Scientists in China have unearthed a nearly complete skeleton of a “Jurassic rat” — a 160 million-year-old creature — which they say is one of evolution’s most successful mammals.
The fossil of the extinct rodent-like creature is helping to explain how multituberculates — the most evolutionarily successful and long-lived mammalian lineage in the fossil record — achieved their dominance, researchers said. This fossil find — the oldest ancestor in the multituberculate family tree — represents a newly discovered species known as Rugosodon eurasiaticus.
The fossil unearthed by Chong-Xi Yuan from the Chinese Academy of Geological Sciences in Beijing and colleagues reveals teeth that were adapted to gnawing plants and animals alike, as well as ankle joints that were highly adept at rotation. Researchers suggest that R eurasiaticus paved the way for later plant-eating and tree-dwelling mammals. The multituberculates flourished during the Cretaceous era, which ended over 60 million years ago.