''Shokawa'' is an extinct genus of

choristoderan Choristodera (from the Greek χωριστός ''chōristos'' + δέρη ''dérē'', 'separated neck') is an extinct order of semiaquatic diapsid reptiles that ranged from the Middle Jurassic, or possibly Triassic, to the Miocene (168 to 20 or p ...

diapsid Diapsids ("two arches") are a clade of sauropsids, distinguished from more primitive eureptiles by the presence of two holes, known as temporal fenestrae, in each side of their skulls. The earliest traditionally identified diapsids, the araeosc ...

reptile Reptiles, as commonly defined, are a group of tetrapods with an ectothermic metabolism and Amniotic egg, amniotic development. Living traditional reptiles comprise four Order (biology), orders: Testudines, Crocodilia, Squamata, and Rhynchocepha ...

, known from the

Lower Cretaceous Lower may refer to: * ''Lower'' (album), 2025 album by Benjamin Booker * Lower (surname) * Lower Township, New Jersey *Lower Receiver (firearms) * Lower Wick Gloucestershire, England See also * Nizhny {{Disambiguation ...

of Japan. It is only known from one species, ''Shokawa ikoi.'' The only known remains are a postcranial specimen lacking the skull, discovered at the KO2 locality in sediments belonging to the

Okurodani Formation The Okurodani Formation is an Early Cretaceous geologic Formation (geology), formation in central Honshu, Japan. Part of the Tetori Group, it primarily consists of freshwater continental sediments deposited in a floodplain environment, with occasi ...

near the village of

Shokawa ''Shokawa'' is an extinct genus of choristoderan diapsid reptile, known from the Lower Cretaceous of Japan. It is only known from one species, ''Shokawa ikoi.'' The only known remains are a postcranial specimen lacking the skull, discovered at th ...

Gifu Prefecture is a Prefectures of Japan, prefecture of Japan located in the Chūbu region of Honshu. Gifu Prefecture has a population of 1,910,511 () and has a geographic area of . Gifu Prefecture borders Toyama Prefecture to the north; Ishikawa Prefecture ...

. ''Shokawa'' possessed a long neck with at least 16

cervical vertebrae In tetrapods, cervical vertebrae (: vertebra) are the vertebrae of the neck, immediately below the skull. Truncal vertebrae (divided into thoracic and lumbar vertebrae in mammals) lie caudal (toward the tail) of cervical vertebrae. In saurop ...

, and closely resembles and is closely related to the smaller choristoderan, ''

Hyphalosaurus ''Hyphalosaurus'' (meaning "submerged lizard") is a genus of freshwater aquatic reptiles, belonging to the extinct order Choristodera. They lived during the early Cretaceous period (late Barremian to early Aptian age), about 123-120 million year ...

''.The dentary of a Choristodere (Reptilia: Archosauromorpha) from the Okurodani Formation, Tetori Group (Lower Cretaceous) of Japa

/ref> The generic name refers to the village near where it was found, while the specific name honors the collector of the first specimen, one Mr. Ikoi Shibata. Phylogeny from the analysis of Dong and colleagues (2020):

References

Choristodera Early Cretaceous reptiles of Asia Extinct animals of Japan Fossils of Japan Prehistoric reptile genera {{paleo-reptile-stub