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Instead, Carcharodontosaurus closely resembles certain North American carnivores. This implies that the species were exchanging genes well into the early Cretaceous period, which ended perhaps 100 million years ago. Did a bridge of land connect Laurasia and Gondwana after the rest of the landmasses had mostly separated? That's what the new evidence suggests. By 90 million years ago, the separation of continents was evidently complete; Deltadromeus and other African dinosaurs from that period are quite distinct.
Finally, while size records aren't supposed to be high on paleontologists' agenda, the immensity of C. saharicus does bear on dinosaur evolution, especially when it's put into context. Last fall paleontologists working in South America found a similarly huge carnivore, called Giganotosaurus, that was said to be a little larger than T. rex (in fact, the sizes of all three giants probably overlapped). "What's interesting," observes Norell, "is that everywhere you go in the world you have these truly enormous carnivorous dinosaurs that were much larger than any terrestrial carnivores since." One implication, says Sereno: "I think we're looking at the Olympic-size limit for this sort of animal. It's telling us that this is the largest they could grow and still survive." Or at least, that's where the evidence points today. Given that Africa's dinosaurs are just now coming to light, it's too early to draw conclusions. An even bigger predator could be lurking under the Moroccan sandstone, just waiting for the next field season.
--With reporting by Andrea Dorfman/New York