Stegelleta ophioglossa Andrássy, 1967

Boström, Sven & Holovachov, Oleksandr, 2014, Descriptions of species of Stegelleta Thorne, 1938 (Nematoda, Rhabditida, Cephalobidae) from California, New Zealand and Senegal, and a revision of the genus, European Journal of Taxonomy 87, pp. 1-19 : 12-16

Stegelleta ophioglossa Andrássy, 1967

Fig. 4A–D , Table 3

Stegelleta ophioglossa Andrássy, 1967: 208–210 , fig. 3.

Diagnosis

Stegelleta ophioglossa is characterised by a 315–490 µm long body in females; cuticle divided by regular longitudinal striations into 12–16 rows of blocks at midbody (excluding lateral field); lateral field with four incisures extending almost to tail terminus in females; three pairs of asymmetrical lips, pairs of lips separated by U-shaped primary axils without guarding processes, secondary axils demarcated by a shallow incisure, each lip asymmetrically rectangular with a smooth margin and without tines; three labial probolae, bifurcated at half of their length, prongs bent toward one another apically, “snaketongue”-shaped; pharyngeal corpus 3–5 times isthmus length; nerve ring, excretory pore and deirids at level of isthmus; vulva without flap; spermatheca 7–13 µm long; postuterine sac 7–17 µm long.

Material examined

SENEGAL: 6 ♀♀, SMNH 135943–135944, Kaolack region, Thyssé-Kaymor, legit C. Villenave.

Description

Adult

Body slightly arcuate ventrad when killed by heat. Cuticle annulated, annuli 1.6–2.2 µm wide at midbody and 1.7–2.0 µm wide in pharyngeal region. Cuticle tessellated: longitudinal striae giving it a tiled appearance, 16 rows of blocks at midbody (excluding lateral field). Lateral field consisting of two wings separated by a narrow groove, appearing as four incisures under LM, occupying about 20% of body diameter, extending almost to tail terminus in females. Lip region slightly offset, carrying 6 + 4 papillae and two round amphids. Three pairs of asymmetrical lips, one dorsal and two ventrolateral. Pairs of lips separated by U-shaped primary axils without guarding processes. Each pair with a shallow incisure demarcating a secondary axil. Each lip asymmetrically rectangular with a smooth margin. Three labial probolae, 6–7 µm high, bifurcated at half of their length, prongs bent toward one another apically (“snake-tongue”-shaped). Stoma somewhat longer than lip region diameter. Stomatal parts not clearly discernible. Cheilorhabdia bacilliform in lateromedian view; metastegostom with a dorsal denticle. Pharynx cephaloboid. Pharyngeal corpus cylindrical; isthmus narrow, not clearly demarcated from corpus; bulb oval, with valves. Nerve ring, excretory pore and deirids at level of isthmus.

Female

Reproductive system monodelphic, prodelphic, in dextral position in relation to intestine. Ovary reflexed posteriorly at oviduct, ovary straight posterior to vulva. Spermatheca small, not developed. Postvulval uterine sac short, about one-half of vulval body diameter long. Vagina about one-third of vulval body diameter. Vulval lips not protruding. Tail conoid with 12–20 ventral annuli, terminus truncate. Phasmids located at about one-fourth to one-third of tail length.

Male

Not found.

Remarks

The specimens described here agree in many respects with the population of Stegelleta ophioglossa from Senegal described by De Ley et al. (1990) and several other populations of S. ophioglossa ( Andrássy 1967; Mavljanov 1978; Shokoohi et al. 2008; Abolafia et al. 2011).

Figures

Fig. 4. A–D. Stegelleta ophioglossa Andrássy, 1967. A. Pharyngeal region. B. Anterior end, surface view. C. Female gonad. D. Female tail. E–G. Stegelleta tuarua Yeates, 1967. E. Pharyngeal region. F. Anterior end, surface view. G. Male tail. Scale bar = 20 µm.