Pseudorthoceras, possibly Mooreoceras
Pseudorthoceras was first described by G. H. Girty in 1912. It was part of a paper describing new species of Pennsylvanian fossils from the Wewoka Formation of Oklahoma. The species appeared 376 million years ago and disappeared during the Permian–Triassic extinction event 252 million years ago. This extinction, known asRead More →