Genus: Mamenchisaurus YOUNG, 1954
Etymology: For the Manmenchi Ferry at Jinshajiang, (Upper Yangtze River), Sichuan Province, China, and Greek, sauros, “lizard”: “Mamenchi lizard”.

Species: youngi PI, QUYANG & YE, 1996
Etymology:

Holotype: ZDM 0083

Locality: Xinmin village, Zigong City, Sichuan (Szechwan) Province, China.

Horizon: Xaishaximiao Formation.

Biostratigraphy:

Age: Bathonian-Callovian Stage, Dogger Epoch, Middle Jurassic.

Material: Skull, 18 cervical, 12 dorsal, and 8 proximal, 6 mid caudal vertebrae, 7 dorsal ribs, sacrum, 3 proximal chevrons, scapulocoracoids, humeri, radii, ulnae, mani, ilium, pubis, ischia, femur, tibiae, fibulae and pes.
Note: Skin impression.
Note: Large specimen.