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beaked plant-eater
Istiorachis
Say it like this: “ISS-tee-oh-RAH-kiss”
Istiorachis macarthurae
Istiorachis ate plants and walked on two or four legs. It lived in the Early Cretaceous. Bones have been found in the United Kingdom.
- When
- Early Cretaceous (Barremian) · roughly 125.8 to 121.4 million years ago
- Named in
- 2025 · Lockwood, J. A. F.; Martill, D. M.; Maidment, S. C. R.
- Hip height
- Not established
- Length
- Not established
- Weight
- Not established
- Found in
- the United Kingdom · Wessex
- Food and walking
- Herbivore · Two or four legs
- Kind
- beaked plant-eater · Ornithopod
- Family branch
- Styracosterna
The story in short
Istiorachis was formally named in 2025 by J. A. F. Lockwood and colleagues. The name means “sail spine.”
Fossils referred to Istiorachis date to the Early Cretaceous (Barremian), roughly 125.8 to 121.4 million years ago. Finds come from the United Kingdom, including the Wessex Formation. It was a herbivore and could move on two or four legs.
The fossils of Istiorachis are too incomplete for a responsible length, hip height, or weight, so those fields are left blank on purpose.
On the family tree it sits in Styracosterna, among the ornithopod dinosaurs.
Close relatives
Bayannurosaurus
Bayannurosaurus perfectus
Early Cretaceous (Aptian) · roughly 121.4 to 113.2 million years ago
Calvarius
Calvarius rapidus
Late Cretaceous (Maastrichtian) · roughly 72.2 to 66 million years ago
Cedrorestes
Cedrorestes crichtoni
Early Cretaceous (Aptian) · roughly 121.4 to 113.2 million years ago