Burrowing Dinosaurs

We tend not to think of dinosaurs as creatures that needed to hide, but a specialist in trace fossils, that is, fossil tracks, trails, and footprints, has identified fossils of a small adult and two juvenile dinosaurs in what he interprets as a fossil burrow in 95-million year old sedimentary rocks in Montana.

Ichnologist Anthony Martin of Emory University in Georgia presumes that the dinosaurs used the burrow to protect themselves from predatory dinosaurs.

More recently Martin identified similar burrow structures in 105-million year old sedimentary rocks from Victoria, Australia. The burrows are about 2 meters long and 30 centimeters in diameter and spiral downward to end in an enlarged chamber.

During the Early Cretaceous Period the average annual temperature in Victoria was probably less than 20 C (68 F). So in addition to serving as protection from predators, a burrowing habit may have served to protect the cold-blooded reptiles from freezing winter temperatures.

Research by Anthony Martin, published in Cretaceous Research (October, 2009)

Dinosaurs Down Under

The Mesozoic Era is more widely known as “The Age of the Dinosaurs” because it was during this time in Earth history that dinosaurs and other reptiles emerged as the dominant life forms, occupying just about every ecological niche and ranging from tropical to near-polar latitudes.

Dinosaurs have been found on every continent, but North America and China enjoy especially diverse and abundant dinosaur faunas, reflecting favorable living conditions for dinosaurs as well as favorable conditions for their preservation.

During the Mesozoic, Australia was located at high latitudes in the southern hemisphere, and was in the process of separating from the supercontinent Pangea. Dinosaur discoveries Down Under are rare, and each new dinosaur find is newsworthy, so the recent discovery of three new Australian dinosaurs is a quantum leap in understanding the geographic range of southern hemisphere dinosaurs.

Reference: Hocknull SA, White MA, Tischler TR, Cook AG, Calleja ND, Sloan T, Elliott E. (2009) New Mid-Cretaceous (Latest Albian) Dinosaurs from Winton, Queensland, Australia. PLoS ONE 4(7): e6190. doi:10.1371/journal.pone.0006190

Photo credit: http://paleonews.files.wordpress.com/2009/07/2009-07-03-australian-dinosaurs.jpg