A skull of a massive, ancient, groundhog-looking mammal could shed new light on the evolutionary history of mammals.
In a paper published Wednesday in the journal Nature, scientists report that they have discovered remains of a mammal that lived 66 million years ago in what is today Madagascar. The 20 pound creature vastly outweighed nearly all other mammals of its era.
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“It was a monster,” David Krause of Stony Brook University in New York, who led the research team, told the Associated Press. “It looks like a big groundhog.”
Krause and his colleagues named the mammal Vintana sertichi. “Vintana” means “luck” in Malagasy, and was chosen because of the way the skull was discovered by surprise when the scientist were doing a CT scan of a large sandstone block to look for fish fossils. “We were astounded to see a mammal skull staring back at us on the screen,” Dr. Krause told Reuters.
“It was dawning on me that I was experiencing the most incredible bit of luck I had ever been part of,” Joe Groenke added, Krause’s technician and the first to view the CT images.
The second part of the animal’s name honors Joseph Setrich, now a curator at the Denver Museum of Nature & Science, who in 2010 collected the sandstone block.
The 5-inch skull gives scientists their first good window into a poorly understood group of ancient Southern Hemisphere mammals, named gondwanatherians, that had until known, been known only from isolated teeth and bits of jaw. They went extinct long ago, without leaving any descendants behind.
Vintana is only distantly related to today’s mammals and was not a member of any of the three existing groups: placentals, marsupials and monotremes, reports Christian Science Monitor. “It is one of those evolutionary experiments in ‘mammalness’ that did not make it,” Krause told Reuters. “In essence, it really shakes up the early mammalian family tree and helps to reorganize it.”
The closet modern animal to Vintana is a large, semi-aquatic South American rodent called nutria, Krause told Reuters.
Judging the giant mammal’s well-preserved skull, it was a plant eater with strong jaws, keen sense of smell, well-developed hearing and terrific eyesight under low light conditions, they wrote in the paper.
“It would have been a very fine hors d’oeuvre” for a dinosaur, Krause told the AP.