Abstract Members of the fish parasitic isopod family Cymothoidae usually parasitize a host fish by a single species infestation. For the first time from Indian waters two species of cymothoids, the body surface infesting Anilocra grandmaae Aneesh, Hadfield, Smit and Kumar, 2021 and the branchial infesting Agarna malayi Tiwari, 1952, were reported simultaneously parasitizing the same individual toli shad, Tenualosa toli (Valenciennes, 1847). Each double-infested T. toli harboured an ovigerous female of A. grandmaae and an ovigerous female and male of A. malayi. Out of 814 host fishes collected from seven different localities, along the Kerala coast, southwest coast and Bay of Bengal coast, 113 fishes were infested with only A. malayi and 71 individuals were infested with only A. grandmaae. Interestingly, nine individuals of T. toli harboured both A. malayi and A. grandmaae simultaneously. Cymothoid co-occurrence is rarely reported, and this is the first report of two cymothoid species infesting a single fish host from India. Globally, it is the third record of simultaneous occurrence of two cymothoids and the first record of body surface and branchial cymothoids parasitising the same individual fish.

Abstract Mursia spiridonovi Karasawa, 2018 known only from the western Indian Ocean, is the smallest species of the genus, measuring only 18 mm in carapace length. The species is redescribed from fresh material collected in Tamil Nadu in southern India. It is compared with similarly sized specimens of M. bicristimana Alcock and Anderson, 1894, all of which are immature. Mursia spiridonovi is characterised not only by its occurrence in shallow waters (less than 300 m depth) and small adult size but also by the prominently granular carapace and structure of the cheliped merus, male pleonal somites and gonopods.

Abstract This paper describes two new species of parasitic copepods of the family Chondracanthidae H. Milne Edwards, 1840. Acanthochondria krishnai sp. n. is described from Dollfus' stargrazer, Uranoscopus guttatus Cuvier, collected from Muttom and Colachel, Tamil Nadu, and Chondracanthus kabatai sp. n. from Silvery john dory, Zenopsis conchifer Lowe, collected from Neendakara, Quilon, Kerala, both along the southwest coast of India. Both the species are described and illustrated based on the fresh female and male specimens collected from India. Both the species are the first Indian representative of the respective genera. The checklist of Indian species of the family Chondracanthidae is also presented.