Irritator

Filed under Cretaceous dinosaurs · Types of Dinosaurs editorial team

Order: Saurischia · Suborder: Theropoda · Infraorder: Megalosauroidea · Family: Spinosauridae

Irritator was a spinosaurid theropod dinosaur that inhabited the waterways of Early Cretaceous Brazil. Measuring between 20 and 26 feet in length, this piscivorous predator possessed the characteristic features of its family: a long, narrow snout and conical teeth perfectly adapted for catching fish. The dinosaur's name reflects an unexpected chapter in its scientific history—paleontologists studying the specimen discovered that collectors had altered the fossil before it reached researchers, prompting frustration that led to its memorable designation.

The most significant fossil evidence for Irritator comes from a well-preserved skull that has provided invaluable insights into spinosaur anatomy. As one of the better-documented South American members of the Spinosauridae family, Irritator has played an important role in helping scientists understand how these distinctive theropods were structured and how they hunted. The fossil record suggests that Irritator, like its spinosaurid relatives, was intimately tied to aquatic environments, likely prowling rivers and coastal areas in search of prey. Through continued study of specimens like Irritator, paleontologists have deepened their knowledge of this remarkable group of dinosaurs and their ecological roles in Cretaceous ecosystems.

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Reference background: Natural History Museum, London — Dinosaurs; Smithsonian National Museum of Natural History — Dinosaurs; American Museum of Natural History — Dinosaurs & Fossils. Figures are typical published ranges; taxonomy follows the source era and modern consensus is noted where it differs. See our sources & fact-check policy.

Related dinosaurs

Other dinosaurs from the Spinosauridae family.