Stegelleta ophioglossa Andrássy, 1967b

Abolafia, Joaquín & Peña-Santiago, Reyes, 2015, Some rare species of cephalobs (Nematoda: Rhabditida: Cephalobidae) from Southern Iberian Peninsula, Journal of Natural History 50, pp. 557-581 : 565-569

Stegelleta ophioglossa Andrássy, 1967b

( Figures 2F – K , 4A – E )

Material examined

Two females from one locality, in good state of preservation.

Morphometrics

See Table 1.

Description

Female. Stout to moderately slender nematodes, 0.33 – 0.40 mm long. Habitus weakly curved ventrad after fixation. Cuticle deeply annulated and tessellated, with 16 longitudinal rows of blocks at midbody. Lateral field with two wings separated by a narrow groove, appearing as four longitudinal incisures under LM, occupying 27% of midbody diameter and extending posteriorly almost to tail tip. Lip region continuous with the adjacent body; three pairs of asymmetrical lips, one dorsal and two ventrolateral, with more or less straight and smooth margins and bearing six labial and four cephalic sensillae; primary axils deep and U-shaped, and secondary axils demarcated by a shallow incisure, both lacking guarding processes; oral opening surrounded by three labial probolae, connected at bases by tangential ridges; each labial probola bifurcated, snake-tongue-shaped, with prongs long and convergent, curved, lacking lateral tines and secondary bifurcations. Amphids clearly visible, small and with oval shape. Stoma cephaloboid: cheilostom with well-developed rounded rhabdia, gymnostom very short, and stegostom with minute discernible rhabdia. Pharynx typical of the group: corpus 3.0 – 4.6 times isthmus length, slightly fusiform; corpus – isthmus junction slightly swollen at corpus and narrower at isthmus; isthmus slender, demarcated by a break in muscular tissue; basal bulb ovoid, with valvular apparatus. Nerve ring at 68 – 82% of neck length, at level of isthmus. Excretory pore at 75% of neck length, at level of isthmus, 41 annuli from anterior end. Deirids at 92% of neck length, at level of bulb, 47 annuli from anterior end. Cardia conoid, surrounded by intestinal tissue. Intestine without distinct specializations. Reproductive system monodelphic-prodelphic, in a dextral position to intestine: ovary short, with flexures at the postvulval part; oviduct short; spermatheca reduced, half as long as the corresponding body diameter; uterus tubular, 2.3 – 3.2 times as long as the corresponding body diameter; postvulval sac short, 0.5 – 0.6 times as long as the body diameter; vagina short, extending inwards 27 – 36% of body width; vulval lips not protruding. Rectum as long as the body width at anus level, having three large glandlike cells around the intestine – rectum junction. Tail conical with rounded terminus. Phasmids located at 34 – 43% of tail length.

Male. Unknown.

Distribution

This species was collected from two localities: (i) Murcia province, in a greenhouse with biofumigate soil; and (ii) Almería province , Salinas de Cabo de Gata, volcanic sandy soil, in association with Sarcocornia fruticosa (L.) Scott .

Remarks

The description above and morphometrics agree with those of other known populations from Mongolia ( Andrássy 1967b), Uzbekistan ( Mavljanov 1978; as S. cylindrica , a junior synonym according to De Ley et al. 1990), Senegal ( De Ley et al. 1990; Boström and Holovachov 2014) and Iran ( Shokoohi et al. 2008) (see Table 3). Type material from Mongolia, however, differ from other populations in having appreciably larger body size (470 – 490 vs 315 – 403 µm long), longer labial probolae (8 vs 4 – 7 µm long), and lower number of longitudinal rows of cuticle blocks (14 vs 16). The specimens described as S. ophioglossa by Orselli and Vinciguerra (2002) from Italy corresponds with S. incisa according to Boström and Holovachov (2014).

The material described here from Murcia was reported previously by Abolafia et al. (2011), but is now being re-examined to provide new data. The material from Almería was preserved for molecular analysis.

Figures

Figure 2. Heterocephalobellus magnificus (Andrássy, 1987) De Ley et al. 1993a (LM, juvenile): (A) neck region (arrow points at excretory pore); (B) stoma; (C) lip region; (D) genital primordium; (E) posterior end. Stegelleta ophioglossa Andrássy, 1967b (LM, female): (F) neck region (arrow points at excretory pore); (G) lip region (arrow points at amphid); (H) vagina region; (I, J) posterior end at rectum and lateral field levels, respectively (arrow points at phasmid); (K) cuticle.

Figure 4. Stegelleta ophioglossa Andrássy, 1967b (female): (A) neck region; (B) anterior region; (C) lateral field; (D) reproductive system; (E) posterior end. Nothacrobeles nanocorpus De Ley, De Ley, Baldwin, Mundo-Ocampo and Nadler, 1999: (F) lip region; (G) neck region; (H) female reproductive system; (I) lateral field; (J) female posterior end; (K) male posterior end.