# Spinosauridae
**Spinosauridae** is a family of large, fish-eating theropod dinosaurs characterized by a long, narrow skull, robust forelimbs bearing a hooked thumb claw, and tall neural spines on the back vertebrae that formed a dorsal sail. Their piercing, conical teeth and elongated, crocodilian-like snouts indicate a diet centered on fish, and their ecology has been debated since the original discovery of *Spinosaurus aegyptiacus* in 1912.[1](https://www.sciencedirect.com/science/article/pii/S0195667117303427)
| Key fact | Detail |
|---|---|
| Defining anatomy | Long, narrow skull; robust forelimbs with a hooked thumb claw; tall neural spines forming a dorsal sail[1](https://www.sciencedirect.com/science/article/pii/S0195667117303427) |
| Diet | Piscivorous, inferred from piercing teeth and skull and jaw morphology resembling piscivorous crocodilians[1](https://www.sciencedirect.com/science/article/pii/S0195667117303427) |
| First named member | *Spinosaurus aegyptiacus*, named by Ernst Stromer in 1915 from material collected in 1912 at the Bahariya Oasis, Egypt, with neural spines up to 165 cm tall[2](https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0187070) |
| Fossil record | Body fossils are generally rare; most species are known from limited skeletal remains, and isolated teeth are the most common identifiable finds[3](https://doi.org/10.1111/1755-6724.13328) |
| Distribution | Europe (UK, France, Portugal, Spain), Africa, Brazil, and Asia (Laos, Thailand, China)[3](https://doi.org/10.1111/1755-6724.13328) • [4](https://www.livescience.com/animals/dinosaurs/spinosaurus-relative-longer-than-a-pickup-truck-stalked-thailands-rivers-125-million-years-ago) |
| Lifestyle debate | Semiaquatic wading ambush predator is the current majority view; a fully aquatic pursuit-predator hypothesis has been advanced and contested[5](https://doi.org/10.7554/eLife.80092) • [6](https://palaeo-electronica.org/content/2021/3219-the-ecology-of-spinosaurus) |
## Anatomy and feeding
The spinosaurid skull is long and low, with a narrow snout and a distinctive notch near the front of the jaws, a shape convergent on that of piscivorous crocodilians.[1](https://www.sciencedirect.com/science/article/pii/S0195667117303427) • [7](https://www.nhm.ac.uk/discover/dino-directory/spinosaurus.html) The teeth are more or less conical and unserrated, suited to piercing rather than slicing, and in *Spinosaurus* the lower-jaw teeth protrude outward and interlock with the upper teeth, a fish-trapping arrangement.[8](https://igg.cas.cn/sourcedb_igg_cas/cn/zjrck/200907/W020120622356922971023.pdf) • [9](https://www.livescience.com/animals/dinosaurs/95-million-year-old-spinosaurus-had-a-scimitar-shaped-head-crest-and-waded-through-the-saharas-rivers-like-a-hell-heron) The forelimbs were robust, with a hooked thumb claw, and the dorsal vertebrae carried extremely tall neural spines that supported a sail; in the type specimen of *Spinosaurus* these spines reached up to 165 cm in height.[1](https://www.sciencedirect.com/science/article/pii/S0195667117303427) • [2](https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0187070)
Direct dietary evidence exists for at least one member: possibly acid-etched lepidotid fish scales were found in the ribcage of *Baryonyx walkeri*, and pterosaur remains have also been reported as part of a spinosaur diet.[10](https://www.sciencedirect.com/science/article/pii/S019566712030313X) • [3](https://doi.org/10.1111/1755-6724.13328)
## Discovery history
The family was erected for *Spinosaurus aegyptiacus*, from the Cenomanian of Egypt.[8](https://igg.cas.cn/sourcedb_igg_cas/cn/zjrck/200907/W020120622356922971023.pdf) The fossil collector Richard Markgraf unearthed a partial skeleton with neural spines up to 165 cm tall at the Bahariya Oasis in western Egypt in 1912, and the paleontologist Ernst Stromer named the animal in 1915.[2](https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0187070) • [11](https://www.nhm.ac.uk/discover/how-did-baryonyx-change-what-we-knew-about-spinosaurs.html) The original fossils went on display in Munich and were destroyed by Allied bombing during the Second World War, leaving only Stromer's drawings and descriptions; for decades afterward spinosaurid material was largely restricted to isolated bones and teeth, many of which had been misidentified as crocodylomorph remains.[11](https://www.nhm.ac.uk/discover/how-did-baryonyx-change-what-we-knew-about-spinosaurs.html) • [2](https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0187070)
