Spinosaurus

*Spinosaurus aegyptiacus*

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* Stan Winston Artwork
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***Spinosaurus*** ("spine lizard") is a genus of large, carnivorous theropod dinosaur known from mid-Cretaceous Africa, with most material referred to the creature having come from Egypt and Morocco. They were among the largest theropod dinosaurs to have ever lived.

## Description

The most notable feature of *Spinosaurus* was a row of tall spines that adorned its back, which are believed to have supported a sail in life, not unlike *Ouranosaurus* and the non-dinosaur *Dimetrodon*. It has been theorized that this "sail" would have been used for display purposes, to attract mates and intimidate rival spinosaurs.

*Spinosaurus*, like its relatives *Baryonyx* and *Suchomimus*, had sleek jaws like those of species of long snouted crocodilians (such as orinoco crocodiles and Australian freshwater crocodiles) and gharials, along with a long neck, both adaptions suited for seizing aquatic prey, which comprised a part of their diets (evidence exists that suggests spinosaurids also ate other animals, including pterosaurs and other dinosaurs).

    Also like *Baryonyx* and *Suchomimus*, it bore massive, hook-like claws on its hands.

In 2020, it was described that *Spinosaurus* possessed a somewhat paddle-like tail, suggested by the authors of the paper to have been for underwater propulsion. It has also been suggested that the tail may have acted as a secondary display structure.

### Size

*Spinosaurus* is estimated to have been able to reach lengths of up to 15 - 16 meters (50 - 52 feet) from large specimens, making it the longest carnivorous dinosaur known, even longer than *Tyrannosaurus* and *Giganotosaurus* - some extreme estimates from prior to 2014 suggested that it could reach lengths of nearly 18 meters (60 feet). However, it was likely not as tall as the two creatures if its legs were as short as what was proposed by Ibrahim *et al.*. Modern estimates for the weight of larger *Spinosaurus* place them around 6.5 - 7.5 tons, lighter than some species other theropods of similar length. Earlier weight estimates range between 6 (lighter than most *Tyrannosaurus* estimates) and 23 short tons (exceedingly unlikely given how light the dinosaur's build was, and much heavier than all known predatory dinosaur estimates and some species of sauropods).

### Legs

    In 2014, material was described revealing that its legs were much shorter than those of its relatives, to such a degree that some have proposed that it was restricted to a quadrupedal gait when on land; others have suggested that it assumed a stance not unlike that of a pangolin. The find and the *Spinosaurus* specimen in question (named FSAC-KK 11888) have been questioned - some have proposed that the legs belong to a younger *Spinosaurus* than the rest of the specimen in the Ibrahim study (which would mean that it is chimeric, a mix of separate spinosaurs). Regardless of whether or not FSAC-KK 11888 is a chimera, *Spinosaurus* still would have had significantly proportionately shorter legs than its relatives in life.

## Paleobiology

Many have suggested that several of *Spinosaurus's* anatomical traits, including its unusually small hind legs and its possibly-webbed feet, were adaptations for swimming in deep water, a suggestion bolstered by the description of a *Spinosaurus* tail, which was thin, flexible and bore a "sail", and would very likely have been used as a means of propulsion like the tail of a crocodilian. A 2022 paper bolstered the notion of a largely-aquatic *Spinosaurus*, indicating that it and one of its relatives, *Baryonyx*, possessed very dense bones, a trait found in several animals that aids their ability to dive underwater. The same paper found that another spinosaurid, *Suchomimus*, had less dense bones than *Spinosaurus* and *Baryonyx* and likely spent more of its time on land than either of its relatives.

The proposed largely aquatic lifestyle of *Spinosaurus* has been contested. It has been suggested that *Spinosaurus* may have been too buoyant to dive properly and that it may have been an ineffective swimmer, and it has been noted that some *Spinosaurus* fossils have been excavated from locales that would have been far inland when the genus was still extant. Regardless of whether or not it was adapted for active underwater life, it has still been suggested that it would have spent much of its time in and around shallow water.

## JPInstitute.com Description

The star of "Jurassic Park III," the Spinosaurus is one of the strangest of the large meat-eaters. What makes it so different is the large sail on its back, formed by spines that grew as tall as six feet. No one knows exactly why it had these on its back, but it is possible that they helped to regulate body temperature, or maybe they were used as a display during courtship. The other really interesting thing about this huge dinosaur was its diet - it seems to be designed to eat mostly fish!

The teeth of Spinosaurus are designed differently from any of the large carnivores. They are long and conical-shaped, the kind found on reptiles that eat mostly fish. How could something this large be so specially designed to eat mostly fish? It probably lived along the shore where fairly large fish were abundant. Of course, it could also have eaten just about anything else it could catch.

