Spinosaurus ("spine lizard") is a genus of large, carnivorous theropod dinosaurs known from mid-Cretaceous Africa, with most material referred to the creature having come from Egypt and Morocco.
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, crocodilian jaws and a long neck, both adaptions suited for seizing fish, which comprised most of their diets. Though no claws referred to the genus Spinosaurus are yet known, it can be inferred from its relatives that it also bore massive, hook-like claws on its hands.
Spinosaurus is estimated to have been nearly 15 meters (50 feet) long, making it the longest carnivorous dinosaur known, even longer than Tyrannosaurus and Giganotosaurus. However, it was significantly shorter than the two creatures, and whether or not it was heavier is disputed, with weight estimates ranging between 7 (lighter than Tyrannosaurus estimates) and 23 short tons (much heavier than all predatory dinosaur estimates).
In 2014, it was discovered 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.
Though many have suggested that this, combined with its webbed feet, were adaptions for swimming in deep water, a 2018 study on the buoyancy and aquatic capabilities of certain theropods, including Spinosaurus, suggests that, if its feet were not touching the floor of whatever body of water it was submersed in, it would have rolled over onto its side. This suggests that, instead of having a lifestyle revolving around swimming in deep water, it would have spent most of its time in shallow water, behaving far more like a grizzly bear or heron than a crocodile.
In The Land Before TimeA Spinosaurus, or "sharptooth", appears in The Land Before Time XII: The Great Day of the Flyers, when Guido wakes up after sleepwalking and sleep-flying all night.
Two Spinosaurus briefly appear in "The Hermit of Black Rock". Both of them resemble the dinosaur that appeared in XII, albeit in a different color possibly due to brighter lighting conditions.
Spinosaurus was carnivorous and would be referred to as a Sharptooth by the Land Before Time dinosaurs Oddly, Littlefoot, Cera, Ducky and Spike did not know what it was other than "it looked mean" (similarly to the Sarcosuchus) implying they did not know it was a Sharptooth. Guido, on the other hand claims he must be heavier due to Sharptooth drool.
- The Spinosaurus featured in XII looks similar to the one seen in Jurassic Park III.
- The Longneck Monster from Chomper's nightmare in the TV series episode, "The Lone Dinosaur Returns", appears in the same location the Spinosaurus from XII is depicted in.
- The Spinosaurus depicted in XII is very inaccurate, for multiple reasons:
- It is depicted as a fast, agile runner. Though it is unclear whether or not the recent neotype is valid, some scientists believe that, with the newly discovered short legs of the creature, it would likely be very slow and awkward on land.
- Its skull is reminiscent of Suchomimus, lacking the real animal's nasal crest and the kink in its premaxilla (upper jaw).
- Its nostrils are located on the tip of its snout, when they should be placed near its eyes.
- It is, akin to the series' Utahraptor, Deinonychus, and Allosaurus, depicted with only two fingers. Real life Spinosaurus had three fingers, likely with a large thumb.
- Its sail is similar to that of a Dimetrodon, and lacks the recently discovered kink.
- Finally, it is temporally misplaced. Spinosaurus lived from 112 to 97 million years ago, during the Albian and Cenomanian stages of the middle Cretaceous.
- Outside of The Great Day of the Flyers, Spinosaurus also makes a small appearance in The Land Before Time Animated Moviebook during a minigame, wherein it is depicted similarly to how it was often depicted in the late 1980's and early 1990's.