Revision of the genus Tylencholaimus de Man, 1876 prodelphic species .4

The present paper deals with the taxonomy of a species group belonging to the genus Tylencholaimus de Man, 1876 and characterized by the following set of features: prodelphic female genital system, posterior branch absent or clearly reduced (always shorter than the corresponding body width), perioral area not disc-like and relatively high (greater than or equal to 4 mu m), anterior part of the pharynx well muscularized and expanding gradually to the basal bulb, odontostyle relatively long (greater than or equal to 6 mu m), and tail relatively long (over or equal to 16 mu m) and convex-conoid to conical with rounded terminus. Six species constitute the group: T. americanus n. sp., T. cedari (Siddiqi & Khan, 1964) Jairajpuri & Ahmad, 1992, T. notrus Khan, Jairajpuri Br Ahmad, 1990, T. obscurus Jairajpuri, 1965, T. proximus Thorne, 1939 and T. terrestris n. sp. T. dorae Kruger, 1965 is considered a junior synomym of T. obscurus. Descriptions, illustrations and measurements are given for all of these species.