Morganucodon watsoni

The Morganucodon is an early mammal-like creature that lived during the Late Triassic to Early Jurassic period, approximately 205–195 million years ago. About the size of a modern shrew, it measured around 4 inches long and weighed only a few ounces. Morganucodon is notable for its transitional features between reptiles and mammals, including differentiated teeth (incisors, canines, and molars) and a jaw structure that incorporated both reptilian and mammalian elements.

It likely fed on insects and small invertebrates, using its sharp teeth and nocturnal habits to avoid predators. Morganucodon represents a pivotal step in mammalian evolution, showcasing traits that would later define true mammals, such as improved hearing and a more advanced jaw joint. Its fossils provide key insights into how early mammals emerged and adapted in a dinosaur-dominated world.