An ancient shark graveyard has been discovered in an Egyptian desert

An Egyptian desert may have been home to a thriving underwater ecosystem and a paradise for sharks, according to researchers who have found an abundance of shark remains.

During the Cretaceous period, between about 145 to 66 million years ago, the world was warmer and had little to no polar ice. As a result, higher sea levels meant much of the land we inhabit today was underwater – this includes northern Africa.

Paleontologists unearthing parts of the Abu-Tartur Plateau – a major limestone and phosphate-rich highland in Egypt’s Western Desert between the Dakhla and Kharga oases – have discovered sharks teeth.

But not just of one shark, researchers have discovered at least seven different species.

“Collectively, this assemblage highlights a nutrient-enriched, high-productivity marine ecosystem along a phosphogenic shelf margin,” writes a team led by paleontologist Tarek Yassin of Cairo University in a paper published in Cretaceous Research.

Researchers discovered a plentiful amount of phosphorite deposits, which commonly forms in dense marine populations, and has preserved this ancient sea.

In previous research, Yassin and his colleagues identified two shark species after finding a handful of teeth in a fossil bed.

In their second search in the layers of the rock, researchers found another 14 shark teeth representing another five shark species which had not been identified at Abu-Tartur before.

The teeth were varying in size and shape, some were long and slender, others were broad.

One tooth was prominently curved and others had small, fang-like side projections, called cusplets; others did not.

“The recovered shark teeth from Egypt exhibit a variety of colours likely influenced by the condition of the phosphate ore in which they are embedded. The colours of these fossils range from black to gray and yellow, depending on the specific layer of phosphate ore they originate from,” the study authors note.

There was very little sediment accumulation during the time these sharks would have lived in these ancient waters and the phosphate bed represents a condensed span of time.

While there is no evidence that these seven shark species lived at the same time in the region, these findings do add to evidence that these ecosystems were common across the northern edge of Africa during the Late Cretaceous.