Scientists have unearthed the fossilized skull of the second-largest mammal alive during the age of the dinosaurs. The creature lived between 66 million and 72 million years ago and belonged to a group of mammals known as gondwanatherians, which roamed Gondwana, a landmass that, starting about 180 million years ago, broke apart into South America, Australia, Antarctica, Africa, Arabia, Madagascar, and India. Previously, researchers knew about gondwanatherians only from teeth and bits of jawbones. But in a study published online today in Nature, a team describes a complete skull of a new species from the group. The 12.4-centimeter-long cranium was unexpectedly recovered from a block of sandstone full of fish fossils excavated in Madagascar. Based on the length of the fossil, the creature (depicted at left and center of artist’s representation) probably weighed about 9 kilograms, likely making it the largest mammal of its time. Placed in the new genus Vintana (the Malagasy word for “luck”), the plant-eating beast had ever-growing, rodentlike front teeth, molars whose grinding surfaces were tilted slightly outward, and a bite force about twice that of modern rodents of a similar size. Surprisingly, the nose, palate, and rear portion of the skull contain bones long presumed by paleontologists to have been lost before mammals evolved, the researchers note. A CT scan of the braincase suggests that about 14% of Vintana’s brain was devoted to interpreting odors, so the creature apparently had a keen sense of smell. Its relatively large eyes, as well as certain features in the creature’s inner ear, suggest the creature was agile and fast—the better for this small plant eater to dodge dinosaurs in search of tasty morsels.