Tripylina zhejiangensis, Pham & Wang & Zhao & Zheng, 2013

Pham, Thi Hoa, Wang, Hai Tao, Zhao, Zeng Qi & Zheng, Jing Wu, 2013, A new species of the genus Tripylina Brzeski, 1963 (Nematoda: Enoplida: Trischistomatidae) from Zhejiang Province, eastern China, Zootaxa 3717 (2), pp. 158-168 : 160-166

Description of Tripylina zhejiangensis n. sp.

( Figs 1–4 )

Measurements. Table 1.

Type habitat and locality. The samples were collected at the Zijingang campus, Zhejiang University, Hangzhou, China. Tripylina zhejiangensis n. sp. was isolated from the rhizospheres of bamboo ( Bambusa multiplex ) at 30 ° 18.00 N, 120 ° 04.770E, paper mulberry ( Broussonetia papyrifera ) at 30 ° 18.52 N, 120 ° 04.901 E, and willow ( Salix babylonica ) at 30 ° 18.097 N, 120 ° 04.778 E.

Material examined. Holotype. Female. Slide No. TNG828 was deposited at the Nematology laboratory, Zhejiang University, Hangzhou, China.

Paratypes. Slides No. TJN830, TNG829 , TR10131 , TR10132.1 with 6 females were deposited at the National Nematode Collection of New Zealand . Slides No. TNG820-827, TR10120-10129 , TR10133-10139 , TR1002 , TNG801 including 35 females and 28 juveniles were deposited at the Nematology Laboratory of Zhejiang University, Hangzhou, China .

Description. Females. Body ventrally arcuate after gentle heating, moderately large, robust, posterior region more curved than anterior ( Figs 1A , 3A, B, C , 4D ). Cuticle not striated, with numerous body pores along entire body. Six long (11–16 µm) and four short cephalic setae (4–7µm) in a single whorl ( Figs 3A, B, C ).

Head rounded, continuous, 24 µm diam. ( Figs 1B , 4A, B ). Lip region dome-shaped, three triangular lips visible with SEM; 19–25 µm diam., inner labial papillae conical, outer labial setae ( Fig. 3A, B, C ). Thick stomatal walls, with a large triangular dorsal tooth in a stomatal chamber, pointing towards ventral side. Two triangular subventral teeth located posterior to dorsal tooth ( Figs 1F, J , 4B ). Amphids cup-like, located at 12–17µm from anterior end. A ventromedian seta in cervical region, located at 77–95 µm or 31–32% of pharyngeal length from anterior end ( Figs 1E , 4A ).

Excretory pore not observed. Nerve ring 99–139 µm or 44–51% of pharyngeal length from anterior end of body. A prominent cardia separates the pharynx and intestine, 20–27 µm long and 8.5–14 µm wide ( Fig. 1G ). Pharyngo-intestinal valve composed of three glands around anterior portion of intestine. An ingested nematode was observed within the intestine of one specimen of this species ( Fig. 2 ).

Female genital system mono-prodelphic without post-vulval sac. Vulva simple, lacking protuberant lips ( Figs 1C , 4E ). Tail bent ventrad, a pair of subdorsal caudal setae on anterior part of tail, three tandem caudal glands, a terminal spinneret, 2–4 µm long ( Figs 1D , 3D , 4C ).

Males: not found.

Juveniles: all characteristics similar to those of females except for size and lack of a mature reproductive system.

Diagnosis and relationships. Tripylina zhejiangensis n. sp. is characterized by having a robust body, a large dorsal tooth, two sub-ventral teeth triangular posterior to dorsal tooth, and one ventromedian seta in the cervical region.

Species in the genus Tripylina are divided into two groups ( Zhao 2009), one with the dorsal tooth anterior to the sub-ventral teeth and one with the dorsal tooth posterior to the sub-ventral teeth. Tripylina zhejiangensis n. sp. belongs to the first group with T. ymyensis , T. puxianensis , T. ursulae , T. ixayocensis and T. arenicola .

Tripylina zhejiangensis n. sp. differs from T. ymyensis in having a longer body length (1325–1573 vs 1015– 1056 µm), longer tail length (75–103 vs 55–60 µm), a ventromedian cervical setae (one vs none), and fewer caudal setae (one vs seven). Tripylina zhejiangensis differs from T. puxianensis in body length (1325–1573 vs 1048–1331 µm), tail length (75–103 vs 53–85 µm), and vulva without protuberant tips vs with protuberant tips.

Tripylina zhejiangensis n. sp. resembles T. ursulae in the values of De Man’s Indices (a, c and V) but differs in having a longer body length (1325–1573 vs 780–1170 µm); and greater body diameter (47–66 vs 22–28 µm). Tripylina zhejiangensis n. sp. differs from T. arenicola in body length (1325–1573 vs 810–1250 µm) and in lacking vulval sclerotized pieces (present in the latter).

Tripylina zhejiangensis n. sp. differs from T. ixayocensis by having non-protuberant vulval lips vs with protuberant lips, tail length (74–103 vs 42–94 µm), and the presence of body pores (absent in the latter).

Etymology. Species name “ zhejiang ” refers to the name of Zhejiang province from where samples were collected.

Molecular phylogenetic analyses. No significant difference was found in the sequences of T. zhejiangensis from three populations. Phylogenetic analysis revealed that T. zhejiangensis n. sp. is different from other sequenced species ( Figs 5 , 6 ). With regard to the other two Tripylina species from China, sequences of T. zhejiangensis had 92.9% and 93.9% similarity to T. puxianensis for SSU and D2/D3 region expansion segments of LSU of rDNA, respectively. No molecular data is available for T. ymyensis ( Tahseen & Nusrat 2010) . Further, T. zhejiangensis n. sp. is close to T. tamaki and T. tearoha (having 94.5%, 94.7% similarity). In comparison with other Tripylina species available in Genbank, the sequences of T. zhejiangensis n. sp. differ from other populations in the Tripylina genus ( Fig. 5 ).

Figures

FIGURE 1. Female of Tripylina zhejiangensis n. sp. A: Entire body. B: Pharynx region. C: Reproductive region. D: Tail. E: Anterior body region (ventro-median seta indicated by arrow). F: Head. G: Cardia. H–J: Heads.

FIGURE 2. A large portion of ingested nematode within intestine of a specimen of Tripylina zhejiangensis.

FIGURE 3. SEM photos of Tripylina zhejiangensis n. sp. A–B: En-face view. C: Head region. D: Tail. (Scale bars: A = 20µm, B = 10µm, C–D = 30µm)

FIGURE 4. Tripylina zhejiangensis n. sp. A: Pharynx region. B: Head. C: Tail. D: Entire body. E: Female reproductive system. (Scale bars = 20 µm)

FIGURE 5. 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 6. 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.