Genus
Valid Extinct

Irritator

Martill et al. 1996
Etymology qui irrite

Irritator is a genus of spinosaurid dinosaur that lived in what is now Brazil during the Albian stage of the Early Cretaceous Period, about 113 to 110 million years ago. It is known from a nearly complete skull found in the Romualdo Formation of the Araripe Basin. Fossil dealers had acquired this skull and sold it to the State Museum of Natural History Stuttgart. It was the subject of an ongoing international restitution dispute between Germany and Brazil, until its return to Brazil in 2026. In 1996, the specimen became the holotype of the type species Irritator challengeri. The genus name comes from the word "irritation", reflecting the feelings of paleontologists who found the skull had been heavily damaged and altered by the collectors. The species name is a homage to the fictional character Professor Challenger from Arthur Conan Doyle's novels.

Temporal range
Triassic
Jurassic
Cretaceous
Paleogene
Neogene
252 201 145 66 0 Ma
PBDB occurrences
1
Group
Dinosaures
Carnivore Ground dwelling, solitary Terrestrial
Irritator
click to enlarge
Reconstructed mount of Irritator challengeri (jr synonym = Angaturama) © Kabacchi · CC BY 2.0 · Wikimedia
PBDB Wikipedia
Classification
Dinosauria Unranked clade
Theropoda Unranked clade
Neotheropoda Unranked clade
Averostra Unranked clade
Tetanurae Unranked clade
Megalosauroidea Superfamily
Spinosauridae Family
Spinosaurinae Subfamily
Irritator Genus
Fossil sites 1 geolocated sites
Distribution
Top countries
🇧🇷 Brazil
1
Geological formations
Temporal distribution
Aptian (121.4–113.2 Ma)
1
Species (1)
Irritator challengeri 120 Ma
News 1
Irritator: Beast of the Week
Irritator: Beast of the Week
reconstruction Brazil Cretaceous Early Cretaceous Irritator
This week's beast is a special dinosaur that helps us understand more about the appearance and lifestyle of its family.  Check out Irritator challengeri!Irritator life reconstruction in watercolor by Christopher DiPiazza.Irritator was a meat-eating dinosaur that lived in what is now Brazil during the early Cretaceous period, between 113 and 110 million years ago. From snout to tail it would have measured between 20 and 26 feet (6 and 8 meters) and was a meat-eater when alive.  The genus name, Ir
24/08/2025 prehistoricbeastoftheweek
Images 1
Bibliography
Original description
D. M. Martill, A. R. I. Cruickshank, and E. Frey, P. G. Small, M. Clarke. 1996. A new crested maniraptoran dinosaur from the Santana Formation (Lower Cretaceous) of Brazil. Journal of the Geological Society, London 153:5-8 DOI ↗
Bibliography (1)
D. M. Martill, A. R. I. Cruickshank, and E. Frey, P. G. Small, M. Clarke. 1996. A new crested maniraptoran dinosaur from the Santana Formation (Lower Cretaceous) of Brazil. Journal of the Geological Society, London 153:5-8 DOI ↗