Irritator

Phylogeny: Dinosauria > Saurischia > Neotheropoda > Tetanurae > Megalosauroidea (?) > Spinosauridae > Spinosaurinae

Overview: The holotype specimen of this carnivorous dinosaur consisted of a partial skull and portions of the lower jaws, originally unearthed in northeastern Brazil. These bones weren’t found by paleontologists, however, but by fossil poachers intending to sell to private collectors. Sometime after, the remains wound up in Germany, where researchers were able to analyze them. At first, the skull was reported as that of a giant pterosaur (flying reptiles like Pteranodon), though its dinosaurian affinities would soon be recognized. How it fit in amongst other dinosaurs, however, wasn’t fully clear at that time. We know now that this animal belonged to the family Spinosauridae, fossils of which had been known since at least the 1910’s, but even as late as the 1990’s, spinosaurids were poorly understood. Spinosaurids are often classified in the megalosauroid superfamily, which if accurate, made them relatives of dinosaurs like Megalosaurus, in the Megalosauridae. However, in recent studies, spinosaurids have been found to potentially belong to the clade Carnosauria

Paleontologists would formally describe Irritator as a genus in 1996. Irritator takes its name from the irritation these scientists felt upon realizing its discoverers had artificially lengthened and altered the skull with plaster prior to selling, hoping a larger skull would fetch a higher price. Due to this, preparation of the specimen took significantly longer than expected. Other spinosaurid fossils have also been unearthed in Brazil, including those referred to a genus called Angaturama, which was also formally named in 1996. Later studies have found that the two were probably the same animal. Irritator was described first, so its name has priority. This would increase the known material of Irritator to include other parts of the body. It appears to have been an average-sized spinosaurid of maybe seven or eight meters in length. Irritator, like other spinosaurids, had a narrow, elongated snout. The jaws were lined with conical teeth, similar to those of a crocodile, implying a diet of fish and other aquatic prey, though they ate other animals as well. One specimen was found to have consumed parts of a pterosaur.