What is interesting is that there were two other dinosaurs living at the same time and in the same vicinity as Spinosaurus who also had large sails on their backs. What was it about this region that gave rise to this body type?

At one time, there was an almost complete specimen on display in a museum in Germany. However, it was completely destroyed and lost forever during the bombing of Germany in WWII.

## Dinosaur Field Guide Description

Spinosaurus ("'spine lizard") is one of the most spectacular dinosaurs ever found. It was an enormous meat-eating dinosaur, as big as Tyrannosaurus rex. But its jaws and teeth were very different from T. rex's The jaws were long and slender, and the teeth were cone-shaped, like those of a crocodile. Its most distinctive feature, however, was the huge sail-like fin on its back. This sail was made from the spines that come out of the top of the backbones of dinosaurs and all other backboned animals. If you feel down your spine from the bottom of your head, you'll feel a series of bumps (especially at the base of the neck). These bumps are the same bumps on the top of backbones of dinosaurs. The spines of Spinosaurus, though, were tremendous: The longest one found was over 5 feet (1.7 m) tall! What would have been the purpose of such a sail? Although Spinosaurus lived in a swampy coastal environment, the sail would not have been used like the sail of a boat. Instead, it may have served to let Spinosaurus cool itself down if it got too hot. The skin on the sail, like all skin, would have been filled with blood vessels. Hot
blood pumped into the sail would be cooled off, especially if there was a breeze; African elephants use blood vessels in their ears for this purpose. Also, the sail might have been used to show off to other Spinosaurus, either to attract a mate or to defend its territory. Additionally, the dinosaur may have used its sail to make itself look bigger. Living in the same environment as Spinosaurus were a couple of other giant predators, Carcharodontosaurus and Deltadromeus. If a Spinosaurus turned itself sideways toward an attacker, it would suddenly look much larger, and so the other predator might think twice about attacking. Modern cats do something similar: When they get scared, they puff up their fur to make themselves look larger.

### Fun Facts

Old pictures of Spinosaurus showed it incorrectly with a Tyrannosaurus-like skull.

### Trivia

Spinosaurus is not the only dinosaur with a sail. Ouranosaurus (a relative of Iguanodon) also had a sail. The sail-backed Dimetrodon of the Permian Period was not a dinosaur. It was, in fact, a primitive synapsid (or protomammai), more closely related to the ancestors of mammals.

## Appearance in other media

### *Jurassic Park*

* *Spinosaurus* has become an iconic dinosaur and its fame started with the film, *Jurassic Park III*, the first Jurassic Park film not based on a Michael Crichton book. *Spinosaurus* was portrayed as the main "villain" that caused destruction in its path. In an infamous scene, this *Spinosaurus* was seen fighting a *Tyrannosaurus rex* and defeating it. A *Spinosaurus* fossil Skeleton was seen in *Jurassic World* where it was destroyed by the *Tyrannosaurus,* Rexy, during the Isla Nublar Incident of 2015. It is also one of the dinosaurs included in the Holoscape of Innovation Center, though it is unknown if *Spinosaurus* actually lives in Jurassic World. *Spinosaurus* also apparently into cruelty after the Isla Nublar Incident of 2015 before *Jurassic World: Fallen Kingdom*, on Isla Nublar, though it's unknown if there were any surviving populations left. However, it was planned to be in *Jurassic World: Fallen Kingdom* has a rematch with the *T. rex* before being cut from the film entirely. *Spinosaurus* also appears in most of the Jurassic Park expanded the universe, including games and toy lines.

* *Spinosaurus* appears in the game *Jurassic World: Evolution*. It is based on the *Jurassic Park III* variant.

* *Spinosaurus* does appear in the game Jurassic World: Alive with the same design as it does in Jurassic Park III.

* *Spinosaurus* appears in the game Jurassic World: The Game.

### *The Land Before Time*

* *Spinosaurus* also appears in the 12th episode of The Land Before Time television series but is inaccurately shown with only two fingers. It was also a minor antagonist in the Land Before Time XII: the Great Day of the Flyers.

## Links

http://web.archive.org/web/20040408122248fw\_/http://www.jpinstitute.com/dinopedia/dinocards/dc\_spino.html#

## References

1. ↑ 1.0 1.1 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6098948/
2. ↑ https://www.nature.com/articles/s41586-020-2190-3
3. ↑ https://www.nationalgeographic.com/science/2020/04/spinosaurus-graphic-reconstructing-gigantic-aquatic-predator/
4. ↑ https://www.nhm.ac.uk/discover/news/2022/march/spinosaurus-baryonyx-may-have-hunted-fish-underwater.html
5. ↑ Subaqueous foraging among carnivorous dinosaurs | Nature
6. ↑ Spinosaurus is not an aquatic dinosaur | eLife