Belbolla forkyspicula, Xiao & Guo, 2023

Xiao, Yueping & Guo, Yuqing, 2023, Three new free-living marine nematode species of Subsphaerolaimus Lorenzen, 1978, Halichoanolaimus de Man, 1886 and Belbolla Andrássy, 1973 from mangrove wetlands in Taiwan, Zootaxa 5361 (3), pp. 301-322 : 314-319

Morphological description of Belbolla forkyspicula sp. nov.

urn:lsid:zoobank.org:act:FEF8DFCF-FB96-485C-8C06-A0F7F920E93A

( Figures 6–7 , Table 5 )

Type material. Three males and four females were collected from station GNTH 1 in February 2021. Holotype: ♁1 on slide number GNT20210221 H15. Paratypes: ♁2–3 on slide number GNT20210221 H131, ♀ 1 on slide number GNT20210221 H139, ♀ 2 on slide number GNT20210221 H131, ♀ 3 on slide number GNT20210221 H136 and ♀ 4 on slide number GNT20210221 H140.

Type locality and habitat. All specimens were collected from a mangrove ( Avicennia marina ) forest in Guningtou, Jinmen County. Station JMGNT: 118°18'15.84″E, 24°29'9.24″N.

Etymology. Species epithet refers to the shape of the spicules: like a fork.

Description

Males. Body is medium in length, tapering slightly towards the extremities, anterior body region outstretched anteriorly and strongly tapered anteriorly from the mid-pharynx to head region. Cuticle smooth, without longitudinal ridges and transversely striated. Head diameter 9–10 μm and distinctly narrowing. Inner labial sensilla papilliform, six small papillae and ten cephalic setae (6–7 µm long) arranged in one circle. Dozens of cervical setae, with the anterior cervical setae (12–15 µm long) in one circle, and the others arranged irregularly. Amphidial fovea not observed. Buccal cavity waist drum-shaped, 11 μm deep and 5–6 μm wide, separated into two buccal chambers by a cuticular ring, which is smooth without denticles. Buccal cavity with one large right dorsolateral tooth and two less prominent teeth, which are dorsal and left ventrolateral in position. Nerve ring at 57–60% of the pharynx length. Pharynx is composed of two different parts. Anterior cylindrical, muscular; the posterior part consisting of seven pharynx bulbs, each of which has a cuticle cavity. Renette cell and excretory pore not observed.Cardia small, surrounded by intestinal tissue. Tail short, with a slightly swollen tip, with six terminal setae, 7–8 μm long. Caudal glands present.

Two testes, opposite and outstretched. Anterior testis to the left and posterior testis to the right of the intestine. Spicules 31–38 µm in length, paired, equal and arcuated. Proximal end fork-like, distally tapered. Gubernaculum small, slightly protruding, 13–14 μm long. Two winged precloacal supplements strongly developed, anterior precloacal supplement 14–15 μm long, posterior precloacal supplement 16–17 μm long. Posterior precloacal supplement 130–158 μm from the cloacal opening, and the distance between the two supplements is 59–78 μm. One pair of setae located just in front of the cloaca, approximately 5 µm long.

Females. Similar to male in general characteristics, but with a shorter tail (109–121 μm vs. 98–104.1 μm; c: 12.5–13.9 vs. 15.0–15.2) and without long cervical setae or terminal setae. Reproductive system amphidelphic, ovaries outstretched.Anterior gonad to the left and posterior gonad to the right of the intestine. Vulva at 55.6–57.8% of the body length. Short vagina with thick walls perpendicular to the longitudinal body axis.

Figures

FIGURE 6. Belbolla forkyspicula sp. nov. A: Lateral view of the male anterior part. B: Lateral view of the female anterior part. C: Lateral view of the male head part. D: Lateral view of the female head part. E: Spicule of the male. F: Lateral view of the male posterior part. G: Lateral view of the female posterior part. H: Lateral view of the female reproductive system. Scale bars: A, B, F, G = 25 μm; C, D, E = 10 μm; H = 50 μm.

FIGURE 7. Belbolla forkyspicula sp. nov A: Lateral view of the male anterior part; B: Lateral view of the female anterior part; C: Lateral view of the male head end; D: Lateral view of the female head end; E: Lateral view of the male posterior part; F: Lateral view of the female posterior part; G: Spicule of the male; H: Supplement of the male; I: Lateral view of the female reproductive system. Scale bars: A, B, E, F, I = 25 μm; C, D, G, H, J = 5 μm.