Istiorachis

Istiorachis
Temporal range: Early Cretaceous,
Reconstructed skeleton with a human for scale
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Dinosauria
Clade: Ornithischia
Clade: Ornithopoda
Clade: Ankylopollexia
Clade: Styracosterna
Genus: Istiorachis
Lockwood, Martill & Maidment, 2025
Species:
I. macarthurae
Binomial name
Istiorachis macarthurae
Lockwood, Martill & Maidment, 2025

Istiorachis (meaning "sail spine") is an extinct genus of iguanodontian ornithopod dinosaur from the Early Cretaceous (Barremian age) 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.