Nipponites mirabilis are some of the most unusual-looking ammonites. Another heteromorphic species, fossils have been found in rocks that date to the Late Cretaceous in Japan. The unusual alternating ...

Based on the fossil record ... than an inch to as large as nine feet wide. Some ammonites had long, straight shells, while others had helix-shaped shells. Most species, however, had coiled ...

“We’d noticed these fossils before, but this time, Kolby brought a very large iridescent piece to me. It was clear he had discovered something extraordinary with this ammonite fossil.

He said he stumbled upon the fossil while searching for ammonite fossils for his doctoral ... similar to a sea turtle or humpback whale. The shape of the spine also indicates that the species ...