Fossilized remains of "burrowing" dinosaur found in Montana

Wednesday, March 21, 2007 

An artist's illustration shows an Oryctodromeus head. (Illustration by Lee Hall).

The remains of a fossilized "burrowing" dinosaur have been found in Lima, Montana and scientists say that the dinosaur may have been forced to dig in an effort to survive the asteroid impact that wiped out the dinosaurs nearly 65 million years ago.

One full grown dinosaur and two young ones are the first evidence of any burrowing dinosaur to be discovered by scientists and is also the first evidence that a dinosaur cared for their offspring in dens.

"Burrowing behaviour allows vertebrates to escape harsh environmental conditions. Small dinosaurs could potentially have withstood severe conditions, such as drought or ... temperature extremes. Survival of terrestrial vertebrates at the end-Cretaceous event has been attributed to sheltering behaviour, with the extinction of non-avian dinosaurs resulting from their inability to find an appropriate cover," said Montana State University's chief researcher, David Varricchio.

The new dinosaur has been called "Oryctodromeus cubicularis" which is being defined as the "digging runner of the lair."

"Here we have the burrow, den, an adult with traits for digging, and two juveniles, all in the same place. It doesn't get much better than that," said researcher at Emory University, Anthony Martin.

The remains were found in an area that was once covered by an ancient flood, but Varricchio states that the flood was not the cause of the dinosaurs death.

"The bones are disarticulated; they are not in life position. It's not like they were sitting in the burrow and a flooding event filled the chamber with sediment and they were entombed. They must have died, undergone decay and then the burrow was filled," added Varricchio.

The fully grown dinosaur is at least 2.1 meters long and weighed nearly 22 to 32 kilograms. Scientists say that the dinosaurs are nearly 95 million years old and are from the Cretaceous period of dinosaurs. In evolutionary terms, the dinosaur lived just before the asteroid impact that made dinosaurs extinct.

Sources

• James Randerson. "Fossil reveals a caring, sharing dinosaur" — Hindu, March 21, 2007
• "Asteroid may have forced dinosaur to dig" — The Australian, March 21, 2007
• Evelyn Boswell. "Burrowing, digging dinosaurs found in southwest Montana" — Montana State University, March 20, 2007