Egypt’s desert was once a tropical sea filled with sharks, fossils reveal

Cairo: Fossilised shark teeth discovered in Egypt’s Western Desert have revealed that a landscape now among the driest on Earth was once covered by a warm tropical sea teeming with marine life more than 70 million years ago.

Researchers examining phosphate deposits at the Abu Tartur Plateau, between the Kharga and Dakhla oases, recovered 14 isolated teeth belonging to at least five extinct shark species. The findings were published this month in the journal Cretaceous Research.

The species, Cretalamna cf. maroccana, Scapanorhynchus cf. raphiodon, Serratolamna cf. serrata, Squalicorax bassanii and Squalicorax pristodontus, had not previously been recorded together at Abu Tartur. Two represent first records for Egypt, while Scapanorhynchus cf. raphiodon may represent its first known occurrence in Africa.

The area looked very different more than 70 million years ago. During the Late Cretaceous, much of what is now northern Africa was submerged beneath warm seas, and Abu-Tartur supported a diverse tropical marine ecosystem.

The differing shapes of the fossilised teeth also provide clues to how the sharks lived. Some were narrow and pointed, while others were broader or serrated, suggesting that the animals hunted different types of prey and occupied different ecological niches.

The sharks were part of a wider marine community that included smaller fish, invertebrates and marine reptiles. Researchers believe nutrient-rich waters may have helped sustain this ecosystem, supporting organisms at the bottom of the food chain and, in turn, larger predators.

The fossils were recovered from the Duwi Formation, a phosphate-bearing geological unit formed during the Late Cretaceous and known for preserving marine remains including shark teeth, fish bones and fragments of marine reptiles.

Over millions of years, geological and climatic changes transformed the region as the ancient seas retreated, leaving behind layers of sediment that preserved evidence of the ecosystems that once flourished there.

The researchers said the findings expand the known diversity of prehistoric sharks in North Africa and provide new evidence of the marine environments that occupied the region before the landscape evolved into the desert seen today.