Mammal-like reptile survived much longer than thought

Researchers have uncovered dozens of fossilized teeth in Kuwajima, Japan, and identified this as a new species of tritylodontid, an animal family that links the evolution of mammals from reptiles. The finding suggests that tritylodontids co-existed with some of the earliest mammal species for millions of years, overturning beliefs that mammals wiped out mammal-like reptiles soon after they emerged.
Paleontology News — ScienceDaily