The mystery solved
In 2011, a newly discovered extinct mammal named Cronopio was the key that unlocked the mystery of the burrowing enigma. Discovered by co-author Rougier in South America, Cronopio belongs to the Meridiolestida, a little-known group of extinct mammals found in the Late Cretaceous and early Paleocene (10060 million years ago) of South America. Not only were Cronopio and Necrolestes found to have remarkable similarities, they are the only known mammals to have single-rooted molarsmost mammals have double-rooted molars. This conclusively showed that Necrolestes was neither a marsupial nor a placental mammal, and was in fact the last remaining member of the Meridiolestida lineage, thought to have gone extinct 45 million years earlier.
If we didnt know those fossils, says Wible of Cronopio, we might have come to the same conclusion that everybody else hadthat the relationships of Necrolestes were unknowable.
The mass extinction that ended the Age of Dinosaurs wiped out thousands of species. Included in the devastation were the Meridiolestida, the mammal group to which Cronopio and Necrolestes belong, cutting s
|Contact: Leigh Kish|
Carnegie Museum of Natural History