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Fossilized teeth from at least seven shark species have been discovered in the Egyptian desert, hinting at its complex, watery past.

The desert sands of Egypt have been dry for thousands of years. As difficult as it is to picture now, however, much of that desert was once submerged beneath a sea that covered much of the northern perimeter of the African continent. Nor was it a dead sea – evidence suggests that, during the Cretaceous period, it may have been a tropical wonderland, where rising currents lifted nutrients into the water column to feed a thriving ecosystem. Now, buried in what was once the floor of that long-ago sea, on the Abu-Tartur Plateau, paleontologists have found evidence of its lushness: the teeth of sharks that would have thrived amid the bounty of fish. And not just one shark. The total number of different species found in that layer of the Duwi Formation now numbers at least seven – offering a glimpse of the rich marine ecosystems that once flourished along the northern edge of Africa. The 14 teeth represented five species. (Yassin et al., Cretac.