CHICAGO (Reuters) - Fossils from two newly discovered meat-eating dinosaurs that lived in the Sahara Desert 110 million years ago paint a fearsome picture of life in Africa's Cretaceous period, which appears to have been teeming with unusual carnivores.
University of Chicago paleontologist Paul Sereno unearthed Kryptops palaios, a short-snouted, hyena-like beast, and Eocarcharia dinops, a shark-toothed, bony-browed killer in a 2000 expedition.
Both were about 25 feet in length -- and on the prowl for meat.
"These are two of three that we dug up. To have three large predators in this area is really extraordinary," said Sereno, who describes the dinosaurs in the scientific journal Acta Palaeontologica Polonica.
The third, the fish-eating, sail-backed Suchomimus or "crocodile mimic," was found in 1997.
"They were also living alongside a 40-foot (12-metre) crocodile, SuperCroc. They lived in a vicious time," he said.
Sereno said the animals lived in the southern landmass that was known as Gondwana, where distinctive meat-eaters arose, many of which bear no likeness to the better-known North American predator of the time, Tyrannosaurus rex.
Kryptops, or "old hidden face," was named because of the horny material called keratin that covered its face. This fast, two-legged creature specialized in gnawing.
"We think the face was covered with a bill-like material. It would have looked pretty much like the bill of a bird," Sereno said.
Kryptops was a scavenger and had a uniform series of relatively pointy teeth and a short snout. "The idea was that the animal was sticking its head into carcasses," he said.
Eocarcharia, or "dawn shark," is known for its blade shaped teeth and bony brow.
"The teeth are very narrow side-to-side. They are blade-shaped for cutting. This animal specialized in capturing live prey and severing limbs. It was definitely a sabotage attacker, waiting for an opportunity to jump at something," Sereno said.
Eocarcharia and members of the group carcharodontosaurids gave rise to the biggest predators on southern continents, matching or exceeding Tyrannosaurus in size.
Sereno said the fossils epitomize the split world of dinosaurs during the Cretaceous period, which occurred because the continents began to drift apart.
"There is nothing quite like it in North America Cretaceous because after a few fits and starts, the tyrannosaur came into being and they are often alone as the large predatory dinosaur."