A new alpheid shrimp of the genus Betaeus from the Pacific coast of central Japan (Crustacea: Decapoda: Caridea)

A new alpheid shrimp, Betaeus gelasinifer, is described and illustrated from the Pacific coast of central Honshu, Japan. The new species is characterized by a set of the following characters: the frontal margin of the carapace is moderately indented; the palm of the first pereiopod is relatively deep and usually bears a shallow excavation on the ventral surface; the lateral surface of the palm of the first pereiopod lacks granules, tubercles or setae; the mesial spine at the posterolateral corner of the telson is noticeably elongate; and the endopod of the uropod overreaches the posterior margin of the telson by 0.3 of its length. It represents a second species of the genus from Japanese waters. A brief note on the taxonomy of the genus is provided.