Washington, July 11 (ANI): A team of paleontologists has found evidence of dinosaur burrows in Victoria, Australia, which would help shed light on long-term geologic change, and how organisms may have adapted as the Earth has undergone periods of global cooling and warming.
The find, by paleontologist Anthony Martin and his team from Emory University, US, suggests that burrowing behaviors were shared by dinosaurs of different species, in different hemispheres, and spanned millions of years during the Cretaceous Period, when some dinosaurs lived in polar environments.
In 2006, in collaboration with colleagues from Montana State University and Japan, Martin identified the 95-million-year-old skeletal remains of a small adult dinosaur and two juveniles in a fossilized burrow in southwestern Montana.
They later named the dinosaur species Oryctodromeus cubicularis, meaning, "digging runner of the lair."
The researchers hypothesized that, besides caring for young in their dens, burrowing may have allowed some dinosaurs to survive extreme environments - throwing a wrench in some extinction theories.
A year after the Montana find, Martin traveled to the Victoria coast, which marks the seam where Australia once snuggled against Antarctica.
During a hike to a remote site known as Knowledge Creek, west of Melbourne, Martin rounded the corner of an outcropping and was astounded to see, right at eye level, the trace fossil of what appeared to be a burrow almost identical to the one he had identified in Montana.
The probable burrow etched into the Early Cretaceous outcrop is about six-feet long and one-foot in diameter. It gently descends in a semi-spiral, ending in an enlarged chamber.
Martin later found two similar trace fossils in the same area.
The Victoria fossils are about 110 million years old, around the time that Australia split with Antarctica, and dinosaurs roamed in prolonged polar darkness along forested southern Australia river plains.
It was one of the last times the Earth experienced global warming, with an average temperature of 68 degrees Fahrenheit - about 10 degrees higher than today.
The age, size and shape of the likely burrows led Martin to hypothesize that they were made by small ornithopod dinosaurs, which were herbivores that were prevalent in the region.
These ornithopods stood upright on their hind legs and were about the size of a large, modern-day iguana.
"It's fascinating to find evidence connecting a type of behavior between dinosaurs that are probably unrelated, and lived in different hemispheres during different times," Martin said.
"It fills in another gap in our understanding of the evolution of dinosaurs, and ways they may have survived extreme environments," he added. (ANI)