Paranticoma tricerviseta Zhang, 2005

Hong, Jung-Ho, Kim, Kichoon & Lee, Seunghan Lee and Kanghyun, 2024, Four unrecorded species of free-living nematodes from the sublittoral zone in the East Sea, Korea, Journal of Species Research 13 (2), pp. 147-158 : 148-150

Paranticoma tricerviseta Zhang, 2005 ( Fig. 1 , Table 1)

Locality. The coast of Gijang: subtidal southern part of the East Sea, Korea (35°16 ʹ 0.0 ʺ N, 129°16 ʹ 50.0 ʺ E), at a depth of 16 m, in the clay sediment .

Material. Four males ( MABIK NA00158060 , MABIK NA00158086 - MABIK NA00158088 ) and three females ( MABIK NA00158089 - MABIK NA00158091 ) were collected by Jung-Ho Hong at the coast of Gijang on 30 April 2023, from the Research Vessel Haeyanghwnangkyung 3 .

Measurements. See Table 1 for detailed measurements and morphometric ratios.

Description. Males ( Fig. 1 , Table 1). Body cylindrical, gradually tapering toward both extremities with anterior body end strongly narrowed. Cuticle smooth, with short and scattered somatic setae. Tail conico-cylindrical. Six small, rounded labial papillae. Six longer cephalic setae arranged in one circle measuring 8-9 μm (about 53.3- 60.0 of head diameter). Three short cervical setae (about 2 μm) situated laterally, on both sides of body located 45-52 μm from anterior body end. Buccal cavity small, conical shape with three indistinct, weakly sclerotized, tooth-like pieces. Amphidial fovea cup-shaped, indistinct measuring 4-5 μm in width (28.6-31.3% of cbd, with opening slightly behind a circle of cephalic setae. Pharynx relatively long (485-580 μm), muscular, slightly broad- ened at its base (48-59% of cbd). Cardia small. Excretory pore located on seta-like projection of cuticle situated 18- 23 μm from anterior body end. Renette not observed. One testis, located to left of intestine. Two thin, curved spicules (42-50 μm) with ventral side projection measuring 1.2- 1.3 times as long as cloacal body diameter. Gubernaculum 16-22 μm long, no apophyses. Precloacal supplements absent. Tail consists of proximal conical and distal cylindrical parts, with latter comprising 60-66% of tail length and featuring somatic setae. Caudal glands and spinneret well-developed. Two pairs of postanal subventral setae, each measuring 4-5 μm in length and located 60- 69 μm from anus.

Females ( Fig. 1 , Table 1). Similar to male. Reproductive system didelphic, amphidelphic. Ovaries situated to left of intestine, reflexed and comparatively short. Vulva situated slightly posterior to mid-body, at 51.9-54.1% of body length.

Remarks. To date, the genus Paranticoma Micoletzky, 1930 contains 10 valid species: P. antarctica Mawson, 1956 ; P. bandaense Micoletzky, 1930 ; P. calidomensis Inglis, 1967 ; P. elegans Micoletzky, 1930 ; P. lepta Phan Ke Long, Nguyen Dinh Tu & Gagarin, 2019 ; P. odhneri Allgén, 1959 ; P. profunda Micoletzky, 1930 ; P. tenuis Allgén, 1947 ; P. tricerviseta Zhang, 2005 ; P. tubulifora Wieser, 1953 ( Nemys, 2023). The specimens from the East Sea, Korea, generally conform to the original description by Zhang (2005), with minor variations observed in body width (45-59 μm compared to 57-82 μm), body length (1902-2282 μm compared to 2472-3300 μm), and spicule length (42-50 μm compared to 47-62 μm). We interpret this variation as intraspecific diversity.

Figures

Fig. 1. Paranticoma tricerviseta Zhang, 2005, from the East Sea, Korea. A, Male head; B, Female vulva and tail; C, Male precloacal and anal region. Scale bars: 20μm (A, C) and 500 μm (B).