Leptodius affinis (De Haan, 1835), belonging to the family Xanthidae, is reported for the first time from Gujarat on the western coast of India. The identification of this species is difficult as it is very morphologically similar to another closely related species, Leptodius exaratus (H. Milne Edwards, 1834). Leptodius exaratus is commonly observed in the rocky intertidal areas of the western coast of India. The carapace characters of both species are very similar; however, the morphology of the first male gonopod is the most important and reliable feature for distinguishing these two species. Recent work on these species indicated that Leptodius exaratus could be found in the western Indian Ocean, the Persian Gulf and the Red Sea, whereas Leptodius affinis occurs in waters ranging from the eastern Indian Ocean to the central Pacific Ocean. The present study reports the occurrence of Leptodius affinis on the western side of the Indian Ocean.
