A newly identified dinosaur species with an unusual set of arm muscles fit to lift feathers has helped scientists in Alberta solve a decades-long case of mistaken dinosaur identity.
The bird-like dinosaur, which hunted for food in the bayous and swamps of southern Alberta, was first thought to be part of a different species of dinosaurs.
Now named Apatoraptor pennatus, the dinosaur did not use its arm muscles for lifting heavy weights or brawling, but for moving its feathers, paleontologists from the University of Alberta said.
A Case of Mistaken Identity
Greg Funston, a Ph.D. candidate at the university, was working on a nearly complete fossilized dinosaur skeleton found in the Western Canadian province's badlands when he observed something strange.
Mistakenly thought of as a member of the group of dinosaurs that resemble modern-day ostriches, the fossilized skeleton was classified as an ornithomimid and kept in the Royal Tyrrell Museum since its discovery in 1993. It was brought out again to celebrate the museum's 25th anniversary.
That was when he realized that the skeleton was actually a new type of caenagnathid dinosaur, part of a family of bird-like maniraptoran theropod dinosaurs.
Although the dinosaur was already called Epichirostenotes, Funston said the features did not quite match up. Some of the proportions and several shapes of the finger bones were off, as well as the features of the lower jaw.
After putting the fossils under CT scan, Funston found the signs of unusual arm muscles, which had tiny scars similar to those left by feather-moving muscles of birds.
What were the Feathers For?
The Apatoraptor is about 2 meters (6.6 feet) long and 180 kilograms (396.8 lbs.) in weight, making the dinosaur a bit larger than the average human.
"Because these animals are way too big to fly, they're probably using their feathers for display," said Funston, adding that the displays were possibly meant to attract potential mates.
Implications of the Discovery
The name Apatoraptor means "deceptive thief" while pennatus means "feathered," Funston said. This is his first time naming a new dinosaur.
"It's really exciting on a personal level," said Funston. "But what I am most excited about is what it means for this field of paleontology."
The Apatoraptor fossil is the most articulated skeleton from anywhere in the world. This means that the dinosaur's bones are still in the same position when it died. It's also by far the most complete skeleton for caenagnathids in Alberta.
The discovery of the well-preserved fossilized skeleton is very crucial as it will help future studies further understand the new dinosaur species. Funston said it will help fill in the gap for some of the missing puzzle pieces in the group of caenagnathids.
"Because it is a relatively complete skeleton, it helps resolve the relationships of caenagnathids, which have always been problematic," said Funston.
In fact, most caenagnathid fossils are only represented by single bones or isolated material. With this, scientists couldn't tell if they came from the same dinosaur.
Apatoraptor helps scientists picture what these animals looked like, allowing them to confirm if the features they use to separate the caenagnathids are significant or not.
The findings of the study are published in the Journal of Vertebrate Paleontology.
