Leptopterygius Huene, 1922, was erected for Leptopterygius tenuirostris, a fairly common long-snouted ichthyosaur from the English lower Liassic. Huene also referred eight other species to Leptopterygius, but these had little in common with L. tenuirostris, or with each another. These eight species have since been rejected, synonymized, or referred to other genera. Other species have also been referred to the genus since 1922, Leptopterygius having become something of a catchall for species not readily referred elsewhere. This unsatisfactory taxonomic situation is exacerbated by the recognition that the name Leptopterygius is preoccupied. A replacement name, Leptonectes, is proposed to replace Leptopterygius. Two species are referred to the new genus, L. tenuirostris (Conybeare, 1822), the type species, and Leptopterygius solei McGowan, 1993. The diagnostic features of the genus include the slenderness of the rostrum and mandible, and the wide distal expansion of the humeus, with its preaxial facet. The genus ranges from the uppermost Triassic to the Lower Jurassic.