Researchers from Okayama University of Science, Tokyo City University, the Natural History Museum, Kishiwada City (Osaka Prefecture), and other institutions have uncovered four fossil bones that went unrecognized for roughly three decades. The bones were found inside rock containing mosasaur remains collected in Kishiwada City, Osaka Prefecture.
One of the newly identified fossils is the premaxilla, the bone at the very front of the upper jaw. This marks the first time a premaxilla has been confirmed in a mosasaur fossil discovered in Japan. Other unusual anatomical features in the remains do not match those seen in previously described mosasaurs, suggesting the animal could represent a species that is new to science.
Ancient Marine Reptile Fossils Reexamined
Mosasaurs were large marine reptiles that inhabited oceans around the world during the Late Cretaceous, approximately 98 to 66 million years ago.
The fossils in this study were first discovered between 1990 and 1992 in Sobura, Kaizuka City, Osaka Prefecture. They were later preserved at the Natural History Museum, Kishiwada City. When researchers recently returned to pieces of rock that had not yet been fully prepared, they found four fossil bones still embedded in the surrounding material.
