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Irritator was a spinosaurid dinosaur that lived in what is now Brazil about 110 million years ago, during the Early Cretaceous. It is known from a nearly complete skull found in the Romualdo Formation of the Araripe Basin. The genus name reflects the irritation of paleontologists who found that the skull had been heavily damaged and altered by collectors. Estimated at between 6 and 8 meters (20 and 26 ft) in length, Irritator weighed around 1 tonne (1.1 short tons), making it one of the smallest spinosaurids known. Its long, shallow and slender snout was lined with straight and unserrated conical teeth. Lengthwise atop the head ran a thin sagittal crest, to which powerful neck muscles were likely anchored. A generalist diet—like that of today's crocodilians—has been suggested. Irritator inhabited the tropical environment of a coastal lagoon surrounded by dry regions. It coexisted with other carnivorous theropods as well as turtles, crocodyliforms, and a large number of pterosaur and fish species. (Full article...)