Irritator

Irritator challengeri

The genus name of Irritator challengeri records the frustration of researchers who found that its fossil skull had been altered by commercial dealers before scientific study. This spinosaurid measured about 8 meters and near 1,000 kilograms and lived during the Early Cretaceous of Brazil, roughly 145 to 100 million years ago. David Martill and colleagues described it in 1996 from the Santana Formation. Like its relatives, this piscivore had a long, narrow snout and conical teeth suited to catching fish, and it remains one of the most important records of the spinosaurid group in the Southern Hemisphere, complementing better-known forms from Africa and Europe.

Irritator gets its unusual name because paleontologists were irritated that the fossil skull had been artificially altered by commercial fossil dealers before scientific study. It is an important South American spinosaurid.

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Physical Description

Measurement	Value	Human Scale
Length	8.0 m	roughly the length of a large SUV
Height	2.5 m	—
Weight	1.0 t	comparable to 1.0 small cars

Diet & Feeding

Piscivore

Irritator was a fish-eating dinosaur. Piscivores typically lived near water sources and had specialized adaptations such as elongated snouts and conical teeth for catching fish.

Time Period

Cretaceous Early Mesozoic Era

Irritator lived during the Cretaceous Early period of the Mesozoic Era, approximately 145.0 to 100.5 million years ago.

The Cretaceous saw continued dinosaur evolution with the rise of ornithopods and early ceratopsians. Flowering plants first appeared and began to transform terrestrial ecosystems. Spinosaurus and other large theropods lived during this time.

Discovery & Naming

Named By	David Martill et al.
Discovery Year	1996
Discovery Location	Santana Formation, Brazil

Classification

Dinosauria → Saurischia → Theropoda → Spinosauridae → Irritator

Spine lizards

Large theropods with elongated snouts and conical teeth adapted for catching fish. Spinosaurus is the largest known predatory dinosaur, estimated at 15-18 meters long.