Deep-sea clawed lobster Nephropsis stewarti Wood-Mason, 1872 species complex in the Indo-West Pacific (Crustacea, Decapoda, Nephropidae), with description of a new species.

Nephropsis stewarti Wood-Mason, 1872 is the most common species of the deep-sea clawed lobster genus Nephropsis Wood-Mason, 1872 in the Indo-West Pacific. Morphological comparisons and genetic analyses of extensive material referred to this lobster revealed the presence of three species. The three species differ mainly in body size, development of the intermediate carina on the carapace, position of the lateral pair of rostral teeth, whether the pleonal tergum is granulate, and the spination on the large chelipeds. Nephropsis stewarti is restricted to the western central Indian Ocean, and a neotype is selected to fix its identity. The name Nephropsis grandis Zarenkov, 2006 is revived with neotype selection for the large form found in the West Pacific and northwestern Australia. The smaller form from southern Taiwan and the Philippines is described as Nephropsis pygmaea sp. nov.