Ancient crocodile species discovered in Sphinx stone material

The Moqattam Formation in northern Egypt is a thick layer of limestone that has preserved prehistoric marine fossils including fish, sharks and early whales. The same limestone rocks also served largely as the raw material for the construction by the ancient Egyptians of some of their most famous monuments, including the Great Sphinx and the pyramids at Giza.

Now scientists have identified an extinct species of crocodiles that lived millions of years before the Egyptians built these structures. Not only do the crocodile specimens have the same geological basis as the iconic landmarks, but one of the key fossils, the nearly whole skull, bears a striking resemblance to the sphinx: the skull, first discovered in the 1920s, lacks the tip of the snout like the Sphinx statue, which is known to have lost its nose. This random feature inspired researchers to name the new genus Herugavialis after Heru, or Horus, the Egyptian god associated with the creation of this mythical creature.

According to the authors of the study, published recently in the journal Royal Society Open Science, the discovery of this species expands scientists' understanding of the diversity and history of gharials, a group of crocodiles with a complex evolutionary history.

“Herugavialis cairensis is one of six gharial species that we find in the Mediterranean for 43 million years, from 66-23 million years ago. Of course, there could be even more species we just don't know about yet, said one of the study's lead authors, Paul Burke, a vertebrate paleontologist and researcher at the Swedish Museum of Natural History in Stockholm.

To date, there are only two gharial species found in the Indian subcontinent and Southeast Asia, but fossils of this species are common around the globe, with specimens found in places such as the UK, Sweden, Italy, Egypt and Japan, Burke said.

The gharials are characterized by long thin snouts, CNN notes. Two living species include the endangered Indian gharial, Gavialis gangeticus, and the endangered false gharial, Tomistoma schlegelii. The false gharial got its nickname because of its resemblance to the Indian gharial, despite being a different species.

The fossils analyzed in the new study, including the skull and five other specimens, were originally classified in 1927 as a previously named extinct species of Tomistoma cairense based on their similarity to the now-living false gharial. However, after conducting evolutionary analysis to assess the kinship of extinct and living crocodiles, as well as computed tomography or CT scans to look inside the skull, the authors of the study found that the remains do not belong to the genus Tomistoma.

Instead, the features of the crocodile represent a new genus, Herugavialis. Burke, who reconstructed the fossil garials for his doctoral project, noted the subtle differences between the unidentified species and the false garial and in December 2023 began work on an updated description.

Cherugavialis had razor-sharp teeth, “which, along with its long, thin muzzle, were adapted for fishing,” Burke said. “In the Mokattam Formation, where cherugavialis was found, fossils of several species of bony and cartilaginous fish have been preserved, which cherugavialis probably ate.”.

The eyes of the semi-aquatic predator also had to protrude from the skull, like the Indian gharial, because the sockets were raised like a spyglass, Burke added.

The skull of Herugavialis may not have been found inside the Great Sphinx itself, but the statue and pyramids are known to be treasures of both ancient Egyptian and prehistoric finds. Previously, scientists have discovered hundreds of thousands of smaller fossilized organisms, such as bivalve mollusks and foraminiferas — tiny creatures that once inhabited Egypt’s marine ecosystem — that have been found in majestic monuments.