Dinosaur-like nostrils found in ancient wildebeest creature

While analyzing the fossilized skulls of an ancient wildebeest-like creature originally discovered on Rusinga Island in Kenya, researchers made a starting discovery: the extinct animal had an odd trumpet-like nasal passage similar to those of a Cretaceous period dinosaur.

The creature is question, Rusingoryx atopocranion, is a hoofed mammal that was first found at a site called Bovid Hill in the Lake Victoria region of the island, co-lead author Haley O’Brien of Ohio University and her colleagues explained earlier this week in a press release.

The similarities between its nasal features and those of lambeosaurine hadrosaur dinosaurs were said to be remarkable, despite the fact that the two species are only very distantly related and are separated by tens of millions of years, the authors said. Their findings are detailed in a new study published in the latest edition of the journal Current Biology.

“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,” said O’Brien, who is a biological scientist specializing in ecology and evolutionary biology at OU. “The closest example would be hadrosaur dinosaurs with half-circle shaped crests that enclose the nasal passages themselves.”

“The thing that’s really remarkable is that lambeosaurine hadrosaurs are the only other animals that we know of that have a similar feature,” added Dr. Daniel Peppe, an associate professor of geosciences in Baylor’s College of Arts and Sciences and co-director of the project.

Similar upbringings may explain the convergent evolution

Dr. Peppe called the discovery “a fantastic example of convergent evolution,” a phenomenon which occurs when two different creatures wind up evolving the same features independently. Rusingoryx atopocranion, a bovid, is clearly not closely related to a dinosaur, he said, but the two different species may be similar in how they lived their lives.

Both types of animals may have developed in the same way as they grew from juveniles into adults, the researchers explained. Both are believed to have been herbivores that lived in large herds in relatively open environments, and both would likely have been exposed to much the same kind of environmental pressures that would have encouraged the development of a nasal crest that allowed for vocalizations.

The findings indicate that the Rusingoryx atopocranion probably used its unusual nasal passage for communications. The trumpet-like feature would have caused the bovid to sound similar to a vuvuzela, and would have allowed it to deepen its normal vocal calls. The research even suggests that the creatures might have been able to make calls at near-infrasound levels to prevent other kinds of animals from hearing the herd communicating with one another.

“Vocalizations can alert predators, and moving their calls into a new frequency could have made communication safer,” said O’Brien. “On top of this, we know that [both] Rusingoryx and hadrosaurs were consummate herbivores, each having their own highly specialized teeth. Their respective, remarkable dental specializations may have initiated changes in the lower jaw and cheek bones that ultimately led to the type of modification we see.”


Image credit: Todd S. Marshall