Genus: Leviathanochelys CASTILLO-VISA, LUJAN, GALBART & SELLES, 2022
Etymology: Leviathan, in reference to the Biblical marine beas, in allusion to the body size of the news speciesl and Latinized Greek, chelys, "turtle."

Species: aenigmatica CASTILLO-VISA, LUJAN, GALBART & SELLES, 2022
Etymology: Latinized adjective from the Greek noun, ainigma, "enigma, conundrum or riddle"; in reference to the peculair anatomical characteristics of its pelvis and carapce.

Holotype: MCD9884

Locality: Cal Torrades, Coll de Nargo, Lleida PRovince, Catalonia, North-eastern Spain.

Horizon: Lower part, Perles Formation.

Biostratigraphy:

Age: Campanian Stage, Senonian Subepoch, Gulf Epoch, Late Cretaceous.

Material:

MCD9884a: Posteror portion of the carapace including the neural plates 5-8, boht left and right fragmentary costals 5-8 and putative verteral cenra, nearly unidentifible.

MCD9884b: Partial pelvic girdle, including the left pubis.

MCD9884c: Right pubis.

MCD9884d: Left ischium.

MCD9884e: Right iscihum.

MCD9884f: Left ilium.

MCD9884g: Right ilium.