Fig 9. A–C; Table 6
Diplopeltoides linkei is characterised by a body of 0.48–0.63 mm long; cuticle with longitudinal striation; cuticularised plate underlying cephalic cuticle around amphid present; cephalic sensilla setiform, 2–3 µm long; amphidial fovea an inverted U-shape, 14–19 µm long and 7–8 µm wide; narrow space between amphidial branches not ornamented; secretory-excretory pore located opposite to isthmus; tail conoid; testes opposed; spicules 29–36 µm long, strongly curved, with round manubrium and subcylindrical shaft; gubernaculum plate-like, without apophyses.
SWEDEN: 1 ♂, Skagerrak, 58°28′22.1″–19.2″ N, 10°29′35.6″–43.6″ E, soft bottom 248–316 m deep, 11 Oct. 2012, “Inventering Bratten” leg. (SMNH-159564); 1 ♂, Gullmarn Fjord near Lysekil, 58°15.73′ N, 11°26.10′ E, mud from 53 m deep, 14 Aug. 2014, O. Holovachov and U. Jondelius leg. (SMNH-159565).
Adult male
Body cylindrical, posteriorly tapering in tail region, weakly curved upon fixation. Cuticle coarsely annulated along entire body, except for smooth anterior end (annulation starts at level of posterior ¼ of amphid) and terminal part of tail; annules 3–4 µm wide at mid-body region; longitudinal striation is distinct under the light microscope, covers annules over entire body length. Somatic setae not observed. Labial region bluntly rounded. Cuticularised plate underlying cephalic cuticle around amphid strongly developed, extending from level of anteriormost edge of amphid to level of posteriormost edge, 18.5–19 µm long and 13–14.5 µm wide at base; cuticular plates connected with each other on ventral and on dorsal sides. Inner and outer labial sensilla not seen. Cephalic sensilla setiform, equal to 0.3 labial region diameters in length, their bases are located 3.5–4 µm from anterior end. Amphidial fovea an inverted U-shape with ventral branch longer than dorsal branch. Narrow space between amphidial branches (amphidial shield) not cuticularised and not ornamented. Stoma very small, its cuticularised lining is uniform with lining of the pharynx. Pharynx distinctly subdivided into anterior corpus and posterior postcorpus; corpus cylindrical or slightly fusiform, muscular; postcorpus consists of anterior narrow non-muscular isthmus and pear-shaped glandular basal swelling. Pharyngeal gland nuclei large, orifices of pharyngeal glands indistinct. Nerve ring surrounding isthmus. Secretory-excretory system present; secretory-excretory pore located along ventral body line opposite to isthmus; secretory-excretory duct very short; renette cell not observed. Tail conoid. Caudal glands opening via three separate openings, spinneret absent. Reproductive system diorchic, testes opposed: anterior testis outstretched and posterior testis reflexed. Spicules paired and symmetrical, strongly curved, with round manubrium and subcylindrical shaft. Gubernaculum plate-like, without apophyses. Caudal setae: two subventral pairs and single subdorsal.
Female
Not found.
The recently collected population of D. linkei is similar to the type specimens from the Norwegian Sea in general morphology, structure of cuticle and anterior end, except for the somewhat longer body ( 0.62–0.63 mm vs 0.48–0.50 mm in type specimens) and longer spicules ( 32–36 µm vs 29 µm).