Spinosaurus ("spine lizard") is a genus of large, carnivorous theropod dinosaurs, the largest of the theropods that have currently been discovered.
They had a fin on their back much the same as Ouranosaurus and Dimetrodon did, but bigger. They were first discovered in Africa in the early 20th century. They lived around 100-93 million years ago, during the Albian and Cenomanian stages of the Cretaceous period.
In mid 2014, Spinosaurus was discovered to have had much smaller hind legs than previously believed, to such an extent that some believe that it was restricted to a quadrupedal gait when on land. Now, it is believed that Spinosaurus spent most of, if not all of its time in the water. Living mostly in freshwater marshes, it preyed on large species of freshwater fish alive around the same time with the aid of its strong arms and sleek, crocodilian jaws.
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. He landed on its back. It actually gets Guido into its mouth but spat him out after he tickles its mouth with one of his feathers. It snaps at Guido again but Petrie swoops down and picks him up. Spike accidentally knocks Littlefoot, Cera and Ducky off the ledge they were on, distracting the predatory creature. It chases the six dinosaurs between two rocks and gets stuck in them, cause his spine or sail was too large to get through of those rocks when its been caught, trying to get out. The gang has enough time to make their escape back into the Great Valley while the Sharptooth struggles to free itself.
Two Spinosaurus briefly appear in The Hermit of Black Rock. Petrie and Guido see them while riding on Swooper. When Swooper suggests landing to take a rest Petrie and Guido see them below. Both of them resemble the dinosaur that appeared in XII, albeit in a different color due to brighter lighting conditions.
They were carnivores and would be referred to as sharpteeth 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 is the largest carnivorous dinosaur, even larger than Tyrannosaurus and Giganotosaurus.
- The Spinosaurus featured in XII looks similar to the one seen in Jurassic Park 3.
- 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.