An ancient wildebeest-like creature shared remarkably similar features with “duck-billed” dinosaurs, a new study of skulls suggests.
The bones of several Rusingoryx atopocranion, a sociable and resilient beast that roamed during the Late Pleistocene, were uncovered at a particularly crowded site in Kenya’s Rusinga Island, on Lake Victoria.
Researchers were puzzled by the large collection of animals buried together, and experts say the presence of hand tools and spears may even point to the involvement of early humans in the mass grave.
However, the most interesting revelation came more recently, when a team of scientists analysed the a number of skulls of this enigmatic hoofed mammal, uncovering a nasal passage and jaw unlike any animal alive in the world today.
“I was astonished to see that the skulls looked unlike any antelope that I had ever seen,” says Tyler Faith, an archaeologist at the University of Queensland and corresponding author of the paper.
“The only thing more surprising would have been fossil zebras with horns growing from their heads!”
The CT scans revealed a hollow nasal dome in the skull of Rusingoryx. This feature is similar to the semi-circle crests that enclose the nasal passages of hadrosaurs – herbivores of the Upper Cretaceous period that once roamed what is now Asia, Europe and North America.
Researcher Haley O’Brien of Ohio University in Athens says the find was quite a surprise.
“We were expecting the inside of the dome to have something closer to normal mammalian anatomy, but once we took a look at the CT scans, we were pretty shocked.”
Researchers have drawn comparisons between the lives of Rusingoryx and the hadrosaurid family, including their social behaviours, which may have required unique forms of communication.
O’Brien says the anatomical similarities may have allowed these species to omit very deep vocalisations, which could be used to alert against predators, or to keep communication safe.
“On top of this, we know that both Rusingoryx and hadrosaurs were consummate herbivores, each having their own highly specialised teeth. Their respective, remarkable dental specialisations may have initiated changes in the lower jaw and cheekbones that ultimately led to the type of modification we see in the derived, crest-bearing forms.”
Researchers say these comparisons reflect a convergent evolution, apparent in two species with only a very distant relationship, and divided by tens of millions of years.