taxonID	type	description	language	source
61139E33C753196D3001FA57FA9F76EC.taxon	materials_examined	Type species. Agarna cumulus (Haller, 1880).	en	Kumar, Panakkool Thamban Aneesh Helna Ameri Kottarathil Appukuttannair Biju (2022): Simultaneous double parasitism by the parasitic cymothoids (Crustacea: Isopoda) of two genera on a single host fish Tenualosa toli from India. Nauplius (e 2022013) 30: 1-8, DOI: 10.1590/2358-2936e2022013, URL: https://doi.org/10.1590/2358-2936e2022013
61139E33C753196A30A1F8C1FDBA7594.taxon	description	(Fig. 1 B, C)	en	Kumar, Panakkool Thamban Aneesh Helna Ameri Kottarathil Appukuttannair Biju (2022): Simultaneous double parasitism by the parasitic cymothoids (Crustacea: Isopoda) of two genera on a single host fish Tenualosa toli from India. Nauplius (e 2022013) 30: 1-8, DOI: 10.1590/2358-2936e2022013, URL: https://doi.org/10.1590/2358-2936e2022013
61139E33C753196A30A1F8C1FDBA7594.taxon	biology_ecology	Host. Tenualosa toli (Clupeidae), Nematalosa nasus (Bloch, 1795) (Clupeidae), and Mugil ophueseni (Bleeker, 1858) (= Valamugil cunnesius (Valenciennes, 1836) (Mugilidae) (Tiwari, 1952; Pillai, 1954; 1964; Aneesh et al., 2016; 2018; present study). Distribution. Kolkata (Tiwari, 1952), Travancore (Pillai, 1954; present study), Kayamkulam Lake, Kerala, southwest coast of India (Pillai, 1964; present study), Bay of Bengal and Malabar coast of Kerala, India (Aneesh et al., 2016; 2018; present study). Remarks. Agarna malayi was described by Tiwari (1952) based on the materials collected from N. nasus from Kolkata. Later, Pillai (1964) reported and redescribed based on the materials collected from M. ophueseni (Bleeker) off the Kerala coast. Recently the species is redescribed based on the examination of the type material and several fresh specimens collected from Kerala coast and by considering all lifecycle stages (see Aneesh et al., 2018). Agarna malayi can be well separated from other branchial cymothoids by its largely hunched body; the shape of the cephalon and pereonite 1; body strongly recurved towards one side; cephalon roughly triangular with narrow round apex, accommodated in the deeply recessed amphicephalic process of pereonite 1; the presence of many pustules on the dorsal surface of pleotelson.	en	Kumar, Panakkool Thamban Aneesh Helna Ameri Kottarathil Appukuttannair Biju (2022): Simultaneous double parasitism by the parasitic cymothoids (Crustacea: Isopoda) of two genera on a single host fish Tenualosa toli from India. Nauplius (e 2022013) 30: 1-8, DOI: 10.1590/2358-2936e2022013, URL: https://doi.org/10.1590/2358-2936e2022013
61139E33C754196A324BFA09FA507116.taxon	materials_examined	Type species: Anilocra physodes (Linnaeus, 1758).	en	Kumar, Panakkool Thamban Aneesh Helna Ameri Kottarathil Appukuttannair Biju (2022): Simultaneous double parasitism by the parasitic cymothoids (Crustacea: Isopoda) of two genera on a single host fish Tenualosa toli from India. Nauplius (e 2022013) 30: 1-8, DOI: 10.1590/2358-2936e2022013, URL: https://doi.org/10.1590/2358-2936e2022013
61139E33C754196B303FFE8BFE3E77BA.taxon	description	(Fig. 1 D)	en	Kumar, Panakkool Thamban Aneesh Helna Ameri Kottarathil Appukuttannair Biju (2022): Simultaneous double parasitism by the parasitic cymothoids (Crustacea: Isopoda) of two genera on a single host fish Tenualosa toli from India. Nauplius (e 2022013) 30: 1-8, DOI: 10.1590/2358-2936e2022013, URL: https://doi.org/10.1590/2358-2936e2022013
