A new, small (c. 250 mm snout-vent length) choristoderan reptile, Shokawa i
koi gen. et sp. nov., is described from the early Cretaceous Okurodani Form
ation, Tetori Group, of Japan. It is distinguished from other known chorist
oderans in having a long neck with at least 16 cervical vertebrae. The skel
eton is pachyostotic and the caudal neural spines are much taller than thos
e of the Jurassic Cteniogenys, both features suggesting a more aquatic life
style. Phylogenetic analysis places the new Japanese form in a small clade
with Cteniogenys and the Triassic Pachystropheus. This clade is the sister
taxon of crown-group Neochoristodera.