Species: angulata HIRAYAMA, SAKURAI, CHITOKU, KAWAKAMI & KITO, 2002
Etymology: Latin, angulata, "angulate"; in respect ot nuchal bone
with lateal ‘horns’.
Holotyep: HMG 1056
Locality: Tosano-sawa River, Tomiuchi District, Hobetsu-cho, Hokkaido Prefecture, Hokkaido Island, Japan.
Horizon: Yezo Supergroup.
Biostratigraphy:
Age: Late Cretaceous.
Material: large part of carapace with partial plastron attached.