Accepted by M. Shin: 17 Feb. 2017; published: 1 May 2017 ZOOTAXA ISSN 1175-5326 (print edition) ISSN 1175-5334 (online edition) Copyright © 2017 Magnolia Press Zootaxa 4258 (4): 375–387 http://www.mapress.com/j/zt/ Article 375 https://doi.org/10.11646/zootaxa.4258.4.5 http://zoobank.org/urn:lsid:zoobank.org:pub:655D2AA6-3D3F-40DE-BF07-40FC311D4507 Some epibiont suctorian ciliates from meiofaunal organisms of Maldivian archipelago with description of a new ciliate species KAPULI GANI MOHAMED THAMEEMUL ANSARI 1 , LORETTA GUIDI 2 , IGOR DOVGAL 3 , MARIA BALSAMO 2 & FEDERICA SEMPRUCCI 2,4 1 Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur – 741246, Nadia, West Ben- gal, India. E-mail: kgmt.ansari@gmail.com 2 Department of Biomolecular Science (DiSB), University of Urbino, 61029 Urbino, Italy. E-mail: loretta.guidi@uniurb.it; maria.balsamo@uniurb.it; federica.semprucci@uniurb.it 3 Kovalevsky Institute of Marine Biological Research RAS, 299011 Sevastopol, Russia. E-mail: dovgal-1954@mail.ru 4 Corresponding author. E-mail: federica.semprucci@uniurb.it Abstract Five species of suctorian ciliates belonging to four different genera attached to meiofaunal organisms of Maldivian archi- pelago (Suvadiva Atoll) were documented. Three rare species (Acineta sp., Thecacineta urceolata Liao & Dovgal, 2015 and Limnoricus ceter Jankowski, 1981) and one common suctorian ciliate Thecacineta calix (Schröder, 1907) are re-de- scribed from nematodes (Croconema cinctum Cobb, 1920, Desmodorella tenuispiculum Allgén, 1928 and Desmodora sp.) and harpacticoid copepod basibionts. In addition, Trophogemma colantonii n. sp. colonizing the abdomen and legs of the harpacticoid copepod Stenhelia sp. is described. The new species differs from the relative species for the less flattened cell body, the absence of both lateral bundles of tentacles and separate lateral tentacles as well as for the presence of longitu- dinal ribs along the cuticle. The data obtained in this survey give not only new important information on the taxonomy and distribution of Suctorea, but also new insights on their relationship with meiofaunal organisms in one of the most di- verse and productive marine micro-habitat of carbonate sediments. Key words: Carbonate sediments, Central Indian Ocean, Maldivian archipelago, Meiofauna, suctorians, Trophogemma col- antonii n. sp. Introduction Some suctorian ciliate epibionts were found on the cuticle of nematodes and exoskeleton of copepods collected during scientific cruises in the Maldivian archipelago. These ciliates are mainly sessile forms and the adult stage (trophont) is usually the stalked zooid. The presence of one or more tentacles is characteristic of this group. Suctorians can be found in all types of water bodies on a wide diversity of hosts and substrates (Fernandez- Leborans & Tato-Porto 2000a). The majority of them are epibionts of various invertebrates or, in a less extent, vertebrates (fishes or turtles) (Dovgal 2002, 2013). The epibiosis phenomenon has been documented on several meiofaunal basibionts (e.g. nematodes, copepods, ostracods, halacarids and tanaidaceans) across the world oceans, and frequently in Indian Ocean (e.g. Allgén 1955; Fernandez-Leborans & Tato-Porto 2000a, b; Gelmboldt & Dovgal 2005; Dovgal et al. 2008a,b, 2009a,b; Ingole et al. 2010; Chatterjee et al. 2012, 2013, 2014; Fernandez- Leborans et al. 2012; Bhattacharjee 2014; Ansari & Bhadury 2016), but this is the first record in Maldives. In the present study, we describe a new species of the Suctorea of the genus Trophogemma (family Rhabdophryidae Jankowski, 1978) for which only Trophogemma poljanskyi Jankowski, 1970 was described until now. Limnoricus Jankowski, 1981 (family Paracinetidae) is another rare genus represented by only three species (Dovgal et al. 2008b), whereas Acineta Ehrenberg, 1834 (family Acinetidae) and Thecacineta Collin, 1909 (family Thecacinetidae) are among the most common genera reported as meiofaunal epibionts (Dovgal 2002; Ingole et al. 2010; Liao & Dovgal 2015). The systematic position of the species of suctorian ciliates found during this survey was defined according to Dovgal (2013).