Japanese scientists have discovered a jaw fragment of a 112-million-year-old primitive mammal from the early Cretaceous period. The fossilized bone fragment was discovered in Hyogo Prefecture.
The little creature, named Sasayamamylos kawaii, belongs to an ancient biological group known as Eutherian mammals, which gave rise to all placental mammals, according to the international press.
The jaw has pointy, sharp teeth and molars in a proportion similar to that found in modern mammals, said paleontologist Brian Davis of Missouri Southern State University, who was not involved in the study.
With four sharp, pointy teeth called pre-molars, and three molars with complex ridges, the jaw has the same number of each type of tooth that is found in modern placental mammals who live in our times.
Davis thinks these teeth would have allowed the Sasayamamylos to break faster through the exoskeletons of beetles or other insects, eat their meat and thus get quickly the energy they needed while running around the feet of giant dinosaurs.
The jaw was originally discovered in 2007 by fossil hunters, and was turned over to a local museum, the local press reports.