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Running, bipedal? Re: Baby dinosaur tracks from Morrison





On Mon, 1 Nov 2010, bh480@scn.org wrote:

From: Ben Creisler
bh480@scn.org

In case this news story has not been mentioned yet:

http://www.genengnews.com/industry-updates/morrison-
natural-history-museum-discovers-baby-sauropod-
tracks/98965127/

Mentions tracks from baby apatosaurs with possible
evidence that baby sauropods sometimes ran on hindlimbs
only.

Link not found. However, a similar (might even be the same) article
is here:

http://www.geosociety.org/news/pr/10-63.htm
Morrison Natural History Museum Discovers Baby Sauropod Tracks
Tracks of a Running Bipedal Baby Brontosaur?

Staff at the Morrison Natural History Museum have again discovered infant dinosaur footprints in the foothills west of Denver, near the town of Morrison. Dating from the Late Jurassic, some 148 million years ago, these tracks were made before the Rocky Mountains rose, when Morrison was a broad savanna full of dinosaurs.

The fossil tracks represent infant sauropods, according to discoverer Matthew Mossbrucker, the museum's director. Sauropods are giant, herbivorous long-necked dinosaurs, sometimes known as "brontosaurs."
...
Leading paleontologist Dr. Robert T. Bakker of the Houston Museum of Natural Sciences (who also serves as the Morrison Museum's volunteer curator of paleontology) remarks, "The latest discovery by the Morrison Natural History Museum is a tribute to Director Matt Mossbrucker and his crew of sharp-eyed volunteers. Never before has science given us such an intimate glimpse of baby brontosaurs - a window into Jurassic Family Values."

"Three years ago the Morrison Museum crew detected adult and baby Stegosaurus, hinting that the area had been near a stego nesting ground. The new baby sauropod tracks may well be the very smallest, youngest apatosaurs ever discovered, in the form of bone or trackways. Was Morrison an apatosaur nursery? The evidence is fascinating," muses Bakker.

The tracks are ovular and can be nearly eclipsed by a coffee mug, suggesting that the infant sauropods were about the size of a small dog. While one animal left average walking footprints, another infant dinosaur ran parallel to adult tracks.

The running trackway is unusual. "The distance between each step is two-times wider than what we observe in walking tracks indicating the animal was at a low speed run," remarks Mossbrucker. "I am not aware of any running sauropod tracks anywhere." Nor is Bakker.

Surprising to Mossbrucker and colleagues is that the running trackway demonstrates only hindpaw tracks. "Perhaps while the little dinosaur was running the hindpaw eclipsed and crushed the frontpaw track leaving no trace, or perhaps this critter was running only on its hind paws," Mossbrucker states. The walking-gait tracks do show a forepaw track.

Tail drag troughs are absent on both trackways, which is not surprising, because most sauropod trackways do not show a tail drag mark. This evidence, combined with detailed studies of the tail point, lead researchers to believe that sauropod tails were carried off the ground.

"In the end, we might have a baby sauropod that is running like a Basilisk lizard, a modern lizard that is mostly a quadroped, but when spooked it runs on its hindlegs." Studies are underway to understand the biomechanics of Morrison's sauropods and what a running baby sauropod would look like.
...