Tripylina tamaki, 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 : 12-14

Tripylina tamaki sp. nov.

( Fig. 5 A–F)

Measurements. Table 2.

Material examined. Holotype: NNCNZ, slide No. 261.

Paratype: three females. NNCNZ, slide Nos 2554–2556.

Description. Female. Body ventrally arcuate when fixed ( Fig. 5 A), posterior more curved than anterior. Cuticle smooth, about 1–2 μm thick anteriorly part, distinctly layered in pharyngeal region. Maximum body diameter generally near ovary, occasionally near vulva or posterior of pharynx. Body pores small and numerous, not clear.

Head rounded, continuous with body contour ( Fig. 5 A). Labial papillae short, conical. Six long and four short cephalic setae in a single whorl; the six setae 12–13 μm long, or 54–57% of head diameter, more or less arcuate, directed anteriorly; the four short setae 6–7 μm long, thinner than the six long cephalic setae, more or less arcuate. A single ventromedian cervical seta, thin, 79–86 μm, or 39–49% of pharyngeal length, from anterior end ( Fig. 5 B). Two pairs of lateral cervical setae, one anterior and one posterior to nerve ring ( Fig. 5 C). Stoma walls thickened; dorsal tooth large, triangular; two small subventral denticles in stomatal chamber 3–4 μm anterior to dorsal tooth ( Fig. 5 B). Amphids cup-like with transverse oval opening, 17–22 μm from anterior end.

Excretory pore 99–113 μm, or 56–58% of pharyngeal length, from anterior end of body ( Fig. 5 B). Nerve ring 77–91 μm, or 44–46% of pharyngeal length, from anterior end of body. Three prominent cells at pharyngo-intestinal junction ( Fig. 5 B). More than 6 oval to fusiform ventrolateral coelomocytes each (6–9 x 23 –31 μm) in intestinal region; the first nearly circular, near pharyngo-intestinal glands, and the rest fusiform, spread between two body diameters posterior to pharyngo-intestinal glands and anus.

Female genital system mono-prodelfic, ventral to intestine, 169–250 μm long, or 18–29% of body length from vulva to flexure ( Fig. 5 D), reflexed 2/3–4/5 of the way back to vulva. Eggs present in all specimens ( Fig. 5 D). Vulva simple, without protuberant lips, pore-shaped in lateral view, weakly sclerotised pieces in the vaginal area.

No distinct prerectum. Rectum length less than of anal body diameter (21 vs 27 μm). Tail usually bent ventrad, narrowing evenly ( Fig. 5 E). One pair of subdorsal caudal setae on anterior part of tail ( Fig. 5 E). Three tandem caudal glands ( Fig. 5 E), spinneret terminal, 2–3 μm long ( Fig. 5 F).

Male. Not known.

Locality and habitat. Holotype and paratypes from soil and litter from 0–10 cm depth under a group of native tree fern Cyathea medullaris (common name: Mamaku), St Johns Bush, Auckland, New Zealand (36˚ 52.354 S, 174˚ 50.531 E). Coll. Zeng Qi Zhao, 14. iii. 2008.

Diagnosis and relationships. Tripylina tamaki sp. nov. is characterised by a single ventromedian seta and two pairs of lateral setae in the cervical region ( Fig. 5 B & C), thickened stoma walls, large triangular dorsal tooth, two small subventral denticles in stomatal chamber 3–4 μm anterior to the dorsal tooth, and cup-like amphids with transverse oval opening 17–22 μm from anterior end of body.

Females of T. tamaki sp. nov. are similar to those of T. tearoha sp. nov., T. manurewa sp. nov., T. sheri , T. arenicola and T. ursulae in body length. However, they are longer than T. macroseta and shorter than all other species ( T. longa , T. stramenti , T. yeatesi sp. nov. and T. kaikoura sp. nov.) ( Table 3).

T. tamaki sp. nov is similar to T. tearoha sp. nov., T. manurewa sp. nov., T. sheri , and T. macroseta in having two subventral denticles anterior to the dorsal tooth, but differs from T. arenicola and T. ursulae which have two subventral denticles posterior to the dorsal tooth ( Table 3).

T. tamaki sp. nov. is similar to T. manurewa sp. nov. and T. tearoha sp. nov. in having a single ventromedian seta and two pairs of lateral setae in the cervical region. It differs from T. sheri and T. macroseta which has no setae present in the cervical region ( Table 3).

T. tamaki sp. nov. differs from T. tearoha sp. nov. and T. manurewa sp. nov. in body diameter (51–60 vs 36–44 and 37–43 μm), de Man’s Index a (20–23 vs 25–30 and 24–29). It also differs from T. tearoha sp. nov. in the distance of ventromedian cervical seta from the head end (79–86 vs 62–77 μm).

Based on SSU and LSU molecular phylogenetic studies ( Figs. 1 & 2 ), T. tamaki sp. nov. is closer to T. tearoha sp. nov. than to T. manurewa sp. nov.. However, T. tamaki 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. tearoha sp. nov. by having a low posterior probabilities value support in SSU tree ( Fig. 1 ).

Etymology. Tamaki is a suburb of the city of Auckland, New Zealand where the St Johns Bush is situated. It is used here as a noun in apposition.

Remarks. St Johns Bush contains many different tree species. T. tamaki sp. nov. was isolated from two sites there. Two further collecting trips, made after T. tamaki sp. nov. was first found, failed to find more specimens.

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 5. Tripylina tamaki sp. nov. female. A: Entire body. B: Pharyngeal region, lateral, showing a 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.