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 1)what was the apex predator in north america 90 mya? 2)what was the apex predator in south america,africa,asia,india 65 mya? 3)if dryptosaurus and appalachiosaurus were primitive tyrannosaurids why did they lived 70 mya when already more advanced tyrannosaurids had evolved (albertosauru,daspletosaurus) did thet competed each other? Thanks
Answer 1) Good question. Much of North America was covered in the inland sea at the time, but there are some dinosaur sites. This was the time of faunal turnover when carnosaurs like Acrocanthosaurus were replaced by tyrannosaurs. No predator fossils are known currently, but there were probably some primitive tyrannosaurs and dromeosaurs acting as predators.
2) South America-Carnotaurus, a horned, heavily built abelisaur
Africa-unknown. The last predators are from 90 mya-Carcharodontosaurus and several abelisaurs. If Africa had a faunal turnover as South America did, then probably the descendants of abelisaurs like Rugops and Kryptops
Asia-Tarbosaurus, Tyrannosaurus' Mongolian sister genus
India-Indosuchus, Rajasaurus, two 30-foot abelisaurs
3) These primitive tyrannosaurs were sheltered from being outcompeted by more advanced species by the inland sea, which prevented their more powerful relatives from taking over. We see this in South America and Africa in the Cretaceous-more primitive ceratosaurs and carnosaurs hold out while the tyrannosaurs take over elsewhere. Even in mammalian times we see this-giant predatory marsupials, crocodiles, and birds were the top predators in islands like South America and Australia. When placental predators(cats, dogs, and humans) appeared, the indigenous species were pushed out.