61139E33C754196B303FFE8BFE3E77BA.taxon	biology_ecology	Host. Tenualosa toli and Nematalosa nasus (Clupeidae) (Aneesh et al., 2019; 2021; Amrutha et al., 2021; present study). Distribution. Kerala coast; southwest coast of India; the Bay of Bengal and Malabar coast of Kerala, India (Aneesh et al., 2021; present study). Remarks. The body surface attaching cymothoid An. grandmaae is recently described by Aneesh et al. (2021) based on morphological and molecular characterization. This species was originally identified as An. leptosoma by Aneesh et al. (2019) and the reexamination of the materials suggested that it may not be the original An. leptosoma of Bleeker and therefore was erected as a new species. Anilocra grandmaae, can be identified by: body less than 4.0 times as long as wide; antennula article 3 anterodistal margin expanded, 1.2 – 1.4 times as wide as long; pleonite 1 visible but largely concealed by pereonite 7, lateral margin posteriorly produced; pereopods 1 – 4 with three prominent nodules on dactylus; endopod of pleopods 3 – 5 with proximomedial lobe and endopod of pleopods 3 – 5 with multiple folds; pleotelson ovate, lateral margins converging smoothly to a caudomedial point (Aneesh et al., 2021). Eventhoughthesimultaneousco-occurrenceof 2 – 5 different species of parasitic crustaceans are reported from different regions, including India, the studies on co-occurrence involving two different cymothoids were very scarce (Daniel and Premkumar, 1967; Benz et al., 2003; Rajkumar et al., 2006; Gopalakrishnan et al., 2010; Aneesh et al., 2013; 2014; Welicky and Smit, 2018). Before this study, only two valid reports are available: a recent report by Welicky and Smit (2018) from South Africa and another from the Caribbean by Williams and Bunkley-Williams (1985). Previously reported simultaneous multiple co-infestations involved one cymothoid isopod or cirriped and a copepod, or a maximum of four copepods or 2 – 5 copepods from different genera (Aneesh et al., 2014). Interestingly, the species involved in the double, triple, or quadruple parasitism exhibit site and niche specific parasitism to avoid interspecific competition (Aneesh et al., 2014). Similar observations were noted in the case of cymothoid co-infestations, which included one body surface and a branchial infesting species, or body surface and a buccal infesting species (Welicky and Smit, 2018). Similarly, the two cymothoids involved in the present study also exhibit the site and niche specific parasitization with An. grandmaae attached to the body surface and Ag. malayi settled on either side of the gill chamber (Fig. 1 A). Parasitic cymothoids exhibit a different level of oligoxenous host specificity (Smit et al., 2014; Aneesh et al., 2019). Most species are restricted to one, or a limited number of hosts (Smit et al., 2014; Aneesh et al., 2019). The toli shad, T. toli is the type host for An. grandmaae and An. malayi is also reported from the same host (Aneesh et al., 2018; 2021). The prevalence of both species confirms their specificity towards T. toli. The infestation prevalence of Ag. malayi and An. grandmaae being 13.88 % (113 out of 814) and 8.72 % (71 out of 814), respectively. The prevalence of a simultaneous co-infestation is only 1.1 % (nine out of 814). The mechanism and the reason for simultaneous co-infestation by two cymothoid genera are still unknown. Out of the seven different localities, the simultaneous co-infestation was recorded only from three nearby localities (Azhikkal, Ayyikkara, and Ponnani) along the Malabar coast, suggesting that environmental factors may have some influence on triggering the co-occurrence. Detailed studies are needed to find out the triggering mechanisms. A better understanding of the role of environmental factors and mechanisms of host-parasite interaction among cymothoids and their hosts involved in co-infestation is warranted.	en	Kumar, Panakkool Thamban Aneesh Helna Ameri Kottarathil Appukuttannair Biju (2022): Simultaneous double parasitism by the parasitic cymothoids (Crustacea: Isopoda) of two genera on a single host fish Tenualosa toli from India. Nauplius (e 2022013) 30: 1-8, DOI: 10.1590/2358-2936e2022013, URL: https://doi.org/10.1590/2358-2936e2022013
