Tripylina tearoha, Zhao, Zeng Qi, 2009

Zhao, Zeng Qi, 2009, A review of the genus Tripylina Brzeski, 1963 (Nematoda: Triplonchida), with descriptions of five new species from New Zealand, Zootaxa 2238, pp. 1-24 : 6-10

Tripylina tearoha sp. nov.

( Fig. 3 A–F)

Measurements. Table 2.

Material examined. Holotype: National Nematode Collection New Zealand ( NNCNZ), slide No. 259.

Paratypes: eleven females. NNCNZ, slide Nos 2535–2545.

Description. Female. Body ventrally arcuate when fixed ( Fig. 3 A), posterior more curved than anterior. Cuticle smooth, about 1–2 μm thick anteriorly, no distinct layering observed. Maximum body width generally near ovary, occasionally near vulva or base of pharynx. Body pores small and numerous, evenly distributed on both ventro-lateral and dorso-lateral aspects.

Head rounded, continuous with body contour. Labial papillae short, conical. Six long and four short cephalic setae in a single whorl; the six setae 11–13 μm long or 52–60% of head diameter, more or less arcuate and directed anteriorly; the four setae 5.0–5.8 μm long, thinner than the six long cephalic setae, more or less arcuate. A single ventromedian cervical seta, thin, located 62–77 μm, or 37–38% of pharyngeal length, from anterior end of body. Two pairs of lateral cervical setae, one anterior and one posterior to nerve ring ( Fig. 3 C). Stoma walls thickened; dorsal tooth large, triangular; two small subventral denticles in stomatal chamber 2–3 μm anterior to dorsal tooth ( Fig. 3 B). Amphids cup-like with transverse oval opening, 23–26 μm from anterior end of body ( Fig. 3 B).

Excretory pore 93–116 μm, or 49–59% of pharyngeal length, from anterior end of body ( Fig. 3 B). Nerve ring 77–91 μm, or 43–47% of pharyngeal length, from anterior end of body. Three prominent cells located at the pharyngo-intestinal junction. In intestinal region, 4–5 oval to fusiform ventro-lateral coelomocytes each 6–8 µm x 26–32 μm; the first oval shaped, near pharyngo-intestinal glands; the rest fusiform, spread almost evenly from mid-body to anus.

Female genital system mono-prodelphic, ventral or lateral to intestine, 111–183 μm long, or 11–18% of body length from vulva to point of flexure ( Fig. 3 D). Ovary reflexed 2/3–3/4 of the way back to vulva. No eggs observed. Vulva simple, without protuberant lips, pore-shaped in lateral view, no sclerotised pieces seen in vaginal area.

No distinct prerectum. Rectum slightly shorter than anal body diameter (18 vs 23 μm). Tail usually bent ventrad, narrowing evenly ( Fig. 3 E). One pair of subdorsal caudal thick, short setae on anterior part of tail ( Fig. 3 E). Three tandem caudal glands ( Fig. 3 A & E); spinneret terminal, 2–3 μm long ( Fig. 3 E & F).

Male. Not known.

TABLE 2. Morphometric data for Tripylina tearoha sp. nov., T. manurewa sp. nov., T. tamaki sp. nov, T. yeatesi sp. nov. and T. kaikou

Holotype female Paratype females (Mean ± S.D.)

(36–40) (38–44) (37–43) (61–60 (62–77) (81–95) (71–105) (74–82 Species L of female a b c c’ V % Cervical Setae on References

(µm) seta or setae tail

Subdenticles anterior to dorsal tooth Subdenticles posterior to dorsal tooth

arenicola 1035 24 5.2 17.7 2.2 69 1 single unknown de Man, 1880;

(800–1200) (23–27) (5.0–5.5) (16.8–18.7) (1.9–2.7) (67–70) Brzeski, 1963 ursulae 1050 29 5.3 17.5 - 64 no unknown Argo & Heyns (780–1170) (22–26) (4.8–5.7) (13.6–27.2) (61–67) 1973; Tsalolikhin

1983

* Brzeski & Winiszewska-Ślipińska (1993) stated that although a single seta on the midventral line anterior to nerve ring was originally described, a ventral cervical seta could not be seen when they re-examined the specimens.

