Irritator
From English/Latin irritation; named to reflect the frustration of paleontologists who discovered the skull had been heavily damaged and altered by fossil dealers
Irritator is a genus of spinosaurid dinosaur that lived in what is now Brazil during the latest Aptian to early Albian of the Early Cretaceous Period, around 113 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. 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.
Diagnosis
- Nasals with a prominent median bony crest that terminates posteriorly in a knob-like, somewhat dorsoventrally flattened projection.
- Dorsal surface of the parietals facing posterodorsally, with the vertical axis of the braincase inclined anteroventrally.
- Posterior surface of the basisphenoid with a deep, dorsoventrally oval median recess.
- Surangular with a broad lateral shelf.
Species
Irritator challengeri Martill et al., 1996
Type species
Named for Professor Challenger, the fictional character from Arthur Conan Doyle's novels, as a homage.
- Holotype
- SMNS 58022 , Staatliches Museum für Naturkunde
- Material
- Nearly complete skull, lacking the anterior portion of the snout, preserved with bones from both mandibular rami in a large calcareous concretion.
- Horizon
- Romualdo Formation, Aptian–Albian, Early Cretaceous , 121.4–100.5 million years ago
- Locality
- Buxexé, near Santana do Cariri, Ceará, Brazil Martill and colleagues (1996) report the locality as unknown. Buxexé comes from Sues and colleagues (2002), who traced it to a dealer who recognized the skull from a photograph and concluded they could not place the specimen more precisely than the unit.
Synonyms of the genus
| Name | Type | Reason |
|---|---|---|
| Angaturama | junior subjective | Sues and colleagues (2002) follow Charig and Milner (1997) in treating Angaturama limai as a subjective junior synonym of Irritator challengeri, which has priority by one month. The two holotypes preserve non-overlapping parts of the skull, so the comparison rests on published figures rather than direct examination. |
References
-
Martill, D. M.; Cruickshank, A. R. I.; Frey, E.; Small, P. G.; Clarke, M. (1996). A new crested maniraptoran dinosaur from the Santana Formation (Lower Cretaceous) of Brazil. Journal of the Geological Society 153(1): 5-8. Geological Society of London. doi:10.1144/gsjgs.153.1.0005
Gives the type horizon as the Romualdo Member of the Santana Formation; later work raises the Romualdo to formation rank.
martill1996a -
Sues, H. D.; Frey, E.; Martill, D. M.; Scott, D. M. (2002). Irritator challengeri, a spinosaurid (Dinosauria: Theropoda) from the Lower Cretaceous of Brazil. Journal of Vertebrate Paleontology 22(3): 535-547. Informa UK Limited. doi:10.1671/0272-4634(2002)022[0535:ICASDT]2.0.CO;2
Redescription of the fully prepared holotype skull SMNS 58022; corrects Martill and colleagues 1996 (maniraptoran) to Spinosauridae and treats Angaturama limai as a junior synonym.
sues2002a -
Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.
Source of the appearance features.
jones2026c - Charig, A. J.; Milner, A. C. (1997). Baryonyx walkeri, a fish-eating dinosaur from the Wealden of Surrey. Bulletin of the Natural History Museum, Geology Series 53: 11-70. charig1997a