Ancient wildebeest-like animal shared 'bizarre' feature with dinosaur

Date:  February 4, 2016

Source: Cell Press

By poring over the fossilized skulls of ancient wildebeest-like animals (Rusingoryx atopocranion) unearthed on Kenya's Rusinga Island, researchers have discovered that the little-known hoofed mammals had a very unusual, trumpet-like nasal passage similar only to the nasal crests of lambeosaurine hadrosaur dinosaurs. The findings reported in the Cell Press journal Current Biology on February 4 offer "a spectacular example" of convergent evolution between two very distantly related taxa and across tens of millions of years, the researchers say.

"The nasal dome is a completely new structure for mammals-- it doesn't look like anything you could see in an animal that's alive today," says Haley O'Brien of Ohio University, Athens. "The closest example would be hadrosaur dinosaurs with half-circle shaped crests that enclose the nasal passages themselves."

This evolutionary convergence may be explained by similarities in the way Rusingoryx and hadrosaurs lived. In fact, hadrosaurs are sometimes referred to as the "cows of the Cretaceous."

For Tyler Faith of the University of Queensland, one of the study's corresponding authors, it all started in 2009. He and his colleagues were working on a field program in the Lake Victoria region when other scientists directed them to a site they called Bovid Hill. The hill had been so named because of an abundance of fossil Bovidae, the group including antelopes and buffaloes, eroding from its surface.

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