ORIGINAL PAPER Redescription of Nerocila recurvispina Schiödte and Meinert 1881: (Crustacea: isopoda) from the Hooghly River, Kolkata, India Panakkool-Thamban Aneesh 1 & Kandasamy Valarmathi 2 & Santanu Mitra 2 Received: 2 March 2017 /Revised: 18 September 2017 /Accepted: 18 September 2017 # Senckenberg Gesellschaft für Naturforschung and Springer-Verlag GmbH Germany 2017 Abstract Nerocila recurvispina Schiödte and Meinert, 1881, a poorly known parasitic cymothoid species, is redescribed after 134 years from materials available in the National Zoological Collections of Zoological Survey of India (NZC- ZSI) collected from Hooghly River, Kolkatta. The general morphology and appendages of various life cycle stages (male, transitional, ovigerous female and juvenile) of the spe- cies are here discussed. Important characters to distinguish N. recurvispina from other species in the genus include: coxae and postero-lateral angles of all pereonites produced into nar- row, apically pointed, acute and upwardly directed recurved spines; increasing the length of the recurved spines progres- sively from pereonite 1 to 7. Uropod rami, exopod slender, slightly longer than endopod, distal end narrowly rounded; endopod distally broader and lancelate. Keywords Cymothoid parasite . Female . Male . Transitional . Juvenile . India Introduction Cymothoids are ectoparasites of teleost fishes that inhabit di- verse aquatic ecosystems. These parasites generate an exten- sive interest among parasitologists as they affect both wild and cultured fishes (Brusca 1981; Seng and Seng 1990; Trilles 1994; Trilles et al. 2011, 2013; Aneesh et al. 2013, 2016). They are known to occur on skin, fins, buccal or branchial cavities, or burrowing into the flesh of the host fish (Smit et al. 2014). Species in genera Anilocra Leach 1818, Creniola Bruce 1987a, Pleopodias Richardson 1910 and Nerocila Leach 1818 are usually attached on the body surface; Cymothoa Fabricius 1793, Ceratothoa Dana 1852 and Glossobius Schiödte and Meinert 1883 species are found in the buccal cavity; the species from the genera such as Agarna Schiödte and Meinert 1884, Joryma Bowman and Tareen 1983, Norileca Bruce, 1990 and Mothocya Costa in Hope 1851 prefer the branchial cavities; the species of Ichthyoxenus Herklots 1870 and Riggia Szidat 1948 usually burrow into the host flesh (Schiödte and Meinert 1883, 1884; Bowman and Tareen 1983; Bruce 1986, 1987a, 1987b; Tsai and Dai 1999; Thatcher et al. 2002; Hadfield et al. 2013, 2014; Martin et al. 2015a, b, 2016; Aneesh et al. 2015, 2016; Bruce et al. 2016; Hadfield and Smit 2017). Information on parasitic crustaceans from certain regions of the world is available, particularly from America (Williams and Bunkley-Williams 1994; Brusca 1981), Australia (Bruce 1987a, b; Martin et al. 2015b, 2016), China (Yu and Li 2002, 2003), Europe (Trilles 1994; Horton and Okamura 2001), Kuwait (Bowman and Tareen 1983), Malaysia (Seng and Seng 1990), Philippines (Yamauchi et al. 2005), South Africa (Hadfield et al. 2013 , 2014 ), South America (Thatcher et al. 2003, 2007) and Singapore (Bruce et al. 2016). Despite the following reports on cymothoids from India (Pillai 1964; Rameshkumar et al. 2011; Trilles et al. Communicated by S. S. M. Kaiser * Kandasamy Valarmathi anee3716@gmail.com 1 Zoological Survey of India (ZSI), Ministry of Environment & Forests, Govt. of India, M Block, New Alipore Kolkata-700 053, Kolkata, West Bengal, India 2 Zoological Survey of India (ZSI), Ministry of Environment & Forests, Govt. of India, Fire Proof Spirit Building, 27, J. L. Nehru Road, Kolkata, West Bengal 00016, India Mar Biodiv DOI 10.1007/s12526-017-0799-8