Abstract
During a taxonomic study of the snapping shrimp genus Alpheus from Japan and the Gulf of Thailand, it has been found that two species have been confounded under A. digitalis De Haan, 1844, which was originally described based on a single specimen possessing abnormal chelipeds. Differences between the two species are found in both morphology and coloration. Careful examination of published information of the holotype and supplemental material enable us to establish the true identity of A. digitalis. The new species, A. longiforceps, can be distinguished from A. digitalis by the more slender major chela with a sinuous, rather than convex, flexor margin, the longer male minor chela with a more elongate dactylus, and the possession of a single, rather than two, obliquely transverse white bands on the carapace and of a conspicuous dark brown spot on the lateral surface of the fourth abdominal tergum.
