Tripylina puxianensis, Xu & Zhao & Wang & Zheng, 2013

Xu, Yu Mei, Zhao, Zeng Qi, Wang, Jian Ming & Zheng, Jing Wu, 2013, A new species of the genus Tripylina Brzeski, 1963 (Nematoda: Enoplida: Trischistomatidae) from Shanxi province, China, Zootaxa 3630 (3), pp. 561-570 : 564-569

Description of Tripylina puxianensis n. sp.

( Figs 3 , 4 )

Measurements. Table 1.

Material examined. The description presented here is based on measurements of 13 paratypes, extracted from a soil and litter mixture, 0–15 cm depth, under a poplar tree ( Populus tremula L.), HouPoHe village, Puxian county , Shanxi province, North China (111 ° 19´29.12˝ N, 36 ° 18´22.80˝ E). Collected Yu Mei Xu, 30 iii, 2012 .

Holotype: National Nematode Collection of New Zealand ( NNCNZ), slide no. 280. Female . Paratypes: 12 females. NNCNZ, slide nos. 3150–3157 .

Description. Female. Body ventrally arcuate when fixed, posterior region more curved than anterior ( Fig. 3A ). Cuticle smooth, cuticular thickness 0.6–1.5 µm at different body regions.

Head rounded, continuous with body contour. Six long and four short cephalic setae in a single whorl; six longer setae 11–14 µm long or 51–69% of head diameter, more or less arcuate and directed anteriorly; four shorter setae 4.2–6.8 µm or 20–32% of head diameter, thinner than the longer cephalic setae, more or less arcuate. Dorsal tooth conspicuous, triangular, pointing towards to ventral side, at 11–17 µm from anterior end, located 2.6–4.0 µm anterior to sub-ventral teeth ( Figs 3C , 4A ). Two sub-ventral teeth similar to dorsal tooth, triangular, pointing towards to dorsal side. Amphids cup-like, their opening 3.8–6.3 µm wide, located at 13–22 µm from anterior end of body ( Figs 3B, 3C , 4A ). Pharynx 179–228 µm long, occupying 16–18% of the body length. One ventromedian seta in cervical region, located at 47–73 µm or 23–37% of pharyngeal length from anterior end ( Figs 3E , 4A ).

Excretory pore not seen. Nerve ring 83–108 µm or 41–52% of pharyngeal length from anterior end of body. A prominent cardia, 20–27 µm long and 8.5–14 µm wide, located between the pharynx and intestine ( Fig. 4B ).

Female genital system mono-prodelphic with no post-vulval sac ( Figs 3D , 4C ). Vulva-anus distance 305–425 µm long, being 4.1–7.5 times tail length. Body diameter 36–48 µm at vulva.

Vulva simple, lips protuberant, no sclerotized pieces seen in lateral view ( Fig. 4C ). No distinct pre-rectum. Rectum length less than anal body diameter, 21–27 µm. Tail bent ventrad, a pair of subdorsal caudal setae on anterior part of tail ( Fig. 3F ). Three tandem caudal glands ( Figs 3F , 4D ), a terminal spinneret, 1.4–2.9 µm long ( Figs 3F , 4E ).

Diagnosis and relationships. Tripylina puxianensis n. sp. is characterized by having a robust body. Dorsal tooth anterior to two sub-ventral teeth, triangular, pointing towards the ventral side. Two sub-ventral teeth are similar to the dorsal tooth in shapes and sizes. One ventromedian seta in the cervical region, and one pair of subdorsal setae on tail.

The genus Tripylina contains two groups of species, one with the dorsal tooth anterior to the sub-ventral teeth and one with the dorsal tooth posterior to the sub-ventral teeth ( Table 2). Tripylina puxianensis n. sp. belongs to the first group,with T. arenicola , T. ymyensis , T. ursulae and T. ixayocensis .

