Discovery of the shrimp Pycnocaris chagoae Bruce, 1972 (Decapoda: Caridea: Gnathophyllidae) in the Lakshadweep Archipelago, India

The caridean shrimp family Gnathophyllidae currently comprises five genera: Gnathophyllum Latreille, 1819; Gnathophylloides Schmitt, 1933; Pycnocaris Bruce, 1972; Levicaris Bruce, 1973a and Gnathophylleptum d’Udekem d’Acoz, 2001, the last three genera being monotypic (De Grave et al., 2009). The original description of Pycnocaris chagoae Bruce, 1972 was based on a pair of specimens collected in the Chagos Archipelago, central Indian Ocean (Bruce, 1972). Further information on the morphology and colour pattern of P. chagoae as well as its association with the holothurian hosts Holothuria cinerascenes Brandt and Labidodemas rugosum Ludwig was provided by Bruce (1973, 1983). Since the last record by Bruce (1983), no further specimens of P. chagoae have been reported. During a survey of the intertidal zone on the east side of Agatti Island, Lakshadweep (formerly Laccadive Archipelago), India, in February 2011, a pair of P. chagoae was observed clinging to the ventral surface of a holothurian collected under rocks and preliminarily identified as Labidodemas sp. (Fig. 1A). Both shrimps and their holothurian host were carefully transferred to the laboratory; colour photographs of the shrimps on their host were taken using a Nikon SLR camera. The specimens are preserved in 5–10% sea water formalin and deposited in the National Zoological collections of Marine Biological Regional Centre (MBRC), Zoological Survey of India (ZSI), Chennai, Tamilnadu. Size is expressed as total length (tl in mm) from the tip of the rostrum to the posterior margin of the telson and carapace length (cl in mm) from the posterior orbital margin to the posterior margin of the carapace.