Irritator is a genus of dinosaur belonging to the family Spinosauridae. It lived during the Early Cretaceous period, approximately 110 to 105 million years ago. The first fossils of Irritator were discovered in Brazil in the 1990s, providing paleontologists with valuable insights into this dinosaur.

Irritator was a medium-sized dinosaur, estimated to have reached lengths of about 6 to 8 meters. It possessed a long and slender snout filled with sharp, conical teeth. One of its most distinctive features was a tall, narrow crest that extended along the top of its skull. This cranial crest likely played a role in display or species recognition rather than serving a functional purpose.

Irritator's long, slender snout and sharp teeth indicate its adaptation for a specialized diet of fish and other aquatic prey. It likely used its snout to snatch and grip slippery prey, aided by its robust forelimbs equipped with powerful claws. Its semi-aquatic lifestyle may have allowed it to exploit a niche that other dinosaurs couldn't, providing a unique ecological role within its ancient habitat. It coexisted with other carnivorous theropods as well as turtles, crocodyliforms, and a large number of pterosaur and fish species.