Scientists may now be able to better understand how horned dinosaurs evolved thanks to a 79 million-year-old fossil.
Strange name belies important discovery
Wendiceratops pinhornensis may sound like a strange name for a dinosaur, but it is actually perfectly logical. The fossilized bones were found in Canada’s Pinhorn Provincial Grazing Reserve by fossil hunter Wendy Sloboda in 2010.
A dig at the site uncovered over 200 bones, which allowed paleontologists to construct a picture of a horned dinosaur which measured 6-meters in length and weighed over a ton. As well as a pair of horns on its brow, Wendiceratops boasted another horn on its nose, and a strange frill with hornlets that grew in on themselves like hooks.
These characteristics had not been seen in other species which were alive during that time in modern day Canada. Michael Ryan, a paleontologist at the Cleveland Museum of Natural History, says that the combination provides evidence of a great deal of diversity among horned dinosaurs.
Skull ornamentation varies greatly among horned dinosaurs, and it is thought that their evolution was influenced greatly by the way they used their heads. “That’s where all the evolution is happening in these animals,” Ryan said.
Paper sets out evolution of horned dinosaurs
A paper by Ryan, along with co-author David Evans of the Royal Ontario Museum, outlines the ramifications of the find. The full version was published Wednesday by open-access journal PLOS ONE.
According to the paper, Wendiceratops was one of the first dinosaurs in its evolutionary line to feature a large horn on its nose. This would indicate that nasal horns developed for different reasons in two branches of the dinosaur evolutionary tree. Wendiceratops is part of one branch, while another branch features perhaps the most famous horned dinosaur, Triceratops.
The scientists also noticed similarities between the hornlets on Wendiceratops’ fringe and the ornaments found on Sinoceratops, a Chinese horned dinosaur which roamed the Earth around 72 million years ago. Ryan believes that this supports the theory that Wendiceratops’ descendants may have moved from the Americas to Asia.
He also claims that the shapes of the skulls of horned dinosaurs may be related to sexual signaling and head-butting competitions that males of the species participated in, which can be compared to behavior exhibited by Bighorn sheep.
Pace of evolution increased by climate change
Horned dinosaurs evolved more quickly than other species during the Cretaceous Period. Ryan states that vertebrate species more commonly appeared and went extinct within 2 million to 4 million years, but horned dinosaurs did so much more quickly. “We’re finding that these horned dinosaurs replaced each other every half-million years,” he said.
One possible explanation for the rapid evolution of horned dinosaurs may be the rapid pace of environmental change in North America at the time. The Cretaceous Period was marked by warmer temperatures and rising water levels in the Western Interior Seaway, and Wendiceratops could have evolved faster as a result of environmental changes.
“Maybe the rapid evolution we’re looking at is related to climate change,” Ryan said. Could the pace of evolution be increasing in the modern world due to global warming? The Wendiceratops fills in some gaps in our previous knowledge of the evolutionary history of the dinosaurs, and raises some interesting questions about future evolutionary patterns.