Ancient wildebeest cousin boasted bizarre dinosaur-like trait

Thu Feb 4, 2016 3:14pm EST
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By Will Dunham

WASHINGTON (Reuters) - In an ancient streambed on Kenya's Rusinga Island, scientists have unearthed fossils of a wildebeest-like creature named Rusingoryx that boasted a weird nasal structure more befitting of a dinosaur than a mammal.

Researchers said on Thursday the crescent-shaped protrusion atop the head of Rusingoryx, which roamed Africa's savannas tens of thousands of years ago, was unlike anything on any other mammal, past or present. Instead, it resembled the head crests of a group of duckbilled dinosaurs called hadrosaurs.

The hollow structure may have enabled the horned, hoofed grass-eater to produce a low trumpeting sound to communicate over long distances with others in its herd, Ohio University paleontologist Haley O'Brien said.

"This structure was incredibly surprising," O'Brien said. "To see a hollow nasal crest outside of dinosaurs and in a mammal that lived so recently is very bizarre."

The fossils of Rusingoryx, about the size of its close cousin the wildebeest, date from about 55,000 to 75,000 years ago. Hadrosaurs with similar nasal structures, Lambeosaurus and Corythosaurus, lived about 75 million years ago.

O'Brien said the structure was an example of "convergent evolution" in which disparate organisms independently evolve similar features, like the wings of birds, bats and the extinct flying reptiles called pterosaurs, to adapt to similar environments or ecological niches.

Rusingoryx led a lifestyle similar to hadrosaurs: herbivores both likely traveling in herds. Many scientists think hadrosaurs also used their crests to communicate vocally with one another.

The researchers said Rusingoryx's nasal apparatus may have allowed it to deepen its normal vocal calls into "infrasound" levels other species may not have been able to hear.   Continued...

An artist's interpretation of Rusingoryx atopocranion on the Late Pleistocene plains of what is now Rusinga Island, Lake Victoria is seen in an undated illustration courtesy of Todd S. Marshall. Scientists said on February 4, 2016, that fossils unearthed in Kenya showed that a horned, hoofed grass-eater called Rusingoryx that roamed Africa's savannas tens of thousands of years ago boasted an odd nasal structure unlike any other mammal, past or present.  REUTERS/Todd S. Marshall/Handout via Reuters