A REVISION OF THE GENUS PSEUDACROBELES STEINER, 1938 (NEMATODA, CEPHALOBIDAE) .1. SUBGENUS PSEUDACROBELES GRAD-N

Major changes are proposed to the composition of the genus Pseudacrobe les on the basis of numerous specimens from several species, mainly fr om tropical and subtropical countries. In the first part of this revis ion, the diagnosis of the genus is emended. The subgenus Pseudacrobele s grad. n. is proposed, characterized by the occurrence of labial prob olae in all its species, and of cephalic probolae in some. The genus P anagrocephalus is considered a junior synonym of genus and subgenus Ps eudacrobeles; Panagrocephalus anadelphus and P. baloghi are transferre d, and P. anadelphus impervius is synonymized with P. baloghi. The gen us Heterocephalobus is considered genus inquirendum because of its uns atisfactory diagnostic characters. Heterocephalobus laevis, H. paucian nulatus, H. tabacum and H. teres are transferred to genus and subgenus Pseudacrobeles. The type species of the genus and subgenus, Pseudacro beles (P.) variabilis, was found to be part of a very variable group w hich could not be divided easily but did appear to represent several s pecies. The superspecies P. (P.) [variabilis] is proposed for this gro up, comprising of the species P. (P.) [v.] baloghi, P. (P.) [v.] macro cystis, P. (P.) [v.] tabacum and P. (P.) [v.] variabilis. Intraspecifi c variability of the lip region in P. (P.) [v.] variabilis is shown as seen with SEM.