Until recently, Orthacanthus gracilis could have been considered the ‘John Smith’ of prehistoric shark names, given how common it was. Three different species of sharks from the late Paleozoic Era — about 310 million years ago — were mistakenly given that same name, causing lots of grief to paleontologists who studied and wrote about the sharks through the years and had trouble keeping them apart. But now a professor has finished the arduous task of renaming two of the three sharks — and in the process rediscovered a wealth of fossil fishes that had been stored at a museum for years but had been largely forgotten.