U-M researcher co-discovers meat-eating dinosaurs in Africa
ANN ARBOR, Mich.—A University of Michigan paleontologist is part of a team announcing the discovery of two new species of meat-eating dinosaurs. The fossil finds—the backbone of one species and the oddly wrinkled skull of another—provide new insights into how and when the continents of Africa, South America and India split apart long ago.
The 95-million-year-old skull, found in the African Sahara, is from a meat-eating dinosaur species whose cousins lived as far away as South America, Madagascar and India. Along with the backbone, which is from another new meat-eating species discovered on a separate expedition, the skull helps fill critical gaps in the evolution of carnivorous dinosaurs in Africa. Both species are described in a paper published online June 2 in the Proceedings of the Royal Society of London, Biological Sciences. The paper's authors are National Geographic Explorer-in-Residence Paul Sereno, who led the expeditions, U-M paleontologist Jeffrey Wilson and Jack Conrad of the University of Chicago. The July issue of National Geographic magazine also will include an article on one of the dinosaurs.
Sereno, a paleontologist and professor at the University of Chicago, has named the ancient skull Rugops primus, meaning "first wrinkle face." Measuring about 30 feet long in life, the animal had a short, round snout and small, delicate teeth, he said. It belongs to a group of southern carnivorous dinosaurs called abelisaurids.
The head of Rugops had a tough covering of scales or surface armor and was riddled with arteries and veins, leaving a crisscross of grooves on the skull. "It’s not the kind of head designed for fighting or bone-crushing," Sereno said. Instead, he believes Rugops was a scavenger, using its head to pick at carrion rather than fighting other animals for food.
"What's really bizarre—and we aren't yet certain what this means—is that there are two rows of seven deep holes along each side of Rugops's snout," said Wilson, an assistant professor of geological sciences. "The wonderful thing about fossils is that sometimes you're confronted with anatomy that's unique, so you're forced to use your comparative anatomy skills and reasoning to figure out what they might represent."
Using those skills, Sereno and Wilson speculate that the holes may have anchored ornamental structures that the animal used for display. "This may have been a scavenger with head gear," Sereno said. "It’s really a beautiful intermediate species of the group that later evolved into the first horned predators."
The second new dinosaur species, named Spinostropheus gautieri, was found in 135-million-year-old rocks in Niger. The fossil, an articulated (connected) spine, represents an ancient relative of Rugops and other abelisaurids. These finds provide fresh evidence about when Africa, Madagascar, South America and India split from each other as a result of continental drift. Before these discoveries, abelisaurids were virtually unknown from Africa, leading some scientists to suggest that Africa had split off first from the southern landmass Gondwana, perhaps as early as 120 million years ago. The new fossils indicate that Africa and the other southern continents that formed Gondwana separated and drifted apart over a narrow interval of time, about 100 million years ago.
"It's hard to convey how little we knew—and still know—about Africa during the end of the dinosaur era," Wilson said. "But the expeditions that Paul Sereno has led have really begun to clear up questions about what was living on Africa during the time of the dinosaurs. Now we're replacing the question marks with fossils."
This research was funded by National Geographic, the David and Lucile Packard Foundation, the Pritzker Foundation and Nathan Myhrvold.
Contact: Nancy Ross-Flanigan