Redescription of Tanqua tiara (von Linstow, 1879) Blanchard, 1904 (Nematoda: Gnathostomatidae) from Varanus flavescens (Hardwicke and Gray, 1827) (Reptilia: Varanidae) from Birbhum district, West Bengal, India.

Tanqua tiara (von Linstow, 1879) Blanchard, 1904, recovered from the stomach of water monitor lizard, Varanus flavescens (Hardwicke and Gray, 1827), collected from the Dubrajpur town, Birbhum district of West Bengal, India, is redescribed with light as well as scanning electron microscopy. This species is characterised by presence of two large lateral pseudolabia followed by massive cephalic bulb. The inner surface of each pseudolabium is folded into five rounded tooth-like formations which fit into corresponding folds on adjacent pseudolabium. Spicules are equal and similar. Gubernaculum is absent. Caudal papillae are sessile and five pairs in number. Present nematode differs from earlier descriptions of T. tiara in having five pairs of caudal papillae and an unpaired median precloacal papilla. Position of phasmids has also been reported in present study. Actual structure of cervical papillae and cuticular striations have been shown in present SEM studies which are also different from earlier descriptions. Dubrajpur is recorded as new geographical area for this parasite. © Indian Society for Parasitology 2020.