The discovery of fossils in Egypt's Western Desert has rewritten what palaeontologists know about the evolution of crocodiles.
Among the red sandstones and green shales above the arid plains of Kharga Oasis, the partial skulls and jawbones of four crocodiles have pushed back the timeline of Dyrosauridae – a group of ancient crocodiles that differed markedly from their modern relatives.
At about 80 million years old, the new fossil species, Wadisuchus kassabi, is several million years older than other finds, which is scientifically significant.
It highlights Egypt’s Western Desert as a “cradle for marine croc evolution”, Sara Saber, assistant lecturer at Assiut University, told The National. She said it shows that the species probably originated in North Africa before spreading widely.
Ohio University
Several features visible in the skull and jaws point to its place at the very base of the dyrosaurid family tree – the number of sharp fish-catching teeth, length of its snout and position of its nostrils to breathe at the surface with most of its head submerged.
These traits match a semi-marine predator lifestyle and show exactly when and how the family began to specialise for life in coastal waters, said Ms Saber. “These ancient crocs were already hunting in coastal waters long before they became dominant survivors after the dinosaurs disappeared.”
Although none of the fossils were 100 per cent complete, because four crocodiles were found the team was able to reconstruct the full anatomy. The discovery, published in The Zoological Journal of the Linnean Society, was led by a team of Egyptian palaeontologists.
Unlike today’s crocodiles, dyrosaurids thrived in coastal and marine environments, equipped with elongated snouts and slender, needle-sharp teeth ideal for seizing slippery prey such as fish and turtles. Their remarkable survival and dispersal after the extinction of the dinosaurs make them crucial for understanding how reptiles adapted and diversified when global ecosystems collapsed, the team said.
The name Wadisuchus kassabi blends Egypt’s landscape and legacy – using the Arabic terms Wadi for the New Valley, where it was discovered, and Suchus for the ancient crocodile god Sobek. The rest of the name honours Professor Ahmed Kassab of Assiut University.
The fossils were excavated near the Kharga and Baris oases in Egypt’s Western Desert and include two partial skulls and two snout tips from four individuals at different stages of growth.
Professor Hesham Sallam, Egyptian vertebrate palaeontologist at Mansoura University, and senior author of the study, said this provides “rare insight into how dyrosaurids developed”. Prof Sallam said that high-resolution CT scans and 3D surface models enabled the team to reveal “unprecedented” anatomical details.
Ms Saber, a member of the team at Mansoura’s Vertebrate Palaeontology Centre and lead author of the study, said: “Wadisuchus kassabi was a 3.5 to four-metre-long crocodile-like reptile with a very long snout and tall, sharp teeth.
"It differed from other dyrosaurids in having four teeth at the front of the snout instead of the primitive five, nostrils positioned on top of the snout for surface breathing, and a deep notch at the tip of the snout where the jaws met. These features show a gradual adaptation in the dyrosaurid bite, marking an important step in their evolutionary history.”
Ms Saber added: “The new species pushes back evidence for an African origin of Dyrosauridae and suggests that their diversification began earlier than previously thought – possibly during the Early Coniacian – Santonian about 87 to 83 million years ago, rather than the traditionally assumed Maastrichtian, about 72 to 66 million years ago.”
Another team member, Belal Salem at Ohio University, said the significance of the find “lies not only in what it reveals about the evolutionary history of this remarkable group of crocodiles – though that is a major achievement – but also in what it reminds us of: that Egypt’s Western Desert still holds treasures that preserve the secrets of our planet’s deep past.
"Our mission is not only to uncover these fossils but also to protect the fossil-rich sites from urban expansion and agricultural encroachment. They are a legacy for generations of Egyptians to come.”
