Researchers working on the island of Madagascar have found evidence of a 30-foot dinosaur with knife-blade teeth that ate members of its own species — perhaps the first clear case of dinosaur cannibalism.

The two-ton horned carnivore, Majungatholus atopus, lived 65 million to 70 million years ago, a time of prolonged drought and periodic floods on the island’s semiarid northeastern plains.

“It was a tough time, and Majungatholus probably had to capitalize on whatever was available,” said Macalester College geologist Raymond Rogers, who led the research team. “Of course animals with teeth like Majungatholus would get meat wherever they could” — including from Majungatholus itself.

Examining remains from a wide variety of animals in the fabled “bone-beds” of Madagascar’s Maevarano formation, a seam of fossil-rich sedimentary rock 35 to 50 feet deep, the team found bones from two of the carnivores that were scored with tooth marks that could only have been made by another Majungatholus.

The Madagascar find, reported Wednesday in the journal Nature, is the first unequivocal evidence of dinosaur cannibalism ever described. Fossils more than 200 million years old from New Mexico suggest that a smaller species of dinosaur may have eaten its young, but that evidence has recently been questioned.

Nevertheless, dinosaur cannibalism is “not really surprising,” said Hans-Dieter Sues, vertebrate paleontology curator at the Carnegie Museum of Natural History. “Most modern reptiles show cannibalism as a very common occurrence.” He noted that young Komodo dragon lizards flee to the treetops to avoid being eaten by their full-grown relatives.

Indeed, added Rogers, at least 14 mammal species today are known for cannibalism. These include large cats like lions, tigers, leopards, cougars and lynx; wild dogs, including hyenas, golden jackals, wolves, coyote and dingo; and red fox, arctic fox, brown bear and grasshopper mice.

The Majungatholus report is the latest to emerge from a 10-year project studying the prehistoric animals of Madagascar. Madagascar, an island about 300 miles off the coast of East Africa, is celebrated among biologists for the uniqueness of its plant and animal life.