**Baryonyx changed the picture.** Between May and June 1983, paleontologists in England excavated a reasonably complete animal determined to be a new species, *Baryonyx walkeri*, named in 1986. Its fish-eating skull and teeth gave the first detailed insight into spinosaur anatomy and confirmed the group's piscivory.[11](https://www.nhm.ac.uk/discover/how-did-baryonyx-change-what-we-knew-about-spinosaurs.html) • [12](https://www.nhm.ac.uk/discover/what-is-a-fossil.html) A flurry of discoveries and taxonomic revisions followed, including *Suchomimus* from Niger and *Ichthyovenator* from Laos, the first definitive Asian spinosaurid.[13](https://www.nhm.ac.uk/discover/news/2026/february/new-sabre-crested-spinosaurus-species-named-from-desert-dinosaur-fossils.html) • [3](https://doi.org/10.1111/1755-6724.13328) In 2014 a newly discovered *Spinosaurus aegyptiacus* skeleton from Morocco was designated the neotype, the new type specimen for the species.[13](https://www.nhm.ac.uk/discover/news/2026/february/new-sabre-crested-spinosaurus-species-named-from-desert-dinosaur-fossils.html)
## Distribution and diversity
Spinosaurid fossils have been recovered extensively in Europe, including the UK, France, Portugal, and Spain, as well as across North Africa and Brazil; the extensively sampled Jurassic and [Cretaceous](https://www.edgepedia.org/cretaceous) beds of North America have so far yielded no definitive spinosaurid evidence.[3](https://doi.org/10.1111/1755-6724.13328) Asian records include China, Laos, and Thailand, where a specimen nicknamed the Sam Ran spinosaurid, roughly 25 feet (7 to 8 meters) long and about 125 million years old, represents one of the most complete spinosaurid specimens ever found in Asia.[4](https://www.livescience.com/animals/dinosaurs/spinosaurus-relative-longer-than-a-pickup-truck-stalked-thailands-rivers-125-million-years-ago) The Lower Cretaceous Iberian record alone includes five described spinosaurid genera and species, making Spinosauridae the most prevalent theropod group there.[14](https://www.sciencedirect.com/science/article/pii/S0195667125000576)
Where the family originated is unresolved. Fossil evidence suggests a possible origin in Laurasia (western Europe), but the existence of a tooth older than the European taxa might indicate an origin in Gondwana (Brazil).[15](https://sbpbrasil.org/publications/index.php/paleodest/article/view/357/) Spinosaurids appear to have shared their habitats with other large predators, including abelisaurids and carcharodontosaurids, and even with other spinosaurids where conditions allowed.[15](https://sbpbrasil.org/publications/index.php/paleodest/article/view/357/)
## Ecology and the aquatic debate
Several independent lines of evidence point to a close association with water. An oxygen isotope analysis of tooth enamel compared spinosaurid phosphatic remains with those of coexisting terrestrial theropods and semiaquatic crocodilians and turtles, concluding that spinosaurids spent a large part of their daily time in water, like extant crocodilians or hippopotamuses.[8](https://igg.cas.cn/sourcedb_igg_cas/cn/zjrck/200907/W020120622356922971023.pdf) Spinosaurids are abundant in fluvial and nearshore marine deposits, where they occur alongside a rich freshwater fish fauna including sharks, lungfish, and coelacanths, which they most likely fed on.[1](https://www.sciencedirect.com/science/article/pii/S0195667117303427) A 2022 ecomorphological analysis in *Nature* recovered Spinosauridae as adapted to life in water, an adaptation otherwise absent among the non-avian dinosaurs studied.[16](https://www.nature.com/articles/s41586-022-04528-0)
**The strongest claims have been contested.** A 2014 study proposed that *Spinosaurus* was the first known semiaquatic non-avian dinosaur, citing retracted nostrils, an elongated neck and trunk shifting the center of body mass forward, and hind limb bones infilled to serve as ballast.[17](https://www.researchgate.net/profile/David-Martill/publication/265553416_Semiaquatic_adaptations_in_a_giant_predatory_dinosaur/links/545361430cf2bccc4909c198/Semiaquatic-adaptations-in-a-giant-predatory-dinosaur.pdf) A 2022 re-analysis using CT scans found major discrepancies with that skeletal reconstruction and concluded that *Spinosaurus* was not an aquatic dinosaur: the infilled hind limb bones more likely served weight support on land, and the animal is better envisioned as a bipedal, semiaquatic ambush predator of large fish, wading into shallow coastal and riverine waters.[5](https://doi.org/10.7554/eLife.80092) A 2021 review reached a similar conclusion, finding the evidence for specialized aquatic [pursuit predation](https://www.edgepedia.org/pursuit-predation) unsupported while noting that *Spinosaurus* almost certainly fed primarily from the water and may have swum, and that alternative interpretations for the sail, such as socio-sexual signaling, are supported.[6](https://palaeo-electronica.org/content/2021/3219-the-ecology-of-spinosaurus) A later methodological review likewise concluded that the best current evidence supports *Spinosaurus* as a semiaquatic piscivore but not an aquatic pursuit predator.