Akidostropheus

Akidostropheus
Temporal range: Late Triassic
(Norian), ~
Reconstructed skeleton
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauromorpha
Clade: Tanysauria
Family: Tanystropheidae
Genus: Akidostropheus
Schubul, Marsh & Kligman, 2025
Species:
A. oligos
Binomial name
Akidostropheus oligos
Schubul, Marsh & Kligman, 2025

Akidostropheus (meaning "spike joint") is an extinct genus of tanystropheid archosauromorph reptiles known from the Late Triassic of what is now Arizona, United States. The genus contains a single species, Akidostropheus oligos, discovered in the early 21st century and named in 2025. It is known from several isolated vertebrae found in the Chinle Formation, which dates to the Norian age.

Akidostropheus is a small-bodied animal. Its vertebrae are very unique, as the neural spines bear elongated spikes. These would have formed a row of pointed spines running along the animal's neck, back, and tail. They may have served a defensive function to deter predators. Akidostropheus may be closely related to Tanytrachelos.