Which dinosaur first appeared as a major antagonist in Jurassic Park III?

Spinosaurus first appeared as a major antagonist in Jurassic Park III.

The 2001 film features a genetically recreated Spinosaurus as the dominant large predator encountered by Alan Grant and the other survivors on Isla Sorna. The animal attacks the group repeatedly and is presented as a rival to the Tyrannosaurus rex.

Jurassic Park III was the first film in the franchise to prominently feature Spinosaurus. Its portrayal became one of the film’s most debated dinosaur elements because later scientific research changed interpretations of the animal’s body shape and lifestyle.

Spinosaurus was a real Cretaceous theropod from North Africa. Fossils indicate adaptations associated with aquatic or shoreline environments, including a long, narrow snout and elongated neural spines that supported a prominent back structure.