A medium-sized predator of the allosaurid branch of theropod dinosaurs, it weighed roughly 1,000 lbs.
Beyond adding a new predator to the mix of animals that have been found in its 90-million-year-old rock unit in northern Patagonia, “this is an animal that evolved these really short, reduced forelimbs that have sort of fascinated paleontologists and laypeople for a long time,” said Pete Makovicky, the Field paleontologist who was on the dig with Shinya and is corresponding author of the paper.
Although the gualicho is not closely related to T. rex, being able to study its similar forelimbs might help solve the mystery of why they evolved.
“It’s something we see in large dominant predators in their ecosystems,” Makovicky said. “They have larger massive skulls used for prey acquisition. The arms are taking not even a secondary role but essentially not being used at all.”