The Big Word of the Month, Odontochelys, is a mouthful and is the genus name of the a newly discovered fossil turtle. It was found in China in late 2008. Odontochelys semitestacea is the oldest known example of turtles and the specimen differs from modern turtles in two important ways.
First, the species has a toothed mouth rather than the toothless beak of present day turtles. The “odonto” in the name comes from the Greek word for “teeth”.
Secondly, this 220 million year old turtle fossil has a fully formed plastron(the underside of the shell) but an incomplete carapace (the top of the shell). This morphology helps settle a long standing debate in Biology and suggests that the armored underside of the turtle came first in the evolutionary history of the group. Scientists theorize that the plastron may have provided protection from aquatic predators in Mesozoic habitats.
Image from Wikimedia commons