Faint striations in the fossils of two small recent dinosaur discoveries in the Drumheller valley is making the science community buzz this week.
On October 26, the American Association for the Advancement of Science published the findings of Royal Tyrrell Museum Palaeontologist Francois Therrien and fellow University of Calgary researcher Darla Zelisnky.
They have discovered the first feathered dinosaurs on the continent of North America.
“Since 1998 we have been discovering dinosaurs with feathers, so that’s no surprise, now we have good understanding of how feathers evolved from meat eating dinosaurs, leading up to birds,” he explains. “Ornithomimids were a mystery, there was a gap in our understanding. Even though good specimens had been discovered in Alberta for over 100 years, none of them had ever been found with feathers.”
Two fossils of the aptly named Ornithomimids (Greek for “bird-mimic lizards”) were recently uncovered in the valley; one in 2009 near the Drumheller landfill, and one in 2008 near Kirkpatrick.
This is not only the first time a feathered Dinosaur has been found on the continent, but the first Ornithomimid with feathers.
The discovery of a juvenile specimen shows remnants of a down-like plumage, while the adult dinosaur discovered shows full large feathers and wing structures. The scientists revisited an older specimen in the museum’s collection to confirm their findings.
In some of the fossils the feathers show up as striations, while in others there are dark carbon streaks. The distribution of the markings matched the pattern on modern wings.
Therrien said the downy feathers were of an insulating nature, and the plumage and developed feathers on the more mature fossil could have served for reproductive purposes.”
“Before, we thought, the wings would have been for flight or gliding, or help the animal escape predators, but now we find wings in adults and not babies. We looked at other birds and mammals, but also at dinosaurs… all those crests and horns and ornamentation only occur with sexual maturity,” said Therrien.
“Young guys don’t need this but when they get in to the game for sexual reproduction to try to display for courtship to impress female and scare away competing males, we think this is when these structures become important.”
Therrien explained, like most discoveries, it was sort of an accident. Because of the coarse sandstone in the area scientists simply felt feathers would be a long shot to find.
When they were unearthing one of the finds he joked with technicians, “If we were in China, we would call these feathers,” referring to the fine details often preserved in Chinese fossils, including feathered dinosaurs.
For so many years people haven’t been paying attention to specimen in sandstone because they suspected feathered dinosaurs would only be preserved in fine grain rocks,” he said.
He said this is the discovery highlight the leading professional work being done at the Tyrrell Museum.
“After 100 year of collecting in the valley, there is still lots to learn and discover right here,” he said.
Another advantage for the museum is discoveries like this can be shared with the public right away. Rather than locking finds in a drawer, they hope to have them available for public consumption next month.
François Therrien shows a Ornithomimid discovered in the Drumheller valley. It it the first dinosaur with feathers found in North America.
inSide photo by Patrick Kolafa