A wildebeest-like animal that lived in Kenya some 75,000 years ago had one surprising similarity with dinosaurs that lived millions of years earlier. Rusingoryx atopocranion, described in a paper published Thursday in Current Biology, seems to have had the honker of a hadrosaur.
"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," study author Haley O'Brien of Ohio University said in a statement. "The closest example would be hadrosaur dinosaurs with half-circle shaped crests that enclose the nasal passages themselves."
The researchers instantly noticed a superficial similarity between crescent-shaped protrusions seen on the newly found skulls and those seen on duck-billed dinosaurs. But they were shocked when they found that the internal bone structure was hollow — just like a hadrosaur's.
Rusingoryx atopocranion, a mammal, certainly isn't related to any dinosaurs (at least not more than the average vertebrate, anyway). This isn't a nasal shape that evolved in hadrosaurs and then meandered its way down the family line until reaching a wildebeest in Kenya. Instead, this is a case of convergent evolution: a feature that independently evolved more than once in the animal kingdom.
If a hoofed animal was going to wind up being similar to any dinosaur, it figures it would be a hadrosaur: The duck-billed beasts are sometimes called the "cows of the Cretaceous," because their 1400-or-so flat, horse-like teeth — which they shed and replaced constantly, shark-style — made them the premier grazers of their day.
It's possible that the hollow nasal crests evolved in both duck-billed dinosaurs and wildebeest types because of lifestyle similarities. The hollow structure of the crest would have allowed both kinds of creatures to deepen their vocal calls, perhaps even producing sounds that only members of their own species could hear. For social herbivores that spread out to graze, these vocalizations would be invaluable in keeping the herd together and safe from predators — be they human or T. rex.