Full Breakdown
New Gavial Species Unearthed from the Same Limestone as Egypt’s Great Sphinx
By Drooid · · How we work
Core Discovery
Researchers re-examined a nearly complete crocodilian skull from the 45-million-year-old Mokattam Formation in northern Egypt and identified a new genus and species, Herugavialis cairensis. 3-D X-ray imaging and phylogenetic analysis showed it does not belong to the living false gharial genus *Tomistoma*. The findings were published in *Royal Society Open Science* on October 7.
Background & Context
The Mokattam Formation supplied the limestone quarried for the Great Sphinx and nearby pyramids. Fossils from this formation were first described in the 1920s as *Tomistoma cairense*. Modern CT scanning now reveals internal braincase and nasal-cavity structures that justify a new taxonomic placement. An international team from the United Kingdom, Sweden, Germany and Egypt conducted the study, led by Paul Burke (Swedish Museum of Natural History, Stockholm).
Key Findings
- Morphology: The skull has a long, slender snout, razor-sharp teeth and telescopic eye sockets; the snout tip is missing, echoing the Sphinx’s absent nose.
- Ecology: The animal was a coastal predator adapted to shallow marine environments of the middle Eocene Tethys Sea.
- Phylogeny: Analyses place *Herugavialis* on an early branch of the gavial lineage, distinct from other African and Mediterranean gavial-type crocodilians.
Data & Statistics
- Age of host rocks: ~45 Ma (middle Eocene).
- Specimens examined: one near-complete skull plus five additional fossil elements.
- Known Mediterranean gavial diversity: six species documented over a 43-million-year interval (66–23 Ma).
- Modern gavial representation: two extant species (*Gavialis gangeticus* and *Tomistoma schlegelii*) in South-Asian freshwater habitats.
Official Statements & Responses
- Paul Burke emphasized that modern methodologies enabled precise identification of the fossil and noted the abundance of other marine species in the same formation.
- Philip Mannion highlighted the likelihood of additional fossils remaining within the stone used for the Sphinx, suggesting continued discovery potential.
- Khalafallah Salih (Al Neelain University) argued that the find complicates the previously understood evolutionary history of African gavials, indicating an early split from other lineages.
- Burke also reminded the public that living gavials are critically endangered, underscoring the relevance of understanding their deep evolutionary past.
Verbatim Quotes
- “As we’ve advanced in the last 100 years, we’ve got so many new methodologies we could implement to figure out what kind of species this fossil is,” — Paul Burke
- “It’s probable that larger fossils are also present within the walls of these monuments and I think it’s very likely that other fossils will continue to be found in this formation, especially of animals that like shallow marine environments,” — Philip Mannion
Why It Matters
The reclassification expands the known diversity of ancient gavialids and clarifies crocodilian evolution in the Tethys-era Mediterranean. Linking a newly described species to the limestone that formed the Great Sphinx shows how revisiting historic collections can reveal past ecosystems. The research also connects past sea-level changes to crocodile diversification, offering analogues for modern biodiversity loss among remaining gharial species.
What’s Next
The authors will apply the same CT-based workflow to other poorly understood specimens from the Mokattam Formation and comparable Eocene deposits across the Mediterranean, aiming to uncover additional crocodilian taxa and refine timelines for marine-to-freshwater transitions within the gavial lineage.