Genus: Hastanectes BENSON, KETCHUM, NAISH & TURNER, 2012
Etymology: In reference to Hastings, East Sussex County, England, where the specimen was found, and Greek, nectes, 'swimmer'.

Species: valdensis (LYDEKKER, 1889) BENSON, KETCHUM, NAISH & TURNER, 2012
= Cimoliasaurus valdensis (LYDEKKER, 1889) (nomen dubium)
= Cimoliosaurus valdensis LYDEKKER, 1889 (sic)
Etymology:
= Plesiosaurus valdensis (LYDEKKER, 1889) KOKEN, 1905 (nomen dubium)

Holotype: BMNH R609

Locality: Hastings, (TQ 831095-TQ 853105), East Sussex County, England, Southern United Kingdom.

Horizon: Wadhurst Clay, Hastings Beds, (Ashdown Beds, Tunbridge Wells Sand).

Biostratigraphy:

Age: Berriasian-Valanginian Stage, Lower Neocomian Subepoch, Lower Early Cretaceous Subepoch, Early Cretaceous.

Material: Cervical, dorsal and caudal vertebrae.

Referred material:

LYDEKKER, 1889

Locality: Near St. Leonards, England, Southern United Kingdom.

Horizon: Wadhurst Clay.

Biostratigraphy:

Age: Berriasian-Valanginian Stage, Lower Neocomian Subepoch, Lower Early Cretaceous Subepoch, Early Cretaceous.

Material:

BMNH R 1612: Imperfect neural arch of a dorsal vertebra.

BMNH R 1612a: The centrum of a caudal vertebra.

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