First Record of Flesh-burrowing, Fish Parasitic Isopod Genus Ichthyoxenos Herklots, 1870 (Isopoda: Cymothoidae) from India with Morphological Description of a New Species

A new species of parasitic Isopod of the genus Ichthyoxenos Herklots, 1870, is described here based on six specimens collected from the oxbow lake at Purbashtali, of East Burdwan District of West Bengal, India. This cymothoid genus is recorded for the first time from India. The new species, Ichthyoxenos aneeshi sp. nov., can be easily separated from its congeners by its distinguishing morphological characters i.e., rounded body structure; semicircular head; eyes rectangular; pereonite 1 lateral margin straight; mandible broad, molar process covered in pectinate scales, maxilla 1 with 3 setae, maxilla 2 with three segments, maxilliped comprises 4 articles; antennules shorter than antenna, comprises 7 articles, reaches only middle of the eye; antenna hardly reaches up to the distal margin of pereonite 1; antennae comprises 9 articles, terminal article without setae; pereonite 3-7 posterior margin concave; pereonite 4 widest, pereonite 7 shortest; pleotelson 0.8 times as long as maximum width, free edge straight to gently convex, median part slightly concave, longitudinal dorso-median ridge prominent; uropodal endopod and exopods without serration, subequal. Detailed morphological description along with a comparison with nearest congeners is provided in this paper; short ecological observations are also incorporated here. This is the 24th species of the genus Ichthyoxenos, Herklots, 1870.