On an expedition in Scotland, researchers recently discovered the fossilized remains of a mouse-sized mammal dating back around 170 million years to the Middle Jurassic. The fossil represents a lower jaw belonging to a species of 'stem therian' mammal called Palaeoxonodon that was previously known solely from isolated teeth.
Palaeoxonodon is an important species for understanding the evolution of molar teeth in modern mammals.
The latest discovery indicates that three species previously described on the basis of individual fossilized teeth actually belong to just one species.
This is an image of the lower jaw of Palaeoxonodon. Credit: Dr. Roger Close
"This new fossil provides a wealth of novel information about an important species of early 'pre-tribosphenic mammal," said Dr. Roger Close, lead author of the Palaeontology study.
source: Wiley