Extinct crocodilian discovered in limestone used to build the Great Sphinx

Fossils from the limestone formation used to build Egypt’s Great Sphinx belong to a previously unidentified extinct crocodilian that lived about 45 million years ago, researchers said.

The species, named Herugavialis cairensis, inhabited a shallow tropical sea that once covered what is now northern Egypt, according to a study published in the journal Royal Society Open Science.

Its remains were found in the Mokattam Formation, a thick limestone deposit containing fossils of fish, sharks and early whales. Stone from the formation was later used in some of ancient Egypt’s best-known monuments, including the Great Sphinx and the Giza pyramids.

The key specimen is a nearly complete skull discovered in the 1920s. It had previously been classified as belonging to Tomistoma, the genus that includes the modern false gharial of Southeast Asia.

Researchers used CT scans to examine the skull’s internal anatomy and compared more than 300 features with those of living and extinct crocodilians. Their analysis revealed enough differences to classify the Egyptian animal as a separate genus.

The genus name combines “Heru,” another name for the ancient Egyptian god Horus, with a term referring to gharials. The species name, cairensis, refers to its connection to Cairo.

The skull is missing the tip of its snout, an accidental resemblance to the Great Sphinx, which is famously missing its nose. “Given this coincidence with the famously missing nose of the Great Sphinx, we decided to name the new crocodile after the Egyptian god Heru, who was possibly the inspiration for this iconic monument,” said study co-leader Philip Mannion of University College London.

Gharials are crocodilians with long, narrow snouts. Only two species survive today: the critically endangered Indian gharial and the endangered false gharial, both found in parts of South and Southeast Asia.

Fossils show that gharial-like crocodilians once ranged much more widely and that some species lived in marine environments. Researchers said the identification of Herugavialis cairensis adds to evidence that several gharial species inhabited the Mediterranean region over tens of millions of years and offers a clearer picture of the group’s complex evolutionary history.