Leptolaimoides haploopis Jensen, 1978

Holovachov, Oleksandr, 2015, Swedish Plectida (Nematoda). Part 9. The genus Leptolaimoides Vitiello, 1971, Zootaxa 3955 (1), pp. 83-100 : 84-85

Leptolaimoides haploopis Jensen, 1978

( Fig 2 ; Table 1 )

Material examined. Seven males and seven females (slides # 140604 – 140607) deposited in the general invertebrate collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden.

Habitat and locality. Gravel, mud and algae from 30–70 m deep, Skagerrak off the coast of Sweden (N 58° 22' 14'', E 11° 05' 00''), 0 9 August 2011, legit O. Holovachov (seven males and seven females).

Description. Adult. Body tapering anteriorly in pharyngeal region and posteriorly on tail; straight or ventrally curved upon fixation, more strongly curved ventrad in posterior part in males. Maximum body diameter at vulva in female; male body more cylindrical. Cuticle annulated; annuli 1–1.5 µm wide at mid-body, without ornamentation; annulation at level of amphid same as annulation along rest of body. Lateral field present, consists of three alae, middle ala smooth, outer alae areolated, 3–4 µm wide at mid-body; arising at the posterior end of amphid and extending posteriorly to mid-tail length. Prominent body pores in sublateral position at both sides of lateral field, arising from oval lateral epidermal gland cells; usually three-four pairs of body pores present along pharyngeal region; several body pores scattered over rest of body. Anterior-most body pore located posterior to amphid and stoma base, at level of procorpus. Labial region rounded, continuous with body contour, lips fused. Inner and outer labial sensilla indistinct. Cephalic sensilla short, setiform, 1–1.5 µm long. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea elongated, an inverted U-shaped, inner borders sometimes visible; located at level of posterior part of stoma and anterior part of procorpus. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretory-excretory system indistinct. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with weakly developed pyriform basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia cylindrical, its posterior part embedded in intestine. Tail almost similar in shape in both sexes (more curved ventrad in male), elongateconoid in its proximal part (equal to 53–60% of total tail length), subcylindrical in distal. Three caudal glands present, with nuclei incaudal. Spinneret functional.

Male. Reproductive system diorchic; anterior testis outstretched, located on right hand side of intestine; posterior one reflexed. Spicules paired, symmetrical, with arcuate subcylindrical calamus and ovoid manubrium. Gubernaculum plate-like, 4–5 µm long, with 4–6 µm long double caudal apophysis. Accessory apparatus composed of one midventral precloacal papilliform sensillum located on anterior cloacal lip; tubular and alveolar supplements absent. Sublateral precloacal sensilla absent, four caudal sensilla arranged in two subventral pairs. Four small papillae located at the posterior edge of lateral field, one subventral pair and one subdorsal pair.

Female. Reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously. Anterior genital branch 35–67 µm long (equal to 7–14% of total body length), located on right-hand side of intestine (n=7), posterior genital branch 38–72 µm long (equal to 8–14% of total body length), located on left-hand side of intestine (n=7). Oviduct a narrow tube. Two offset, oval, sac-like spermathecae located on each (right and left) side of each (anterior and posterior) gonoduct. Spermathecae and oviducts filled with oval spermatozoa. Uterus a short tube. Vagina straight, 0.3–0.4 times vulval body diameters long; pars proximalis vaginae encircled by single sphincter muscle; pars refringens vaginae absent. Vulva midventral. Epiptygmata and sensory structures around vulva absent. Supplements absent. Rectum 1.0–1.6 anal body diameters long; surrounded by three gland-like cells at intestine-rectum junction.

Diagnosis (supplemented with literature data). Leptolaimoides haploopis is particularly characterised by the 455–766 µm long body; cephalic sensilla 1–1.5 µm long; amphid 12–30 µm long, located 8–14 µm from anterior end; first body pore located 25–32 µm from anterior end; lateral field areolated, arising 22–29 µm from anterior end; female without supplements, vagina without pars refringens, vulva midventral; male without tubular and without alveolar supplements; spicules arcuate and 16–24 µm long.

Remarks. Current specimens agree well with the type specimens in general morphology, shape of anterior end, amphids, lateral alae, spicules and gubernaculum. The only differences are shorter body length (455–609 µm vs. 766 µm in holotype) and amphid (11.5–20 µm vs. 30 µm in holotype).

Figures

FIGURE 2. Leptolaimoides haploopis Jensen, 1978, male (A – C) and female (D – E). A: Pharyngeal region, median section; B: Anterior end, surface view; C: Male posterior region; D: Female reproductive system (anterior part); E: Female tail. Scale bar: A – E = 20 µm.