Wahlisaurus massarae was named by
Lomax (2017) [Small-bodied leptonectid ichthyosaur with the following autapomorphies: coracoid with a large, ovoid foramen, a coracoid foramen is present in Cymbospondylus but it is much smaller in this genus; presence of both a coracoid foramen and scapular-coracoid foramen (fenestra coracoscapularis), the latter formed by articulation of the coracoid and scapula; a coracoid with a posterior notch that is much more developed than the anterior notch. Three other features may be utapomorphies: humerus deltopectoral crest prominent and 2.5 times greater than the dorsal process; dorsoventral width of the humerus is greater than the anteroposterior width, which results in a D-shape in proximal view; and slender, long, needle-like teeth with marginally recurved crowns and large, bulbous infolded roots. Wahlisaurus massarae is also characterized by the following combination of features shared with other taxa: very slender, delicate and relatively long snout (as in all leptonectids) with mandible shorter than snout, which produces an overbite (shared with Eurhinosaurus, Excalibosaurus and some specimens of Leptonectes tenuirostris); basioccipital with extensive extracondylar area (as in Ichthyosaurus, Excalibosaurus, Eurhinosaurus and Leptonectes tenuirostris and all other non-ophthalmosaurid ichthyosaurs); coracoid anteroposteriorly longer than mediolaterally wide (as in some specimens of several taxa including Stenopterygius, Hauffiopteryx, Leptonectes tenuirostris, Ichthyosaurus and Ophthalmosaurus); extensive contact between the anterolateral border of coracoid (lateral scapular facet and medial scapular facet) and scapula forms a small, semi-circular scapularcoracoid foramen, similar contact has been reported in some specimens of Stenopterygius and Paraophthalmosaurus and is here noted in some specimens of Leptonectes tenuirostris, but the coracoid-scapular foramen is much larger, deeper and ovoid in those taxa; a small, emarginated anterior notch in coracoid (as in the holotype of Excalibosaurus and also in Suevoleviathan); a well-developed posterior notch in the coracoid (as in Ichthyosaurus); long scapula with greatly expanded proximal region but without prominent acromion process (as in Leptonectes moorei, Eurhinosaurus, Excalibosaurus and Ichthyosaurus); long femur with thin, slender shaft and distal end wider than proximal (as in Leptonectes tenuirostris); notched tibia (as in several Lower Jurassic ichthyosaurs including Temnodontosaurus, Stenopterygius, Leptonectes tenuirostris and Ichthyosaurus conybeari); pelvis tripartite with pubis widely expanded distally and approximately equal in size to ischium (as in some specimens of Ichthyosaurus and Leptonectes tenuirostris).]. Its type specimen is LEICT G454.1951.5, a partial skeleton (Partial skull and an associated incomplete skeleton comprising the pectoral girdle, humeri, pelvic elements, partial hind fins, vertebrae and ribs.), and it is a 3D body fossil. Its type locality is
Wahlisaurus-type locality, which is in a Hettangian marine horizon in the Scunthorpe Mudstone Formation of the United Kingdom.