An international research team has identified a new genus of extinct long-snouted crocodile from 45-million-year-old fossils discovered in Egypt, according to a study published in Royal Society Open Science. The reptile, named Herugavialis cairensis, was identified through the re-examination of a historical specimen first unearthed in 1927 in the Mokattam Mountains.
The fossil was found in the Mokattam geological formation, the same limestone used by ancient Egyptians to carve the Great Sphinx. Researchers have dubbed the creature the Sphinx Crocodile because, like the famous statue, the fossil’s skull is missing the tip of its nose.
Researchers Use CT Scans to Reclassify Ancient Specimen
For decades, the specimen was scientifically classified as Tomistoma cairoensis due to its long snout and skull shape. However, subsequent evolutionary studies suggested the species was not closely related to the false gharial, prompting a modern re-evaluation. The research was led by Paul Burke of the Swedish Museum of Natural History in Stockholm and included a team from the U.K., Germany, Egypt, and Sweden.
To determine the animal’s true classification, researchers utilized CT scans to examine the internal structure of the skull and performed digital reconstructions alongside anatomical comparisons. These modern tools revealed that the snout represents approximately 64% of the total skull length and identified distinct anatomical characteristics in the eye socket and other cranial areas. These features were sufficient to establish Herugavialis as a separate genus and an early branch of the gavials—a group of crocodiles specialized for fishing.
The naming of the genus reflects its origin and lineage: Herois inspired byHeruor Horus, the ancient Egyptian deity associated with the Sphinx during the New Kingdom asHor-em-akhet; gavialisrefers to its evolutionary kinship with the modern Indian gharial; andcairensis refers to Cairo.
Climate Change Reduced Mediterranean Gavial Diversity
The fossil dates back to the Middle Eocene epoch, a period when Egypt was characterized by warm, shallow marine environments. These waters supported a variety of creatures, including sirens, whales, and long-snouted gavials. According to Burke, the Mediterranean region saw significant crocodile diversity over the last 50 million years, and this Egyptian fossil provides a critical piece of that history.
The study indicates that gavial diversity in the Mediterranean declined during the late Eocene and Oligocene, likely due to receding sea levels and a global drop in temperatures. This diversity later increased during the Miocene as sea levels and temperatures rose again.
The “Egyptian Fossils Abroad” Initiative
The specimen used in the study is currently housed in the State Museum of Natural History Stuttgart in Germany.
This work is part of a specific initiative titled Study of Egyptian Fossils Abroad,
which seeks to access and re-examine Egyptian specimens discovered decades ago. Researchers Sarah Saber and Bilal Salem noted that the evolution of imaging and analysis techniques allows scientists to ask new questions of old samples, uncovering secrets that were invisible to previous generations of paleontologists.
