Scientists were wrong about this strange mammal for nearly 40 years

A beautifully preserved fossil from Mongolia’s Gobi Desert has solved a mystery that puzzled paleontologists for nearly 40 years. Tamirkhan balcarceli shows that zhelestids were not early relatives of modern placental mammals, despite having teeth that seemed to suggest they were. Instead, the rabbit-like animal belonged to a separate lineage of small Cretaceous mammals.

Scientists were wrong about this strange mammal for nearly 40 years. Scientists were wrong about this strange mammal for nearly 40 years Science News from research organizations Scientists were wrong about this strange mammal for nearly 40 years A remarkably complete “Cretaceous rabbit” fossil from Mongolia has overturned a 40-year-old idea about early mammal evolution. The newly identified species, described in the journal Nature by researchers from the American Museum of Natural History, Stony Brook University, University of Arizona, and Arcadia University, provides new evidence about an extinct group of mammals called zhelestids.

For decades, many scientists thought zhelestids were closely related to modern placental mammals. Instead, zhelestids appear to have belonged to a very different branch of early mammals, overturning an interpretation that was based largely on fossil teeth. "This discovery illustrates why fieldwork remains indispensable to understanding life’s history," said the study’s lead author Andres Giallombardo, who found the specimen as a graduate student on a Museum-sponsored expedition in 2004.

"It was the thrill of a career to find a new species so completely preserved that also solves a longstanding scientific problem, and a reminder that the Gobi Desert, which is well known for fossils, continues to change science." Fossil Teeth Pointed Scientists in the Wrong Direction Zhelestids have been known to paleontologists for nearly 40 years, but most discoveries consisted of isolated teeth or incomplete remains.