Detailed morphology of a new diplogastrid and a known ektaphelenchid species isolated from Simao pine in south-western China were illustrated and described/redescribed. Micoletzkya chinaae n. sp. is characterized by a relatively short body length (601-802 μm in female and 505-773 μm in male), undivided cheilorhabdia (forming an entire ring), dimorphic buccal cavity (eury- or stenostomatous), a large claw-like dorsal tooth and a large right subventral tooth in the stoma of eurystomatous form, typical diplogastrid pharynx, didelphic female gonads, nine pairs of genital papillae on male tail region with two ventral pairs (GP1 and GP2) closely associated, a unique gubernaculum morphology, and a long filiform tail in both sexes. The new diplogastrid belongs to the Group 1 category of Micoletzkya species sensuMassey, 1966, which is characterized by stoma equipped with a large dorsal and a large subventral tooth, and both teeth can cross near the center of the pharynx. The new species can be easily distinguished from other species within this group except for M. tomeaMassey, 1966 with the long filiform female and male tails. However, it shows great similarities to Mononchoides spp., Koerneria spp., Fictor spp., and Acrostichus members in some aspects. More morphological features as well as molecular data of this clade should be available before relationships between and within these genera can be better interpreted. The two large moveable teeth in eurystomatous worms indicate their potentially predacious habits, and re-isolation of this species is necessary. Morphology of south-western Chinese population of Ektaphelenchus macrobulbosus (Rühm,1956) Massey, 1974 conforms well to the previous descriptions except for a few minor variations. It is characterized by medium-long female and male bodies (676-791 and 613-685 μm, respectively), three incisures in the lateral field, offset cephalic region, knobless stylet 18-20 μm long, oblong median bulb with posteriorly situated valves, two to three rows of developing oocytes, short postuterine sac, absence of female rectum and anus, two pairs of subventral papillae on the male tail region, a cucullus (apophysis) present on the dorsal distal end of the spicule, and the conoid female and male tails.
Keywords: Ektaphelenchus; Micoletzkya; Pinus kesiya var. langbianensis; SEM; description; morphology; morphometrics; new species; pine wood nematode; redescription; taxonomy.