AboutDavid Prus Expertise I can answer any general questions about dinosaurs and on prehistoric mammals in the Cenozoic. I also know a bit about the media's various depictions of dinosaurs and their inaccuracies. I don't know much about "microfauna"-small animals, or about Paleozoic besides some knowledge about Permian animals. Plants are right out, I'm afraid.
Experience I have been interested in dinosaurs for most of my life, own a large collection of scientific papers and books on the subject, and am a member of the Field Museum in Chicago.
Education/Credentials I am in college, but studied biology and geology both in high school and as a personal effort.
Question Hi David! I'm delighted to have found this site as I have so many questions!
I was reading AD Walker's classic text on Ornithosuchus longidens. He describes how the entire body of this animal, from skull to tail, was considerably deeper than broad. This immediately reminded me of the shape of most fish, and I wondered whether anyone had seriously considered the possibility that this was a partly aquatic species? Laterally compressed tails, as in crocodilians, are often cited as evidence of swimming. I know Ornithosuchus lacks some of the other specialized adaptations seens in crocs and phytosaurs, like eyes and nostrils situated dorsally, so it presumably wouldn't have lurked in ambush like a croc, but it occurred to me that if it were a more active predator, swimming after underwater prey, then it might not have needed these adaptations. Walker also discusses whether the animal walked on two or four legs, and says that there are problems with both theories; its centre of gravity was too far forward for bipedal locomotion at all but the highest speeds, but if it were on all fours it would have problems in that its hindlimbs were so much longer than the forelimbs that the forward movement or "recovery stroke" of the hindlimbs would be impeded by the ground. Again I thought that these issues might be less important to a creature that did most of its hunting in water anyway. Apparently its habitat in late Triassic Scotland was fairly arid, but there would have been enough large bodies of fresh water around for specialized aquatic predators like phytosaurs to make a living, so presumably Ornithosuchus could have shared their habitat and avoided competition with different hunting habits and prey choice. However I'm sure that if this scenario was at all feasible someone wiser than me would have thought of it by now. There must be some gaping flaw in my logic but I don't know what it is. Your help would be very much appreciated!
Answer Fascinating idea. There are a couple problems; the teeth are curved backwards and the head is short. These aren't adaptations for hunting fish; most fish eaters had straight, smooth teeth like crocodiles. The nostrils are low in the skull and the tail is thin and whiplike; both suggest it was terrestrial. Furthermore, it was the largest predator in its area and on the ground, whereas phytosaurs and large amphibians were the main aquatic predators. Finally, the other reptiles found in the same area were strictly terrestrial
Still, you have an interesting idea, and I have to give you credit on your hypothesis.
