Irritator

Irritator Fossil range: Lower Cretaceous
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Sauropsida Superorder: Dinosauria Order: Saurischia Suborder: Theropoda Family: Spinosauridae Genus: Irritator Martill et al., 1996 Species: I. challengeri Martill et al., 1996 (type)

Irritator is a genus of theropod dinosaur which was discovered in the Lower Cretaceous of the Santana Formation.

The first identifiable dinosaur from Brazil and the first non-avian from South America, Irritator has teeth similar to Spinosaurus. It has a slender jaw with nostrils well back from the front of the snout (all consistent with fish eating). It also had a large crest on the quadrate bone on top of the skull. It was named due to the feelings of the scientists who described it when they found that the snout had been artificially lengthened to resemble a plesiosaur.