Genus: Cryptosaurus SEELEY, 1869 non GEOFFROY SAINT-HILAIRE, 1833
Etymology: Greek, kryptos, “hidden, secret” and Greek, sauros, “lizard”: “Hidden lizard”.
= Cryptodraco LYDEKKER, 1889 (nomen dubium)
Etymology: Greek, kryptos, “hidden, secret” and Greek, drakon, “dragon”: “Hidden dragon”.
= Crytodraco DELAIR, 1959 (sic)
Note: Lydekker’s (1889) incorrectly believed Crytposaurus was preoccupied by Geoffroy Saint-Hilaire (1833), which was a typographical error for Cystosaurus.

Species: eumerus SEELEY, 1869 (nomen dubium)
Etymology: Greek, eu, "true" and Greek, meros, "thigh."
= Cryptodraco eumerus (SEELEY, 1869) LYDEKKER, 1889 (nomen dubium)

Holotype: SMJ. 46882

Locality: Brick pit at Great Gransden, Cambridgeshire County, England, Southern United Kingdom.

Horizon: Ampthill Clay, Marine deposits.

Biostratigraphy:

Age: Upper Oxfordian Stage, Lower Malm Epoch, Early Late Jurassic.

Material: Femur.
Note: Found with 17 associated vertebrae of a Pliosaurus.

Referred material:

BMNH R1609: Cast of the above.