Anthony Martin of Emory University points to new fossil evidence of dinosaur burrows in Victoria, Australia.
Credit: Emory University
SYDNEY: Dinosaur burrows found in Australia add to growing evidence that some dinosaurs may have developed behaviours to help cope with climate change.
The find, to be published in the journal Cretaceous Research later in July, was made by palaeontologist Anthony Martin of Emory University in Altanta, USA. It follows the first trace fossil of a dinosaur burrow made in Montana by Martin and colleagues in 2006.
It suggests that burrowing behaviours 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.
"This research helps us to better understand long-term geologic change, and how organisms may have adapted as the Earth has undergone periods of global cooling and warming," said Martin, a senior lecturer in environmental studies at Emory. Martin is also an honorary research associate at Monash University in Melbourne.
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 fossilised burrow in southwestern Montana. They later named the dinosaur species Oryctodromeus cubicularis, meaning "digging runner of the lair".
The researchers hypothesised 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 coast of Australia's southern state of Victoria, which marks the seam where Australia once snuggled against Antarctica. Lower Cretaceous strata of Victoria have yielded the best-documented assemblage of polar dinosaur bones in the world.
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.
"I stared at it for a long time," recalls Martin. "In palaeontology, the saying, 'where luck meets preparation' really holds true."
The probable burrow etched into the Early Cretaceous outcrop is about 182 cm long and 30.5 cm 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.
