Spinosaurus mirabilis

Spinosaurus mirabilis was formally described in 2026 from Cenomanian rocks of the central Sahara in Niger. Its most striking feature is a tall nasal-prefrontal crest that curves backward like a scimitar and bears vascular grooves, suggesting that a keratin covering may have enlarged it in life. The fossils were recovered from riparian deposits alongside long-necked dinosaurs. In the describing analysis it is the sister species of Spinosaurus aegyptiacus, but its known sample consists only of immature individuals and much of the adult skeleton remains unknown.

Its fossils occur between approximately 100.5 and 93.9 million years ago. Values shown here are approximate and reflect the current curated seed dataset.

The holotype is a subadult represented mainly by a fragmentary skull and teeth. Referred specimens add isolated cranial and postcranial bones, including vertebral and foot material. Reconstructions therefore combine directly preserved anatomy, traits shared with S. aegyptiacus and explicitly labelled inference; the adult proportions, mass and final crest size cannot yet be measured.

• Tall, backward-curving scimitar-shaped nasal-prefrontal crest
• Vascular grooves on the crest, consistent with a keratinous covering
• Low, parallel-sided snout with an expanded tip
• Conical teeth suited to gripping rather than slicing
• Widely spaced rear maxillary teeth
• Tall vertebral spines inferred to have supported a dorsal sail
• Possible proportionally longer hind limbs than in S. aegyptiacus

Paul Sereno-led teams excavated material at Iguidi and Jenguebi in Niger during field seasons in 2000, 2019 and 2022. The holotype, MNBH JEN1 from Jenguebi, includes parts of the snout and lower jaw, the diagnostic crest and teeth. Sereno and 28 coauthors named the species on 19 February 2026. The name mirabilis means 'astonishing' and refers to the enlarged nasal-prefrontal crest.

Discovery credit: Paul C. Sereno-led field teams.

Naming authors: Paul C. Sereno, Daniel Vidal, Nathan P. Myhrvold and 26 coauthors.

The Jenguebi fossils came from the Farak Formation, interpreted as a river-margin or riparian setting in the central Sahara. The describing paper reports S. mirabilis living alongside long-necked dinosaurs. Referred Iguidi material comes from Cenomanian deposits of the Echkar Formation.

The authors interpreted derived spinosaurines as large, shallow-water ambush specialists. The crest was probably a visual display structure, but sex, colour and exact function cannot be recovered from the fossils. No direct evidence establishes its social behaviour, swimming performance or complete diet.

• The species was announced in 2026, more than a century after S. aegyptiacus was named.
• Its diagnostic crest rises from the skull roof and curves backward like a scimitar.
• Every individual currently recognised is immature, so its maximum adult size is unknown.
• The holotype is catalogued as MNBH JEN1 and is held in Niger.

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1. 01
   The Paleobiology Database

   Open source
2. 02
   Spinosaurus is not an aquatic dinosaur

   Paul C. Sereno, Nathan P. Myhrvold, Donald M. Henderson, Frank E. Fish · eLife · 2022

   Open source
3. 03
   Scimitar-crested Spinosaurus species from the Sahara caps stepwise spinosaurid radiation

   Paul C. Sereno, Daniel Vidal, Nathan P. Myhrvold and 3 coauthors · Science · 2026

   Open source
4. 04
   PubMed record: Scimitar-crested Spinosaurus species from the Sahara caps stepwise spinosaurid radiation

   U.S. National Library of Medicine · 2026

   Open source