Elzalia longicaudata, Lu & Sui & Huang, 2022

Lu, Yang, Sui, Xinxin & Huang, Yong, 2022, Three new species of free-living marine nematodes from the central basin of the South China Sea, Journal of Natural History 56 (17 - 20), pp. 1091-1107 : 1093-1095

Elzalia longicaudata sp. nov.

( Figures 1–2 and Table 1 )

Type material

Two males and three females were collected from Stations S5 (20.650°N, 118.308°E, water depth 2368 m) and S1 (21.549°N, 118.898°E, water depth 2694 m). Holotype: male 1 on slide NHS5-34-3, paratypes: male 2 on slide NHS5-39-5, female 1 on slide NHS5-41-4, female 2 on slide NHS5-34-1 and female 3 on slide NHS1-321-7.

Type locality and habitat

The holotype was found in muddy sediment at Station S 5 in the South China Sea (20.650° N, 118.308°E, water depth 2368 m) .

Etymology

The species name is derived from the Latin adjective longus (long) and caudatus (tail), referring to its long tail.

Measurements

All measurement data are given in Table 1 .

Description

Holotype male. Body slender. Round labial region set off from adjacent body by constriction. Cuticle with fine striations. Somatic setae not observed. Inner labial sensilla papilliform. Six outer labial setae and four cephalic setae arranged in one circle, and almost equal in length, about 3 μm long. Four cervical setae 7–8 μm long, located posterior to the base of the buccal cavity. Amphidial fovea oval, relatively large, 9 μm in diameter (53% of corresponding body diameter), located at the level of base of buccal cavity, 12 μm from its front edge to the anterior end. Buccal cavity cylindrical, cuticularised, 15 µm deep and 5 µm wide. Pharynx cylindrical, slightly swollen at base, not forming posterior terminal bulb. Cardia nearly spherical, projecting into the intestine. Nerve ring situated just anterior to the middle of pharynx. Secretory–excretory system not observed. Tail conical with a long filiform posterior portion, 7.5 times abd, with two terminal setae, 6–8 µm long. Caudal setae not seen. Three contiguous caudal glands with common opening.

Reproductive system with single anterior outstretched testis. Spicules paired, elongate, slender and equal in length, 71 µm long, i.e. 3.7 abd, or 9% of body length, curved as the body bends, proximal end truncated, distal end tapered. Gubernaculum rather simple, with only one section of dorsal apophysis, about 10 µm long.

Females. Similar to males in most morphological characteristics except amphidial fovea smaller and circular (6–7 µm in diameter). Reproductive system monodelphic with a single anterior outstretched ovary, located to the left of the intestine. Vagina straight, 0.4 times vulval body diameter long. Vaginal glands present. Vulva situated at about mid-body.

Figures

Figure 1. Elzalia longicaudata sp. nov. (a) Lateral view of male pharyngeal region; (b) anterior end of male, showing buccal cavity, cephalic setae and cervical setae;(c) posterior region of male; (d) anterior end of female, showing buccal cavity and amphid; (e) cloacal region of male, showing spicule and gubernaculum; (f) entire female; (g) vulval region, showing vulva and egg. Scale bars: a, c, d = 20 µm; b, e, g = 10 µm; f = 50 µm.

Figure 2. Elzalia longicaudata sp. nov. (a) Lateral view of male pharyngeal region, showing amphid; (b) anterior end of male, showing buccal cavity, cephalic setae and cervical setae; (c) male tail; (d) cloacal region of male, showing spicules; (e) cloacal region of male, showing gubernaculum. Scale bars: a, c, d = 20 µm; b, e = 10 µm.