Photos: Skull of Enigmatic Mammal That Lived With Dinosaurs

Until now, researchers only had a few teeth and lower jawbones of the gondwanatherians, an extinct group of mammals that lived during the time of the dinosaurs. The discovery of a well-preserved skull of a new gondwanatherian species, called Vintana sertichi, in Madagascar provides new insights into these mysterious creatures. Its skull suggests that the mammal had large eyes, a good sense of smell, high-frequency hearing and an herbivorous diet. [Read full story on the Madagascar mammal

Gondwana mammal

An artist's interpretation of the mammal Vintana sertichi, which lived during the time of the dinosaurs, about 66 million to 72 million years ago, on the ancient supercontinent Gondwana. (Photo credit: Luci Betti-Nash.)

Life-size replica

A cast of the Vintana sertichi skull next to a life-size reconstruction of the mammal. The skull is about 5 inches (13 centimeters) long, making it the largest known primitive mammal to live during that time period on the supercontinent Godwana. (Photo credit: Joseph Groenke | Stony Brook University, Sculpture credit: Gary Staab | Staab Studios.)

Fragile skull

Researchers prepare to remove the rock surround the skull of Vintana sertichi. The team accidently found the skull of the mysterious creature in Madagascar in 2010. (Photo credit: Joseph Groenke.)

Careful preservation

Researcher Joseph Sertich, now a vertebrate paleontologist at the Denver Museum of Nature & Science, initially covered a large block of fossils with several layers of burlap soaked in plaster. The team didn't realize that the block contained the mammal's skull until they discovered it during a CT scan. (Photo credit: Joseph Groenke.)

Toothy remains

The teeth of the mammal suggest that it had an herbivorous diet of roots, seeds or nutlike fruits. Brown enamel once crowned the teeth, but have since been worn down to small brown islands, said Joseph Groenke, a lab technician at Stony Brook University in New York. (Photo credit: Joseph Groenke.)

Skull shape

The shape of the skull suggests that gondwanatherians are related to multituberculates, a group of rodents that lived in the Northern Hemisphere during the time of the dinosaurs. (Photo credit: Joseph Groenke.)

Teeth magnified

Like other herbivorous mammals, Vintana sertichi had high-crowned check teeth that helped it eat abrasive plant material. It's likely that the mammal was older, and had worn down its teeth, the researchers said. (Photo credit: Joseph Groenke.)

Sideways view

The skull also sports large eye sockets. Although sometimes eye sockets are partially filled with fat, it's likely that the mammal had large eyes that could see well in dim conditions, said researcher David Krause, a professor of anatomical sciences at Stony Brook University in New York. (Photo credit: Joseph Groenke.)

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Laura Geggel

Laura is the archaeology and Life's Little Mysteries editor at Live Science. She also reports on general science, including paleontology. Her work has appeared in The New York Times, Scholastic, Popular Science and Spectrum, a site on autism research. She has won multiple awards from the Society of Professional Journalists and the Washington Newspaper Publishers Association for her reporting at a weekly newspaper near Seattle. Laura holds a bachelor's degree in English literature and psychology from Washington University in St. Louis and a master's degree in science writing from NYU.