REVISION OF THE GENUS TYLENCHOLAIMUS DEMAN, 1876 PRODELPHIC SPECIES .3

This paper is a study of a species group belonging to the genus Tylencholaimus de Man, 1876 and with an intrincate taxonomy. The group is distinguished by the combination of the following characters: prodelphic genital system, posterior branch absent or clearly reduced (in general less than the corresponding body width long), perioral area not disc-like and low (less-than-or-equal-to 3.5 mum), anterior part of the pharynx well muscularized and expanding gradually into the basal bulb, odontostyle relatively short (less-than-or-equal-to 6 mum), and tail relatively short (less-than-or-equal-to 16 mum) and rounded conoid to hemispherical. Six species constitute this group: T. australis Yeates, 1979, T. chathami Yeates, 1979, T. ibericus sp. n., T. maritus Loof & Jairajpuri, 1968, T. micronanus Yeates, 1979 and T. nanus Thorne, 1939. Descriptions, illustrations and measurements are given for all these species.