Diplopeltoides grandis, Holovachov & Boström, 2017

Holovachov, Oleksandr & Boström, Sven, 2017, Three new and five known species of Diplopeltoides Gerlach, 1962 (Nematoda, Diplopeltoididae) from Sweden, and a revision of the genus, European Journal of Taxonomy 369, pp. 1-35 : 27-29

Diplopeltoides grandis sp. nov.

urn:lsid:zoobank.org:act:1954B3FA-0622-45CD-AF8C-EA3954F9EE3C

Figs 10 , 11 B–C; Table 6

Diagnosis

Diplopeltoides grandis sp. nov. is characterised by a body of 2.06 mm long; cuticle with longitudinal striation; cuticularised plate underlying cephalic cuticle around amphid present; cephalic sensilla setiform, 18.5 µm long; amphidial fovea an inverted U-shape, 30 µm long and 14 µm wide; wide space between amphidial branches punctate; excretory pore indistinct; tail conoid.

Etymology

The specific epithet refers to the large body size in this species.

Type material

Holotype

SWEDEN: ♀, Skagerrak , 58°20.32′–20.38′ N, 11°12.73′–12.68′ E, coarse shell sand 14–17 m deep, 19 Aug. 2014, O. Holovachov and U. Jondelius leg. ( SMNH Type-8844 ).

Description

Adult female

Body cylindrical, posteriorly tapering in tail region, curved upon fixation. Cuticle coarsely annulated along entire body, except for smooth anterior end and terminal part of the tail; annules 3 µm wide at mid-body region; longitudinal striation is distinct under light microscope, covers annules over entire body length. Somatic setae indistinct. Labial region truncate conoid, lips fused. Cuticularised plate underlying cephalic cuticle around amphid strongly developed, extending from the level of cephalic setae bases to the posteriormost edge of amphid, 38 µm long and 23 µm wide at base; cuticular plates connected with each other on ventral and on dorsal sides. Inner labial sensilla not seen, outer labial sensilla small papilliform, located on the anterior surface of lips. Cephalic sensilla setiform, equal to 1.4 labial region diameters in length, their bases located 4 µm from anterior end. Amphidial fovea an inverted U-shape with dorsal branch longer than ventral branch. Wide space between amphidial branches (amphidial shield) heavily cuticularised and punctate. Stoma very small, its cuticularised lining uniform with lining of the pharynx. Pharynx distinctly subdivided into anterior corpus and posterior postcorpus; corpus fusiform, muscular; postcorpus consists of anterior narrow non-muscular isthmus and pear-shaped glandular basal swelling. Pharyngeal gland nuclei and orifices indistinct. Nerve ring surrounding isthmus. Secretory-excretory system not observed. Tail conoid. Caudal glands opening via three separate openings, spinneret absent. Reproductive system didelphic, amphidelphic, reflexed; ovary branches symmetrical. Anterior ovary situated to right of intestine; posterior ovary situated to left of intestine. Vulva a transverse slit, located immediately posterior to mid-body. Vagina straight, 0.2 of the vulval body diameter, with thick walls; pars refringens vaginae absent. Intrauterine egg or sperm not observed. Rectum short, 0.6 of the corresponding body diameter long.

Male

Not found.

Remarks

Diplopeltoides grandis sp. nov. is most similar to D. axayacatli in having a relatively large body size, a distinctly striated cuticle and a developed cuticularised plate. The new species differs from D. axayacatli in the shape of the amphid (loop-shaped, with parallel branches vs hook-shaped, with one of the branches bent inward, in D. axayacatli ) and its size (30 × 14 µm vs 11–15 × 8–9 µm in D. axayacatli ).

Figures

Fig. 10. Diplopeltoides grandis sp. nov. A. Female anterior end, surface view. B. Female tail. C. Female pharyngeal region, optical median section. D. Vulval region. Scale bar = 20 µm.

Fig. 11. Light microscopy images of anterior ends. A. Diplopeltoides bulbosus (Vitiello, 1972) comb. nov., female, amphid. — B–C. Diplopeltoides grandis sp. nov., holotype, female. B. Amphid. C. Cuticularised plate. Scale bars: A–C = 20 µm.