Genus
Valid Extinct

Istiorachis

Lockwood et al. 2025

Istiorachis is an extinct genus of iguanodontian ornithopod dinosaur from the Early Cretaceous Wessex Formation of the Isle of Wight, England. The genus contains a single species, Istiorachis macarthurae, known from a partial postcranial skeleton including several vertebrae, incomplete ribs, and part of the pelvis. Its vertebral neural spines are notably elongated, giving the animal a 'sail-backed' appearance.

Temporal range
Triassic
Jurassic
Cretaceous
Paleogene
Neogene
252 201 145 66 0 Ma
PBDB occurrences
1
Group
Dinosaures
Herbivore Ground dwelling, gregarious Terrestrial
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PBDB ↗ Wikipedia ↗
Classification
Dinosauria Unranked clade
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Ornithischia Unranked clade
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Neornithischia Unranked clade
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Pyrodontia Unranked clade
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Cerapoda Unranked clade
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Ornithopoda Suborder
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Iguanodontia Infraorder
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Euiguanodontia Unranked clade
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Dryomorpha Unranked clade
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Ankylopollexia Unranked clade
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Styracosterna Unranked clade
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Istiorachis Genus
Fossil sites 1 geolocated sites
Distribution
Top countries
🇬🇧 United Kingdom
1
Geological formations
Wessex
1
Temporal distribution
Hauterivian (132.6–125.77 Ma)
1
Species (1)
Istiorachis macarthurae 133 Ma
Bibliography
Original description
J. A. F. Lockwood, D. M. Martill, and S. C. R. Maidment. 2025. The origins of neural spine elongation in iguanodontian dinosaurs and the osteology of a new sail‐back styracosternan (Dinosauria, Ornithischia) from the Lower Cretaceous Wealden Group of England. Papers in Palaeontology 11(4):e70034:1-38 DOI ↗
Bibliography (1)
J. A. F. Lockwood, D. M. Martill, and S. C. R. Maidment. 2025. The origins of neural spine elongation in iguanodontian dinosaurs and the osteology of a new sail‐back styracosternan (Dinosauria, Ornithischia) from the Lower Cretaceous Wealden Group of England. Papers in Palaeontology 11(4):e70034:1-38 DOI ↗