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 albertosaurus died out 70mya and tyrannosaurus first appeared 68mya. during that 2my period who would be the apex predator? i've noticed this in other occasions-( north ameeica-allosaurus 144mya,next apex predator utahraptor 131mya,10my). when predatory dinosaurs attacked their prey did they bite in some particular parts of the body of their prey(neck region,hips) or weren't that smart? purrusaurus and other giant crocodylomorphs lived 8 mya in south america that was covered by a giant inland sea. also megalodon lived in south america that time. did these creatures come into conflict? which one of them would have the advantage? Thanks.
Answer Remember, fossils only show a fragment of geological history. They might have been contemporaries for a brief amount of time.
Dinosaur hunting tactics are hard to predict, considering the rather random method used by crocodiles and the more precise methods used by birds. Still, I would say they would target the head, limbs, back, and especially the neck. There are bite marks on hadrosaur tails, stegosaur plates, Triceratops frills and hips, and sauropod limbs and backbones, but it's hard to tell whether the bites came from feeding or scavenging.
There is one example, though, of a predator caught in the act: the "Fighting Dinosaurs" fossil shows a Velociraptor slashing with its claws at the neck and belly of a Protoceratops.
Purusasaurus probably came in contact with Megalodon about as often as saltwater crocodiles come into contact with great white sharks in Australia today. The outcome of any croc vs shark fight is entirely dependent on the water level. If it's fresh, warm or shallow, the croc can maneuver better and defeat the heavier shark. If it's too salty, cold, or deep, the shark can maneuver its body enough to counter and destroy the croc. It'd be rare and dangerous for both opponents, so they probably avoided each other most of the time
