New species Monhystera tibetica sp. n. (Nematoda, Monhysterida) from West Tibet

Abstract

A new species of free-living nematode Monhystera tibetica sp. nov. from a thermal spring in the Garuda Valley at an altitude of 4249 m in Western Tibet is described. The general morphology corresponds to the generic diagnosis. The cephalic setae are very short. In the lower part of the stoma there is a small denticle. The amphid of males is situated over the level of the denticle. The distance from the edge of the head to the denticle is about 6 μm. The amphid of females is situated above the denticle. The esophagus is dilated at the base, pseudobulbus width is 22 μm. Males have numerous precloacal supplements. From the geographically close species of M. curvicaudata Tsalolikhin, 1915 the new species is distinguished by body size, amphid position, position of the vulva and the presence of the stomal denticle. From M. wangi Wu et Hoeppli, 1929 the new species differs by the amphid position and the presence of the stromal denticle. From M. shibrui Eyualem et Coomans, 1996 the new species differs in body size and length of spicules. The taxonomic status of the species with one and two denticles is discussed. The replacement of the name Tridentulus with Tridentula is no longer relevant. The validity of the name Tridentulus Eyualem et Coomans, 1995 is maintained.