Leptolaimus boucheri, Geng & Hao & Huang, 2022

Geng, C. X., Hao, Y. D. & Huang, Y., 2022, Description of Leptolaimus boucheri sp. nov. (Nematoda: Leptolaimidae) from the Bohai Sea, China, Journal of Natural History 55 (47 - 48), pp. 2951-2960 : 2953-2954

Leptolaimus boucheri sp. nov.

( Figures 1–3 and Table 1 )

Type material

Three males and four females were collected from the Bohai Sea , China . Holotype male on slide DST151-98. Paratypes on slides DST2-7, DST151-99, DST151-86, DST151-81, DST151- 92 and DST151-87.

Type locality and habitat

All specimens were found in muddy sediments of the 0–2 cm and 2–5 cm layers, intertidal zone of Tianjin Bay along the Bohai Sea, China (39.209°N, 117.955°E) .

Etymology

The species is named in honour of Dr Guy Boucher, in recognition of his contributions to nematode taxonomy.

Measurements

All measurement data are given in Table 1 .

Description

Males. Body slender, 545–602 μm long, tapering towards anterior and posterior ends, greatest body diameter at middle of body. Cuticle distinctly annulated along the body; annuli 2–3 μm wide, without ornamentation. Lateral alae present, 2 μm wide at mid-body, originating in the middle of the pharynx and extending along the body to almost half of tail length. Numerous body pores present in sublateral position at both sides of lateral field. Anteriormost body pore located at lateral field and level of buccal cavity base, about 30 μm from the cephalic apex. Somatic setae not observed. Labial region truncate, slightly offset from body contour. Inner labial sensilla and outer labial sensilla not visible. Cephalic sensilla papilliform. Amphideal fovea circular, 62.5% of corresponding body diameter, situated 9–10 μm from the cephalic apex. Buccal cavity long, cylindrical, 35–38 μm deep, 40–44% of pharyngeal length. Pharynx slender, posterior region swollen and forming oval basal bulb. Cardia cylindrical, with posterior part embedded in intestine. Nerve ring surrounding pharynx at 66 µm from the anterior end. Secretory-excretory system indistinct. Tail conico-cylindrical, 3.8–4.5 cloacal body diameter in length, anterior conical portions gradually transforming to posterior slender cylindrical portions, posteriorly swollen. Caudal glands indistinct. Spinneret present. Caudal setae sparse, and usually six to eight caudal setae distributing subventral and subdorsal sides of tail.

Reproductive system with two opposed testes. Anterior testis outstretched, posterior one reflexed. Spicules slender, slightly arcuate, proximally cephalated and distally pointed. Gubernaculum plate-like, curved to spicules, without apophyses. Accessory apparatus composed of a papilla, four evenly spaced tubular supplements and 15–21 successive alveolar supplements. A papillary supplement just anterior to the cloaca. Tubular precloacal supplements almost straight, with tapered tip, 11 μm long. Winged alveolar supplements with cuticularised wall. The most anterior alveolar supplement located at level of posterior portion of pharynx, 102–112 μm from the anterior end. The posteriormost one situated about 20 μm anterior to the anteriormost tubular supplement, 371–417 μm from the anterior end. Four evenly spaced tubular supplements extending for 82–87 µm from cloaca forward. The posteriormost tubular supplements 23–25 μm in front of cloaca.

Females. Similar to males in most aspects except body slightly thicker (24–27 μm vs 18–19 μm), amphideal fovea slightly smaller (3 µm vs 5 µm wide in males) and having a single ventral pre-anal supplements. Supplement tubular, 6–8 μm long, situated 36– 50 μm anterior to anus. Reproductive system didelphic, with two opposed, reflexed ovaries, located to the left side of intestine. Mature eggs large, oval-shaped. Spermathecae not observed. Vagina straight, 0.25 times vulval body diameter long. Vulva midventral, slightly raised, located at mid-body length, 51–53% of total body length from the anterior end.

Figures

Figure 1. Leptolaimus boucheri sp. nov. (a) Pharyngeal region of female; (b) entire view of holotype; (c) posterior portion of female,showing tail and pre-anal supplement; (d) anterior end of holotype, showing amphid, cuticle pore and lateral ala; (e) posterior portion of male, showing spicule, gubernaculum and precloacal supplements; (f) entire view of female,showing reproductive system; (g) higher magnification of spicule, gubernaculum, papillary and tubular precloacal supplements. Scale bars: 20 µm.

Figure 2. Leptolaimus boucheri sp. nov. (a) Pharyngeal region of holotype, showing amphid (arrow) and posterior bulb; (b) posterior portion of holotype, showing spicule (arrow); (c) posterior portion of holotype, showing gubernaculum, papillary and tubular precloacal supplements; (d) posterior portion of holotype, showing alveolar supplements (arrows). Scale bars: 20 µm.

Figure 3. Leptolaimus boucheri sp. nov. (a) Pharyngeal region of female, showing amphid (arrow) and posterior bulb; (b) posterior portion of female, showing pre-anal supplement (arrow) and tail; (c) cloacal region of male, showing gubernaculum, papillary and tubular supplements; (d) magnification of alveolar supplements (arrow). Scale bars: a, b = 20 µm; c, d = 10 µm.