Tuesday, 24 April 2007

Shark vs. Dinosaur

A recent find in Utah reveals a large prehistoric lake around 200 million years with an amazing fossil cache including an enormous, carnivorous dinosaur and several species of sharks. Anatomical features of the dinosaur suggest it specialized in eating fish, including sharks and huge bony fish, meals which palaeontologist James Kirkland describes as “like biting through chain mail [since] fish in the past were more armored than they are today."

The dinosaur, a relative of the crested dino Dilophosaurus, was about 20 feet long and so would have been a formidable adversary for its ferocious prey. The dinosaur’s slender, serrated teeth are quite unusual and only found in dinosaurs like Spinosaurus and Suchimimus.

Dilophosaurus was well adapted to being a fisherman. Its nasal openings retracted back from the end of its snout so that it could, like today's crocodiles and alligators, still breath when its mouth was underwater.

There are clear tracks and claw scrapes showing the dinosaur wading into the lake to catch its prey. "We have counted over 3,000 individual claw marks and toe scrapes that show incredibly detailed preservation," reveals palaeontologist Andrew Milner. "We can see details of cuticle on the tips of claws, skin impressions, scale scratch lines and where claw cuticle was overlapped by the fleshy toe pads at the end of the toes."


Laelaps said...

Wow! This is fantastic stuff; I'm glad that we're now at the point where whole ecosystems can be reconstructed rather than simply saying "I found a dinosaur over there" and leaving it at that.

Zach Miller said...

Now I'm interested to know if this predator is a ceratosaur, like the press release compares it to, or if it's an early megalosaur, and by that I mean early spinosaur. Those teeth are very diagnostic, after all.

Sordes said...

Well, I thought since many years that the jaw and tooth morphology of Dilophosaurus would well fit a fish-eating behavior, and that those old ideas that it was a specialized scavenger are really stupid, not only because such a thing like full-time scavenging in terrestrial carnivores doesn´t exist, but also because the long and slender teeth would be very bad in dealing with leatheriy skin and meat. The slender body and the long neck made Dilophosaur and its relatives probably even more monster-heron like than spinosaurids.

Anonymous said...

Why is it that prehistoric fish eaters are assumed by many to have small bite forces when as this article says prehistoric fish had armored scales?