Spinosaurus mirabilis is a large extinct species of spinosaurid theropod dinosaur known from the Late Cretaceous (Cenomanian), around 95 million years ago, discovered in the Farak Formation of Niger. It belongs to the genus Spinosaurus and was formally named in 2026 by Paul Sereno and colleagues. Like other members of its genus, it possessed a long, low snout, a scimitar‑shaped midline crest on the skull, and a large sail formed by elongated neural spines along its back.
Fossils of S. mirabilis were collected from two main localities—Iguidi and Jenguebi—during expeditions in 2000, 2019, and 2022. The holotype, MNBH JEN1, includes a fragmentary skull with premaxilla, maxillae, nasal crest, part of the dentary, and several teeth. Additional specimens from Jenguebi (JEN2–9) preserve vertebrae, limb fragments, and isolated teeth, while Iguidi material consists mostly of isolated tooth crowns and vertebral fragments. Some bones were initially misidentified as belonging to other theropods, such as Carcharodontosaurus or Sigilmassasaurus, before being reassigned to S. mirabilis in its formal description.
The species is notable for expanding the known diversity and distribution of Spinosaurus. While the better‑known S. aegyptiacus is associated with coastal deposits, S. mirabilis comes from inland fluvial environments, suggesting ecological variation within the genus. Its discovery also clarifies long‑misinterpreted vertebral material from the region and provides new anatomical details—especially regarding the skull crest—that help distinguish it from other spinosaurids. As of its description, the holotype and most specimens are housed at Abdou Moumouni University in Niger, with some Iguidi material temporarily held at the University of Chicago.
