A crocodile relative that lived in what is now eastern Morocco about 165 million years ago had a jaw packed with needle-thin teeth unlike those of any other known crocodile-line animal, according to a study published Oct. 8 in the Journal of Vertebrate Paleontology.

The researchers named the animal Ctenosuchus tenuidens, drawing on Greek and Latin roots meaning comb and thin tooth. They estimate it carried more than 35 teeth on each side of its upper jaw, packed far more tightly than in any living crocodilian. The team says it likely ate small, soft prey, and it considered whether the animal strained food from the water but described that idea as tentative.

The find also adds a rare data point from Jurassic Africa, where crocodile relatives are poorly documented compared with Europe. And it raises a familiar question in paleontology — the two specimens were bought from commercial fossil collectors rather than excavated by the research team.

A Comb of Teeth Unlike Any Known Crocodylomorph

The study, led by University of Portsmouth paleontologist Hamzah Imran, describes two partial specimens from red mudstone deposits in the Talsint-Anoual area of Figuig province, according to a Sci.News summary of the paper.

Each tooth is about 10 times taller than it is wide, and neighboring teeth sit roughly 2.3 millimeters (about 0.09 inch) apart. For comparison, the living Indian gharial, a slender-snouted fish eater, has upper-jaw teeth spaced about 15 millimeters (about 0.6 inch) apart. The tooth count of more than 35 per side is an estimate based on the partial jaws, not a complete count from an intact skull.

An evolutionary analysis placed Ctenosuchus within Teleosauridae, a group of long-snouted thalattosuchians. Thalattosuchians were mostly marine crocodylomorphs that lived from the Early Jurassic to the Early Cretaceous, and some later forms evolved body plans resembling marine reptiles. The analysis found Ctenosuchus to be a close relative of Seldsienean Megistorhynchus and a group called Aeolodontini.

Freshwater Life in Jurassic North Africa

Most teleosauroids lived in coastal or marine settings. The authors say Ctenosuchus is the only freshwater teleosauroid known from Gondwana, the southern supercontinent that included Africa, and the second teleosaur species from Morocco's Jurassic rocks after an unnamed species of Machimosaurus.

That makes the find useful for understanding how these animals spread into rivers and lakes. Thalattosuchians are best documented from northwest Europe, including Germany, the United Kingdom and France, and their African record is thin. A 2016 study of Moroccan teleosauroids in Palaeontology argued that the scarcity of marine crocodylomorphs in Africa was probably a result of limited sampling rather than low original diversity.

The red beds near Talsint sit above older marine limestones and shales, part of a broad expanse of Early Jurassic to Late Cretaceous rock. That layered sequence records a shift from seawater to land-based environments in the region, which fits the authors' freshwater interpretation of the new animal.

Filter-Feeding Remains a Tentative Idea

The tightly packed teeth invite comparison with animals that strain food from water. The authors considered whether Ctenosuchus fed that way, as some Jurassic flying reptiles may have, but they presented the idea cautiously. Their main interpretation is more conservative — the animal probably ate small, soft prey such as little fish, crustaceans and soft-bodied invertebrates.

Several limits apply. The conclusions rest on two partial specimens, so the full skull shape and tooth count are reconstructed. Feeding behavior is inferred from tooth shape and spacing, not from preserved stomach contents or bite marks. No living crocodilian has a comparable dentition, which makes direct comparisons difficult. The proposed freshwater habitat comes from the rock type and locality information, which leads to the study's biggest caveat.

Fossils Bought From Commercial Collectors

The specimens did not come from a scientific excavation. "The new material was purchased from commercial fossil collectors based in Morocco," Imran and colleagues wrote, adding that the collector supplied photographs of the site and locality data.

Morocco is one of the world's major sources of commercially traded fossils, and researchers often study purchased specimens when they would otherwise be lost to private collections. The tradeoff is context. When researchers do not dig a fossil themselves, they rely on the seller's account of where and in which rock layer it was found, which is harder to verify independently. That matters here because the age estimate and the freshwater interpretation both depend on the specimens' origin.

For readers, the takeaway is to treat the filter-feeding idea as a hypothesis and the freshwater lifestyle as a well-supported but provenance-dependent conclusion. Fossil buyers, including hobbyists, can help science by asking sellers for documented locality information and by reporting scientifically unusual specimens to museums or university paleontologists.

Future discoveries of more complete jaws, ideally from documented excavations in the Talsint area, would let paleontologists confirm the tooth count and test how Ctenosuchus fed. Until then, the animal stands as a striking example of how varied crocodile relatives were during the age of dinosaurs.

The study also offers a modern echo. The Indian gharial, the living reptile the authors used for comparison, is itself a narrow-snouted river specialist whose survival depends on healthy freshwater fish populations. Ancient relatives like Ctenosuchus show that crocodile-line animals repeatedly evolved specialized jaws to exploit small prey in rivers and lakes, and that those specialists were tightly tied to the waters they lived in.

The bottom line is that Ctenosuchus tenuidens adds an unusual freshwater predator to the thin Jurassic record of North Africa. Its needle-thin teeth are well documented in the two specimens, while its exact feeding method and its environment remain interpretations that more complete, carefully excavated fossils would help confirm.

What Readers Want to Know

What is Ctenosuchus tenuidens?

It is a newly named teleosaurid thalattosuchian, a crocodile relative that lived in what is now eastern Morocco about 165 million years ago, during the Middle Jurassic.

What made its teeth unusual?

Each tooth was about 10 times taller than wide, spaced roughly 2.3 millimeters apart, with an estimated 35 or more teeth on each side of the upper jaw. Researchers say no other known crocodile relative had a similar dentition.

Did it filter-feed like a whale or flamingo?

That is unproven. The authors considered filter-feeding but called it tentative and said the animal most likely ate small, soft prey such as little fish and crustaceans.

Where were the fossils found?

The two partial specimens came from red mudstone in the Talsint-Anoual area of Figuig province. They were purchased from commercial fossil collectors, who supplied site photographs and locality data.

Why does it matter that the fossils were purchased?

Researchers did not excavate the specimens themselves, so the age and environment interpretations depend partly on the seller's locality information.

Where was the study published?

The study appeared online Oct. 8, 2026, in the Journal of Vertebrate Paleontology, led by Hamzah Imran of the University of Portsmouth.