Locality and habitat. Holotype and seven paratypes (slide nos 2535–2541) from soil and litter mixture, 0–10 cm depth under a Pinus radiata tree, Te Aroha Domain, Thames Valley region, New Zealand (37º 32.165 S, 175º 42.911 E). Coll. Zeng Qi Zhao, 7. xi. 2007; four paratypes (slide nos 2542–2545) from soil, 0–10 cm depth under a native Dacrycarpus dacrydioides tree (common names: Kahikatea, white pine) surrounded by several Geniostoma ligustrifolium trees, Smith’s Bush, North Shore City, Auckland, New Zealand (36º 48.782 S, 174º 45.026 E), Coll. Zeng Qi Zhao, 4. iv. 2008.

Diagnosis and relationships. Tripylina tearoha sp. nov. is characterised by having a single ventromedian cervical seta and two pairs of lateral cervical setae ( Fig. 3 B & C).

Females of T. tearoha sp. nov. are similar in total body length to T. manurewa sp. nov., T. tamaki sp. nov., T. sheri Brzeski, 1963 , T. arenicola (de Man, 1880) Brzeski, 1963, T. ursulae ( Argo & Heyns, 1973) Tsalolikhin, 1983 ; they are longer than T. macroseta ( Vinciguerra & La Fauci, 1978) Tsalolikhin, 1983 and shorter than all other species ( T. longa Brzeski & Winiszewska-Ślipińska, 1993 , T. stramenti ( Yeates, 1972) Tsalolikhin, 1983 , T. yeatesi sp. nov. and T. kaikoura sp. nov. ( Table 3).

The genus of Tripylina contains two groups of species, one with subventral denticles anterior to the dorsal tooth, and one with them posterior ( Table 3). T. tearoha sp. nov. belongs to the first group, with T. manurewa sp. nov., T. tamaki sp. nov., T. sheri , T. macroseta , T. longa , T. stramenti , T. yeatesi sp. nov., and T. kaikoura sp. nov..

T. tearoha sp. nov. is closest to T. manurewa sp. nov., T. tamaki sp. nov in that all have a single ventromedian seta and two pairs of lateral setae present in the cervical region. It differs from T. sheri and T. macroseta which lacks setae in the cervical region ( Table 3).

T. tearoha sp. nov. differs from T. tamaki sp. nov. in body diameter (36–44 vs 61–60 μm), de Man’s Index a (25–30 vs 20–23) and differs from T. manurewa sp. nov. by in the distance of ventromedian cervical seta from the anterior end of the body (62–77 vs 78–86 μm).

Based on the SSU and LSU molecular phylogenetic studies ( Fig. 1 & 2 ), T. tearoha sp. nov. is genetically closer to T. tamaki sp. nov. than to T. manurewa sp. nov.. However, T. tearoha sp. nov. is clearly different from T. manurewa sp. nov. from both SSU and LSU trees, in which they were not in one clade, and different from T. tamaki sp. nov. by having a low posterior probabilities value support in SSU tree. Females of T. tearoha sp. nov. from Te Aroha and Smith’s Bush show slight morphological differences but could not be distinguished using molecular techniques.

Etymology. The name ‘Te Aroha’ comes from the Maori name of the Mount Te Aroha. It is used here as a noun in apposition.

Figures

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

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

FIGURE 3. Tripylina tearoha sp. nov. female. A: Entire body. B: Pharyngeal region, lateral, showing the single cervical seta. C: Pharyngeal region, ventral, showing two pairs cervical setae. D: Genital region, lateral. E: Tail. F: Spinneret. Scale bars: A, B, C, D, E = 50 μm; F = 25 μm.