Temporal range: Lower Cretaceous
Martill et al., 1996
Martill et al., 1996 (type)
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.