Tripylina yeatesi, 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 : 14-16

Tripylina yeatesi sp. nov.

( Fig. 6 A–D)

Measurements. Table 2.

Material examined. Holotype: NNCNZ, slide No. 262.

Paratype: NNCNZ, slide No. 2557.

Descriptions. Female. Body ventrally arcuate when fixed ( Fig. 6 A), posterior more curved than anterior. Cuticle smooth, about 1–1.5 μm thick anteriorly, without distinct layering. Maximum body diameter near vulva. Body pores present but obscure.

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 43– 47% of head diameter, more or less arcuate, directed anteriorly; the four setae 6–7 μm long, thinner than the six long cephalic setae, more or less arcuate. No setae in cervical region. Stoma walls thick; dorsal tooth large, triangular; two small subventral denticles in stomatal chamber 3–4 μm anterior to dorsal tooth. Amphids cup-like with transverse oval opening, 17–21 μm from anterior end of body.

Excretory pore 114–118 μm, or 45 % of pharyngeal length, from anterior end of body ( Fig. 6 C). Nerve ring 114–116 μm, or 44–46% of pharyngeal length, from anterior end of body ( Fig. 6 B). Three prominent cells at the pharyngo-intestinal junction. Four oval to fusiform ventrolateral or lateral coelomocytes, each 10– 12 x 42 –57 μm; the first oval, 16 x 31 μm, near pharyngo-intestinal glands; the rest fusiform, spread from middle body to anus, one normally near tip of gonad, two between vulva and anus.

Female genital system mono-prodelphic, ventral to intestine, 276–357 μm long, or 19–23% of total body length from vulva to point of flexure ( Fig. 6 C), reflexed to vulva. Eggs present ( Fig. 6 A). Vulva simple, without protuberant lips, pore-shaped in lateral view, slightly sclerotised pieces in vaginal area.

No distinct prerectum. Rectum length less than anal body diameter (21 vs 31 μm). Tail usually bent ventrad, narrowing evenly. No caudal setae. Three tandem caudal glands, spinneret terminal, 2.5 μm long ( Fig. 6 D).

Male. Not found.

Locality and habitat. Holotype and paratype collected from litter samples from native forest Bruce Park, Hunterville, New Zealand (39˚ 57.650 S, 175˚ 31.726 E). Coll. Gregor W. Yeates, 12. vi. 1989. Diagnosis and relationships. Tripylina yeatesi sp. nov. is characterised by its long body, absence of ventromedian setae in the cervical region, thickened stomatal walls, large triangular dorsal tooth, two small subventral denticles in stomatal chamber 3.5–4 μm anterior to the dorsal tooth, and cup-like amphids with transverse oval opening, located 17–21 μm from the anterior end of the body.

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

T. yeatesi sp. nov. is similar to T. longa , T. stramenti and T. kaikoura sp. nov. in having two subventral denticles anterior to dorsal tooth. It differs from T. arenicola and T. ursulae which have two subventral denticles posterior to dorsal tooth ( Table 3).

T. yeatesi sp. nov. is similar to T. kaikoura sp. nov. in lacking a ventromedian seta and setae in the cervical region, but differs from T. longa which has two cervical setae and T. stramenti which has one cervical seta ( Table 3).

T. yeatesi sp. nov. differs from T. kaikoura sp. nov. in having a narrower body (49–55 vs 68–71 µm) and different de Man’s Indices a (29–30 vs 22–23), b (5.8–6.0 vs 6.0–6.2), c (18–26 vs 14–16) and c’ (2.0–2.6 vs 2.7–3.0), respectively ( Table 3).

Etymology. I have named the species T. yeatesi sp. nov. in honour of the great nematologist and zoologist Dr Gregor W. Yeates, Landcare Research, New Zealand.

Figures

FIGURE 6. Tripylina yeatesi sp. nov. female. A: Entire body. B: Pharyngeal region, lateral. C: Genital region, lateral. D: Spinneret. Scale bars: A, B, C = 50 μm; D = 25 μm.