Sinemys is an extinct genus of turtle from the Late Jurassic to Early Cretaceous of China and Japan. Three species have been named: S. lens, the type species, from the Kimmeridgian-Tithonian of Shandong; S. gamera (Japanese: シネミス・ガメラ) (named after the movie monster of the same name), from the Valanginian-Albian of Nei Mongol; and S. wuerhoensis, from the Aptian-Albian of Xinjiang.[1] The species S. gamera is noted for the presence of a pair of elongate spines projecting outwards and backwards from seventh costal of the carapace. These may have served a hydrodynamic function.[2]