Some studies on Tylenchorhynchinae: proposal ofDivittus n.g. (Nematoda: Tylenchida)

Summary A new genusDivittus is proposed in the subfamily Tylenchorhynchinae Eliava, 1964 with only three incisures in the non-areolated lateral fields and the body cuticle without longitudinal ridges or lamellae. It is also proposed to restrictTrilineellus Lewis & Golden, 1981 to its type species only, i.e.,T. clathrocutis which has three incisures in the lateral fields and longitudinal ridges or lamellae on the body, andTylenchorhynchus to species which have four incisures in the lateral fields but no ridges or lammellae.T. divittatus Siddiqi, 1961,T. triglyphus Seinhorst, 1963 andT. sculptus Seinhorst, 1963 which were transferred toTrilineellus by Lewis & Golden (1981) are now included inDivittus with the following species ofTylenchorhynchus which have three incisures in the lateral fields:T. obscurisulcatus Andrássy, 1959,T. chonai Sethi & Swarup, 1968,T. madrasensis Gupta & Uma, 1981 andT. pruni Gupta & Uma, 1981. The synonymy ofT. chonai withT. triglyphus proposed by Tarjan (1973) is not accepted.Divittus labiatus n.sp. from soil around roots of sugarcane from north-eastern Nigeria is described. It is characterized by having the lip region continuous with the body, the spear 14–16 m long, the basal oesophageal bulb with a small overlap over the intestine and the tail with a large post-anal intestinal sac and 20 to 30 annules. A key to species ofDivittus is provided. ac]19830105