垫刃属线虫2新种描述(线虫门:垫刃科)

DESCRIPTION OF THE NEW SPECIES OF GENUS Tylenchus (BASTIAN, 1865) (NEMATODA TYLENCHIDAE)

小垫刃线虫新种(Tylenchus minor n.sp.)和拟小垫刃线虫新种(T.paraminor n.sp)分别采集于广东省宝安县的葱(Allium fistulosum)和柑(Citrus reticulata)根际土壤。两者以中食道球位置较前、排泄孔位置较后和无明显后阴子宫囊等特征区别于近似种新最小垫刃线虫(T.neominimus Savkina,Savkina,1989);以角质层有环纹和口针较长等特征区别于另一近似种微针垫刃线虫(T.stylolus Xie et Feng,1995)。2新种在体长、口针长和无明显后阴子宫囊等特征上非常近似,但后者以阴门位置较后、尾短并且小于或等于肛阴距等特征明显区别于前者。

Tylenchus minor n. sp. and Tylenchus paraminor n. sp. were described in this paper. T. minor n. sp. was found from the rhizosphere soil of Allium fistulosum in Guangdong, China. Having smaller body size (L=409±35.6 (356～520) μm), shorter stylet (9.8±0.61 (7.8～10.4) μm) and finer body annulation, the new species was closely related to T. neominimus Savkina, 1987. It differed from T. neominimus by more anteriorly located metaeorpus [MB=45±2.4 (39～48) ], excretory pore at the level of anterior end of esophageal glands, more anterior position of vulva [V= 63±1.3 (61～66)1, oocytes arranged in a single file, post vulval uterine sac not obvious or absent, tail terminus rounded smooth, spicules longer (17 μm) and bursa shorter [14.3 (13.0～15.6) μm]. In T. neominimus, MB=50; excretory pore at the level of middle of isthmus; V = 67 (66～69); oocytes arranged in one to two files; post vulval uterine sac obvious; tail terminus pointed, spicules 13 μm long; bursa 20 μm long. Because of smaller body size and post vulval uterine sac not obvious or absent, the new species should also be compared with T. stylolus Xie & Feng, 1995. The two species differed by cuticle with annulation, styler = 9.8±0.61 (7.8～10.4) μm, more anterior position of vulva, tail longer [84±7.8 (73～100) μm] and almost equal width near terminus with rounded smooth and male known in former (in T. stylolus, cuticle without annulation, stylet=6.4±0.22 (6.0～ 6.5) μm, V=67±2.0 (64～70), tail=70±4.4 (62～74) μm, tail slender conoid with buntly pointed tip, male unknown). Tylenchus paraminor n. sp. from the rhizosphere soil of Citrus reticulate in Guangdong, China was most closely related to T. minor n. sp. by cuticle with annulaiton, body length [448±32.9 (377～520) μm], styler length [9.2±1.1 (7.8～10.4) μm], position of metacorpus, and excretory pore, oocytes arranged in a single file and post vulval uterine sac not obvious or absent. The two species differed by more posterior position of vulva [V=69±2.7 (66～74)], vagina shorter than 1/2 of body width at vulva, greater c valua [c= 7.4±0.91 (6.2～8.9) ], tail 61.6±7.9 (46.8～70.2) μm long and shorter than or as long as vulva-anus distance, tail tip pointed or bluntly pointed in former ( T. minor n. sp. has V = 63±1.3 (61～66), vagina longer than 1/2 of body width at vulva, c= 4.9±0.41 (4.3～5.8), tail 84±7.8 (73～100) μm long and longer than vulva-anus distance, tail tip rounded smooth). T.paraminor n. sp. was closely related to T. neominimus in body length, stylet length and cuticle with annulation and to T. stylolus in body length and post vulval uterine sac not obvious or absent. The new species differed from the former by more anterior position of metacorpus [MB=42.5±2.1 (39.1～44.1 )], excretory pore at the level of anterior end of esophageal glands, cocytes arranged in a single file and post vulval uterine sac not obvious, from the latter by cuticle with annulation, stylet=9.2±1.1 (7.8～10.4) μm, c=7.4±0.91 (6.2～8.9), c'=7.9±1.2 (5.9～9.6), tail shorter than or as long as vulva-anus distance. In T. stylolus, c=5.5±0.28 (5.2～5.8), c' = 10.8±2.1 (9.2～14.3), tail longer than vulva-anus distance. Type specimens are deposited in the Plant Nematology Laboratory, South China Agricultural University, Gangzhou, China.