Fossils recovered from the same limestone formation used to build Egypt's Great Sphinx belong to a distinct extinct crocodilian that lived about 45 million years ago, researchers said Tuesday.
The animal, named Herugavialis cairensis, inhabited the 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 came from the Mokattam Formation, a thick limestone deposit containing fossils of fish, sharks and early whales, according to the study.
It said stone quarried 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, a nearly complete skull uncovered during the 1920s, had previously been classified as a member of Tomistoma, the genus that includes the modern false gharial of Southeast Asia.
Researchers used computed tomography, or CT, scans to examine the skull's internal anatomy and compared more than 300 features with those of living and extinct crocodilians.
Their analysis found enough differences to place the Egyptian animal in a separate genus.
The name Herugavialis combines "Heru," another name for the ancient Egyptian god Horus, with a term referring to gharials. The species name cairensis reflects its connection to Cairo.
The skull is also missing the end of its snout, an accidental resemblance to the Great Sphinx, which famously lacks 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 distinguished by their long, narrow snouts, according to the study.
Only two species survive today: the critically endangered Indian gharial and the endangered false gharial, both found in parts of South and Southeast Asia.
Their fossil record, however, shows that gharial-like crocodilians once had a much wider geographical range and that some species lived in marine environments.
The identification of Herugavialis cairensis adds to evidence that several gharial species inhabited the Mediterranean region over tens of millions of years.
Researchers said the finding provides a clearer picture of the group's complex evolutionary history.
