Spinosaurus aegyptiacus

Spinosaurus aegyptiacus lived in northern Africa during the Cenomanian age of the Late Cretaceous. It is one of the largest known predatory dinosaurs, but no complete skeleton is known and its proportions have repeatedly changed as new material has been described. The animal combined a long, fish-catching skull with powerful forelimbs, an immense dorsal sail and an unusually deep tail. These features clearly connect it with waterside habitats, although researchers disagree over whether it pursued prey underwater or foraged mainly in shallow water and along shorelines.

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 reconstruction is a composite scientific hypothesis. The Egyptian holotype preserves parts of the skull, vertebral column and ribs; Moroccan material supplies much of the limb, pelvic and tail anatomy used in modern restorations. Because the association and identity of some Moroccan bones have been challenged, the exact body plan is less certain than the familiar silhouette suggests.

• Long, low skull with a widened, rosette-like snout
• Straight to slightly curved conical teeth with little or no serration
• Extremely tall dorsal neural spines forming a sail or ridge
• Robust forelimbs with a large claw on the first finger
• Reduced pelvis and relatively short hind limbs in modern reconstructions
• Deep, flexible tail with elongated spines and chevrons
• Dense limb bones reported as a possible adaptation to life around water

Richard Markgraf found the first confidently referable skeleton in Egypt's Bahariya Oasis in 1912. Ernst Stromer named Spinosaurus aegyptiacus in 1915 from holotype BSP 1912 VIII 19. The fossils were kept in Munich and destroyed during an Allied bombing raid on 24–25 April 1944; Stromer's published plates, notes and surviving photographs are therefore crucial evidence. A partial Moroccan skeleton, FSAC-KK-11888, was described in 2014 after its locality was relocated. It was proposed as a neotype, but both that designation and the specimen's taxonomic assignment have been disputed.

Discovery credit: Richard Markgraf.

Naming authors: Ernst Stromer.

Known from river-dominated environments in what are now Egypt and Morocco. These Cenomanian systems supported abundant fish, crocodyliforms, turtles, pterosaurs and several large theropods. The Moroccan material assigned to this species comes from the Kem Kem Group; the holotype came from the Bahariya Formation.

Its snout and teeth are well suited to seizing slippery prey, and direct evidence from related spinosaurs confirms that fish formed part of the family's diet. Spinosaurus probably also took terrestrial prey opportunistically. A deep tail and dense bones have been used to argue for underwater foraging, while buoyancy and biomechanical studies have instead supported a shoreline or shallow-water generalist. The website presents this as an open scientific question, not a settled fact.

• The original holotype no longer exists, so historical drawings and photographs are part of the anatomical evidence.
• Known bones in digital skeletal reconstructions are colour-coded by specimen because no single complete skeleton has been found.
• The famous sail may have served display, thermoregulation, fat storage or hydrodynamic functions; none of these explanations is confirmed.
• Modern reconstructions changed dramatically after a deep, paddle-like tail was described in 2020.

A research repository is not necessarily a public exhibit. Loan and display status can change, so check with the institution before visiting.

1. 01
   The Paleobiology Database

   Open source
2. 02
   Das Original des Theropoden Spinosaurus aegyptiacus nov. gen., nov. spec.

   Ernst Stromer · Abhandlungen der Königlich Bayerischen Akademie der Wissenschaften · 1915

3. 03
   New information regarding the holotype of Spinosaurus aegyptiacus Stromer, 1915

   Joshua B. Smith, Matthew C. Lamanna, Kenneth J. Lacovara · Journal of Paleontology · 2006

   Open source
4. 04
   New information on the skull of the enigmatic theropod Spinosaurus, with remarks on its sizes and affinities

   Cristiano Dal Sasso, Simone Maganuco, Eric Buffetaut, Marco A. Mendez · Journal of Vertebrate Paleontology · 2005

   Open source
5. 05
   Semiaquatic adaptations in a giant predatory dinosaur

   Nizar Ibrahim, Paul C. Sereno, Cristiano Dal Sasso · Science · 2014

   Open source
6. 06
   A reappraisal of the morphology and systematic position of the theropod dinosaur Sigilmassasaurus from the 'middle' Cretaceous of Morocco

   Serjoscha W. Evers, Oliver W. M. Rauhut, Angela C. Milner · PeerJ · 2015

   Open source
7. 07
   Tail-propelled aquatic locomotion in a theropod dinosaur

   Nizar Ibrahim, Simone Maganuco, Cristiano Dal Sasso · Nature · 2020

   Open source
8. 08
   Evaluating the ecology of Spinosaurus: shoreline generalist or aquatic pursuit specialist?

   David W. E. Hone, Thomas R. Holtz Jr. · Palaeontologia Electronica · 2021

   Open source
9. 09
   Subaqueous foraging among carnivorous dinosaurs

   Matteo Fabbri, Guillermo Navalón, Roger B. J. Benson · Nature · 2022

   Open source
10. 10
    Spinosaurus is not an aquatic dinosaur

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

    Open source