Sub-ventral teeth posterior to dorsal tooth arenicola 810–1250 20–30 4.7–6.8 13.1–18.3 1.9–3.2 62–69 1 single unknown de Man, 1880; Brzeski, 1963

ursulae 780–1170 22–36 4.8–5.7 13.6–27.2 – 61–67 1 single unknown Argo & Heyns

1973;Tsalolik hin 1983

ymyensis 1015 –1056 26–29 4.9–5.1 15.7–18.8 4.7–5.2 66–67 none 7 setae Tahseen &

Nusrat, 2010

ixayocensis 1300 –1600 30–38 5.5– 6.2 15–26 2.0–3.5 59–71 2 single 1 pair Cid del Prado-

Vera et al., 2012.

puxianensis n. sp. 1048–1331 26–34 5.5–6.2 14.4–23.1 2.1–3.5 56–69 1 single 1 pair This paper

* Brzeski and Winiszewska- Ś lipiṅska (1993) stated that although a single seta on the mid-ventral line anterior to nerve ring was originally described, it could not be seen when they re-examined the specimens.

Tripylina puxianensis n. sp. differs from T. arenicola by lacking vulval sclerotized pieces (present in the latter); the relative sizes of the dorsal tooth and sub-ventral teeth(similar sizes vs dorsal tooth larger than sub-ventral teeth)and the caudal setae (one pair vs absent).

Tripylina puxianensis n. sp. differs from T. ymyensis by having a ventromedian cervical seta (absent in the latter) and in the number of caudal setae (one pair vs 7 setae including two lateral pairs).

Tripylina puxianensis n. sp. differs from T. ursulae in body length (1048–1331 vs 780–1170 µm long); distance of the cervical seta from the anterior end (47–73 vs 22–28 µm); body diameter (36–48 vs 22–28 µm), caudal setae (one pair vs absent) and the shape of the vulval lips (with protruding vs non-protruding lips).

Tripylina puxianensis n. sp. differs from T. ixayocensis in body length (1048–1331 vs 1015–1056 µm); number of ventromedian cervical seta (one vs two), and the cardia size (20–27 µm long and 8.5–14 µm wide vs 15–20 µm long and 28–35 µm wide).

Based on the SSU and LSU molecular phylogenetic studies ( Figs 1 & 2 ), T. puxianensis n. sp. from China differs from all the Tripylina species with SSU and LSU sequences available in the GenBank. When compared with the molecular data for the most closely related species ( T. tearoha from New Zealand), there are 1% (3 in 946 bp) differences for SSU, and 3% (25 in 728 bp) differences for LSU between the two species.

Etymology. Species epithet named for the type locality. Puxian is a county of Shanxi province, China.

Figures

FIGURE 1. Bayesian tree inferred from SSU gene DNA sequences. Posterior probabilities exceeding 50% are given on appropriate clades. Nematode species and GenBank numbers are listed for each taxon.

FIGURE 2. Bayesian tree inferred from LSU gene DNA sequences. Posterior probabilities exceeding 50% are given on appropriate clades. Nematode species and GenBank numbers are listed for each taxon.

FIGURE 3. Tripylina puxianensis n. sp. A: Entire body. B: Anterior body region in dorso-ventral view showing amphidial openings. C: Anterior body region in lateral view showing the dorsal tooth, sub-ventral teeth and amphid. D: Genital region. E: Pharyngeal region, showing dorsal tooth, sub-ventral teeth, amphid and one ventromedian cervical seta. F: Tail, showing setae on tail. Scale bars: A=100 µm; B, C, D, E and F=20 µm.

FIGURE 4. Tripylina puxianensis n. sp. A: Pharyngeal region, lateral view, DT=Dorsal tooth, AM=Amphid, VCS=ventromedian cervical seta. B: Cardial region (arrowed). C: Genital region. V=vulva, DE=debris in intestine. D: Tail region. E: Tail terminus. Scale bars: A, B, D =20 µm; C, E =10 µm.