Ctenosuchus tenuidens identified as ancient crocodile relative
- A 170-million-year-old crocodile relative unearthed in the Atlas Mountains of southeastern Morocco possessed needle-thin, comb-like teeth designed for capturing tiny aquatic prey rather than large animals.
- The fossils originated in rocks formed within ancient rivers and lakes across Gondwana, the southern supercontinent that encompassed modern-day Africa.
- We carefully scratched around one of the black circles with a scalpel, and as we uncovered more of it, it became longer and longer.
A 170-million-year-old crocodile relative unearthed in the Atlas Mountains of southeastern Morocco possessed needle-thin, comb-like teeth designed for capturing tiny aquatic prey rather than large animals. Researchers from the University of Portsmouth and Hassan II University of Casablanca identified the new species, named Ctenosuchus tenuidens, in a study published on October 8, 2026, in the Journal of Vertebrate Paleontology.
Fossil Discovery in the Atlas Mountains
The fossils originated in rocks formed within ancient rivers and lakes across Gondwana, the southern supercontinent that encompassed modern-day Africa. Ctenosuchus tenuidens belonged to thalattosuchians, a group of marine and freshwater reptiles that lived during the age of the dinosaurs. Identifying the unusual dentition required meticulous laboratory work involving microscopes and scalpels. Lead author Hamzah Imran, from the University of Portsmouth’s School of the Environment and Life Sciences, described spotting small black circles on either side of a central long bone in the fossil.
We carefully scratched around one of the black circles with a scalpel, and as we uncovered more of it, it became longer and longer. That’s when we realized these little black circles were actually incredibly thin teeth,
Imran stated regarding the extraction process.
Delicate Dentition and Soft-Prey Diet
Microscopic examination revealed that the teeth featured specialized ridges and a closely spaced arrangement. Because the teeth are exceptionally fine and fragile, the researchers concluded that the animal hunted small, soft creatures rather than typical vertebrate prey. According to the study, normal struggling prey would easily shatter the delicate dental structures.
The teeth are so fine that we don’t think it was catching normal prey. If it caught a big fish, and the fish wriggled, those delicate teeth would get smashed. We think the animal was probably eating soft prey like shrimp, worms and tiny fish, so nothing that would break its teeth.Hamzah Imran
These feeding adaptations separate Ctenosuchus tenuidens from other long-snouted crocodiles. The species’ comb-like teeth share functional similarities with ancient aquatic reptiles called mesosaurs and certain Jurassic pterosaurs, such as Gnathosaurus and Ctenochasma. Scientists believe those pterosaurs also operated as filter feeders, separating tiny food items from water.
Evolutionary Parallels Across Prehistoric Lineages
The morphological overlap between Ctenosuchus and pterosaur groups demonstrates that different reptile lineages independently evolved comparable tools for catching minute aquatic organisms. The discovery broadens scientific understanding of Jurassic ecosystems in Gondwana and highlights the diverse ecological roles filled by thalattosuchian reptiles in ancient freshwater habitats. The study describing the find, titled A new teleosauroid (Crocodylomorpha, Thalattosuchia) with a unique dentition from the Middle Jurassic of eastern Morocco,
is available via the Journal of Vertebrate Paleontology.