[18](https://pmc.ncbi.nlm.nih.gov/articles/PMC10917332/)
## Recent discoveries
In February 2026, a team led by Paul Sereno, a paleontologist at the University of Chicago, named *Spinosaurus mirabilis* from a nearly complete skeleton found in a river deposit in Niger, far from any coastline. The species carries a curved, blade-like head crest that would have stood up to 20 inches (0.5 meters) tall in life, the tallest crest known in any meat-eating dinosaur, and the authors interpret it as decorative, possibly for identifying mates or rivals. Based on the inland river-bed burial and body shape, the team places the animal between semiaquatic waders like herons and aquatic divers like penguins, describing it as a "hell heron" that waded on sturdy legs into water up to two meters (6.5 feet) deep while stalking large fish.[9](https://www.livescience.com/animals/dinosaurs/95-million-year-old-spinosaurus-had-a-scimitar-shaped-head-crest-and-waded-through-the-saharas-rivers-like-a-hell-heron) • [19](https://biologicalsciences.uchicago.edu/news/new-scimitar-crested-spinosaurus-species-discovered-central-sahara)
## References
1. [Aquatic adaptation in the skull of carnivorous dinosaurs (Theropoda: Spinosauridae) and the evolution of aquatic habits in spinosaurids, Cretaceous Research](https://www.sciencedirect.com/science/article/pii/S0195667117303427)
2. [Spinosaur taxonomy and evolution of craniodental features: Evidence from Brazil, PLOS One](https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0187070)
3. [Hone, D.W.E. and Holtz, T.R. Jr (2017). A Century of Spinosaurs - A Review and Revision of the Spinosauridae with Comments on Their Ecology. Acta Geologica Sinica 91: 1120-1132](https://doi.org/10.1111/1755-6724.13328)
4. [Spinosaurus relative longer than a pickup truck stalked Thailand's rivers 125 million years ago, Live Science](https://www.livescience.com/animals/dinosaurs/spinosaurus-relative-longer-than-a-pickup-truck-stalked-thailands-rivers-125-million-years-ago)
5. [Spinosaurus is not an aquatic dinosaur, eLife](https://doi.org/10.7554/eLife.80092)
6. [The ecology of Spinosaurus, Palaeontologia Electronica](https://palaeo-electronica.org/content/2021/3219-the-ecology-of-spinosaurus)
7. [Spinosaurus, Natural History Museum Dino Directory](https://www.nhm.ac.uk/discover/dino-directory/spinosaurus.html)
8. [Amiot, R. et al. Oxygen isotope evidence for semi-aquatic habits among spinosaurid theropods, Geology](https://igg.cas.cn/sourcedb_igg_cas/cn/zjrck/200907/W020120622356922971023.pdf)
9. [95 million-year-old Spinosaurus had a scimitar-shaped head crest and waded through the Sahara's rivers like a 'hell heron', Live Science](https://www.livescience.com/animals/dinosaurs/95-million-year-old-spinosaurus-had-a-scimitar-shaped-head-crest-and-waded-through-the-saharas-rivers-like-a-hell-heron)
10. [Taphonomic evidence supports an aquatic lifestyle for Spinosaurus, Cretaceous Research](https://www.sciencedirect.com/science/article/pii/S019566712030313X)
11. [How did Baryonyx change what we knew about spinosaurs? Natural History Museum](https://www.nhm.ac.uk/discover/how-did-baryonyx-change-what-we-knew-about-spinosaurs.html)
12. [What is a fossil? Natural History Museum](https://www.nhm.ac.uk/discover/what-is-a-fossil.html)
13. [New sabre-crested Spinosaurus species named from desert dinosaur fossils, Natural History Museum](https://www.nhm.ac.uk/discover/news/2026/february/new-sabre-crested-spinosaurus-species-named-from-desert-dinosaur-fossils.html)
14. [A giant spinosaurid from the Iberian Peninsula and new data on the Early Cretaceous Iberian non-avian theropod palaeodiversity, Cretaceous Research](https://www.sciencedirect.com/science/article/pii/S0195667125000576)
15. [Família Spinosauridae (Dinosauria: Theropoda): taxonomia, paleobiogeografia e paleoecologia (uma revisão), Paleontologia em Destaque](https://sbpbrasil.org/publications/index.php/paleodest/article/view/357/)
16. [Subaqueous foraging among carnivorous dinosaurs, Nature](https://www.nature.com/articles/s41586-022-04528-0)
17. [Ibrahim, N. et al. (2014). Semiaquatic adaptations in a giant predatory dinosaur, Science 345: 1613-1616](https://www.researchgate.net/profile/David-Martill/publication/265553416_Semiaquatic_adaptations_in_a_giant_predatory_dinosaur/links/545361430cf2bccc4909c198/Semiaquatic-adaptations-in-a-giant-predatory-dinosaur.pdf)
18. [Diving dinosaurs? Caveats on the use of bone compactness and pFDA for inferring lifestyle, PMC](https://pmc.ncbi.nlm.nih.gov/articles/PMC10917332/)
19. [New 'scimitar-crested' Spinosaurus species discovered in the central Sahara, University of Chicago Biological Sciences](https://biologicalsciences.uchicago.edu/news/new-scimitar-crested-spinosaurus-species-discovered-central-sahara)
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