Scientists named a new 95-million-year-old Spinosaurus that fished the rivers of what is now Niger

Paleontologists working in the rock formations of the central Sahara have described a new predatory dinosaur belonging to the spinosaurs, a family of long-snouted hunters that lived close to water. The animal roamed a landscape that is now arid desert but was, in the mid-Cretaceous, a green world of rivers, channels and floodplains full of fish. The find extends the known range of a group whose semi-aquatic habits have made it one of the most argued-over branches of the dinosaur family tree.

A predator shaped for river margins

Spinosaurs stand apart from other large meat-eating dinosaurs. Instead of the deep, blade-toothed skull of a tyrannosaur, they carried long, narrow jaws lined with cone-shaped teeth, closer in form to a crocodile than to a typical land carnivore. Some species also bore a tall sail or ridge of bone running along the back. Together those features point to a life spent stalking the edges of rivers and lakes rather than pursuing prey across open ground.

The newly described animal fits that pattern. Its assignment to the spinosaur family rests on anatomical traits shared with better-known relatives, adding another member to a lineage that appears to have specialized in seizing slippery, fast-moving fish from shallow water.

The green Sahara of the mid-Cretaceous

The desert that now stretches across much of the region looked nothing like this when the dinosaur was alive. Braided rivers cut across broad plains, and seasonal floods spread nutrients that fed abundant plant and animal life. Large fish, including lungfish and the deep-bodied relatives of today’s coelacanths, shared the waterways with crocodile-like reptiles and turtles.

For a predator with a fish-heavy diet, that setting offered a dependable food supply within easy reach. The tight link between spinosaur anatomy and these ancient wetlands is a large part of why researchers keep returning to the region’s exposed rock, layer after layer of it recording a vanished aquatic world.

Reading a fossil more than 95 million years old

The remains have been dated to more than 95 million years old, placing the animal in the middle of the Cretaceous period, tens of millions of years before the mass extinction that ended the age of dinosaurs. Rock of that age is difficult to work: fossils are often fragmentary, scattered by ancient currents and further broken by erosion over the long span since.

Even incomplete material can be diagnostic, however. Distinctive features of the jaws, teeth and vertebrae allow paleontologists to distinguish one spinosaur from another and to slot a new specimen into the wider family. That painstaking comparison is how a scatter of bones becomes a named species with a defined place in evolutionary history.

What sets the new species apart

No two spinosaurs are identical, and the differences matter. Variations in snout shape, tooth spacing and the structure of the back reveal how individual species adapted to slightly different niches along the same waterways. Some may have taken larger prey, others concentrated on smaller fish, reducing direct competition among predators sharing one crowded ecosystem.

By identifying the new animal as a separate species, the researchers signal that the diversity of these river hunters was greater than a single famous form suggests. Each addition sharpens the picture of a family that spread widely and split into multiple lineages across what were then the southern continents.

Why spinosaurs still spark debate

Few dinosaur groups generate as much scientific disagreement. Researchers continue to argue over how deeply spinosaurs entered the water: whether they actively swam and dived after prey, propelled by a tall, paddle-like tail, or whether they mostly waded and snatched fish from the surface like an oversized heron. Studies of their bone density and body proportions have been marshaled on both sides.

New specimens are the only way to settle such questions. Every well-preserved skeleton adds evidence about how these animals moved, fed and lived, and a fresh species from the Cretaceous rivers of the Sahara gives specialists another data point in a debate that has run for years and shows no sign of closing.

Piecing together a lost ecosystem

A single predator is only part of a much larger story. The rock that yielded the new spinosaur also preserves traces of the plants, fish and other animals that shared its world, and paleontologists read those clues together to reconstruct an entire ancient community. The fish that filled the rivers, the crocodile relatives that patrolled them and the vegetation along the banks all set the stage on which the dinosaur lived and hunted.

Understanding that setting helps explain why an animal shaped for fishing thrived where it did. A predator so dependent on rivers could only exist in a landscape that kept those rivers full, and the mid-Cretaceous Sahara did exactly that for millions of years. When the climate and geography later shifted, the wetlands vanished and the specialized hunters that relied on them disappeared with them.

Each fossil recovered from these beds adds a piece to that vanished picture. The new species is valuable not only in isolation but as one more thread in a record that, slowly and carefully, reveals what an entire river world looked like nearly a hundred million years ago.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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