Review of Euchromadorinae (Nematoda: Chromadorida) with description of a new species of Trochamus Boucher & De Bovée, 1971 from the Sundarban, India Author Datta, Tridip Kumar ENVIS Centre, Zoological Survey of India, M-Block, New Alipore, Kolkata- 700053, India. Author Al-Helal, Md. Abdullah Vidyasagar University, Department of Zoology, Paschim Medinipur, Midnapore- 721102, West Bengal, India. text Zootaxa 2023 2023-05-08 5278 3 493 510 http://dx.doi.org/10.11646/zootaxa.5278.3.4 journal article 10.11646/zootaxa.5278.3.4 66cdc377-c9b8-476a-9cc1-d504e654b52a 1175-5326 7906615 5B09ECEE-2A61-411F-A172-5FD86939905F Actinonema Cobb, 1920 (emended after Venekey et al. 2019 & Tchesunov 2014 ) Cuticle complex, heterogeneous with lateral differentiation as a ridge begins at the end of the pharynx. Six outer labial and four cephalic setae arranged in one circle. Amphideal fovea conspicuous, transversally oval with a double contour. Posterior pharyngeal bulb may develop. Buccal cavity with one prominent dorsal tooth and two small subventral teeth. Spicules simple, thickly cuticularized. Gubernaculum with L-shaped lateral piece. A cuticularized tube may run in between each spicule and gubernaculum. Type species: A. pachydermatum Cobb, 1920 List of valid species: A. celtica Boucher, 1976 A. falciforme Shi, Yu & Xu, 2018 A. fidatum Vitiello, 1970 A. grafi Jensen, 1991 A. longicaudatum ( Steiner, 1918 ) Wieser, 1954 A. pachydermatum Cobb, 1920 A. paraceltica Muthumbi & Vincx, 1998a A. smolae Muthumbi & Vincx, 1998a Taxon inquirendum: A. chitwoodi Wieser, 1954