The giant clam commensal shrimp Anchistus miersi (de Man, 1888) (Decapoda: Palaemonoidae) new to Lakshadweep Sea, India

Abstract

The genus Anchistus Borradaile, 1898 is a colourful shrimp from the commensal group. In this study, we are reporting a new occurrence of Giant Clam commensal shrimp Anchistus miersi (de Man, 1888 [in de Man, 1887–1888]) caught from Agatti Island, Lakshadweep Sea during February 2020. The present specimens (one each matured male and female) were collected from the mantle cavity of the Giant Clam, Tridacna maxima (Roding, 1798) in the coral lagoon at a depth of 4 m. Anchistus miersi is morphologically very similar to Anchistus demani, which is easily distinguished by the presence of a strong antennal spine and conspicuous accessory spinules in the third─fifth pereopods and presence of small blue spots all over the body. The molecular analysis confirms that, the morphological identification of the present Indian specimens displays an intraspecific genetic divergence of 0.3─1.2%.  Besides, the remarkable taxonomic features and colour patterns, distributional ranges are also attested with the report of the species from the present area.