Ichthyosaurus anningae was named by Lomax and Massare (2015) [Diagnosis—Total length to tail bend probably less than 1.5 m (comparable in length to I. breviceps and I. conybeari, but smaller than I. communis); long, fairly robust snout and mandible, snout ratio 0.60 or more, but probably <0.65 (longer than I. breviceps, within the range of I. communis, but shorter than I. conybeari); »43 presacral centra (>41 in I. communis, 42–43 in I. breviceps, <42 in I. conybeari; McGowan and Motani, 2003); »74 preflexural centra (75–79 in I. communis, >74 in I. conybeari, and <74 in I. breviceps; McGowan and Motani, 2003). Autapomorphic characters: short, robust humerus with prominent deltopectoral crest much larger than the dorsal process, and covering more than half the length of the shaft; anterior edge of humerus shaft much shorter than posterior in ventral view; circular depression on the articular surface anterior to the dorsal process of humerus; dorsoventral constriction in the humeral head; humerus length more than 1.7 times the length of the femur; femur almost as wide proximally as distally with a relatively short shaft (femur is much wider distally than proximally in all other Ichthyosaurus species).]. Its type specimen is DONMG:1983.98, a partial skeleton (incomplete skeleton comprising the skull, pectoral girdle, two humeri, anterior trunk, and scattered portions of the posterior skeleton, including two femora an), and it is a 3D body fossil. Its type locality is Charmouth area, Ichthyosaurus anningae type locality, which is in a Pliensbachian carbonate marl/mudstone in the Charmouth Mudstone Formation of the United Kingdom.