First Report of Mononchus aquaticus (Nematoda) from West Bengal, India with An Updated Key to the Species Under the Genus Mononchus

Mononchus aquaticus Coetzee, 1968 is reported first time from West Bengal, India. The species was collected from the district South-24-Parganas (Sub division- Alipur Sadar; Block- Maheshtala), West Bengal, India in the month of October, 2006 from the potato (Solanum tuberosum L.) field. Four females were collected but no male was found. The present species is characterized by medium sized body (L=1.22–1.30 mm); buccal cavity measured as: 31.85–32.66 × 11.55–11.98 μm, large dorsal tooth occupying more than 80% of the total buccal cavity length; gonad amphidelphic; tail 4.09–4.21 anal diameter long, tail elongated, clavate at the end. Three caudal glands and spinneret opening terminal, distinct caudal papillae at the tail terminus.