Palaeontologists announced a new dinosaur species, Spinosaurus mirabilis, based on fossils recovered from a remote part of Niger's Sahara Desert. The animal lived about 95 million years ago and was estimated to have been roughly the size of Tyrannosaurus rex. The findings were published in the journal Science.
The new spinosaur had interlocking rows of teeth suited to catching slippery fish and a large, scimitar-shaped crest that researchers believe was covered in keratin and may have been brightly coloured. Expedition leader Paul Sereno, a professor at the University of Chicago, envisioned it wading on strong legs in water as deep as two metres while spending much of its time hunting fish in shallower areas.
The search began with a brief entry in a French geologist's monograph from the 1960s describing a dinosaur tooth at a site in Niger. The entry included neither photographs nor other supporting material, and no one had returned to the location for more than 70 years. Sereno's team tried to reach it in 2018 but turned back within 50 miles because a sand sea blocked the route.
Researchers returned in 2019 and found the original site with drones and GPS. It produced fossils, though not the larger specimens they wanted. A local Tuareg man then led the group toward another location, reached after about a day and a half of travel. The team recovered a Spinosaurus tooth, part of a jaw and an unusual piece of bone later recognised as belonging near the base of a crest.
The pandemic and the cost of a larger expedition delayed a follow-up. In 2022, Sereno returned with an international group of 20 researchers and 64 armed guards travelling in four vehicles. The expedition collected 55 tons of material. On the first day back at the fossil area, Daniel Vidal, a University of Chicago postdoctoral researcher, found another crest section attached to more of the skull. Its form convinced the team that the bones belonged to a previously unknown species.
The crest was particularly important because, without it, differences in the other fossils might have been interpreted as variation within an existing species. Sereno said the inland setting also supported his view that spinosaurs were not marine divers. Their air-filled, bird-like skeletons and relatively stiff bodies and tails, he argued, were poorly adapted for long-distance ocean movement.
The Niger discovery may also help researchers examine how spinosaurs were distributed between North Africa and Brazil. The new material provides anatomical evidence from a region that could clarify how the group moved across ancient connected landscapes.
