Mononchoides composticola Steel, Moens, Scholaert, Boshoff, Houthoofd & Bert 2011

Mononchoides composticola Steel, Moens, Scholaert, Boshoff, Houthoofd & Bert, 2011

(Figs 1–3)

Material examined: Ten females and seven males from vermicompost, in good state of preservation.

Measurements. See Table 1.

Adult: Body slightly arcuate ventrad when heat-killed. Cuticle 1 Μm thick, lacking punctation, with 14–16 prominent longitudinal ridges at midbody, all ridges equidistant and bearing fine transverse striations, 1.3 mm wide at midbody. Lip region continuous with body contour, consisting of six fused lips. Amphids with oval shaped aperture located at the level of the dorsal tooth, about 4–5 µm wide. Buccal cavity about 4.1–4.3 times longer than wide. Cheilostom with 10–12 narrow rib-like plates (cheilorhabdia) that are bifurcate at the apex and extend beyond the labial contour when posterior stomatal elements are retracted; inner wall of cheilostom cuticularized. Second part of stoma consisting of gymnostom and stegostom, both isotopic with subventral walls slightly longer than dorsal ones. Gymnostom, about 10 µm wide, forming a cuticular isomorphic cylinder with its anterior edge not serrated; its dorsal side cuticularized, thickened at the middle, remaining more uniformly in its shape. Promesostegostom wide in dorsal sector and relatively thin in subventral sectors. Metastegostom bearing dorsally a prominent claw-like tooth, 7–9 µm long and 3–5 µm wide, pointed toward anterior part, having the duct of the dorsal gland and subventrally, a smaller sickle-shaped right tooth. Posterior part of stegostom (telostegostom) forming a cylindrical tube, 5–6 µm wide and 13–15 µm long; minute denticle observed in the subventral wall of the stegostom. Neck region comprising 15–18% of total body length. Pharynx diplogasteroid; pharyngeal procorpus cylindrical, 2.9–3.4 times the metacorpus length; metacorpus swollen; isthmus robust, longer in males; basal bulb lacking valvular apparatus. Cardia conoid, surrounded by intestinal tissue. Nerve ring at 66–71% of neck length, at isthmus level. Excretory pore situated at level of the middle part of isthmus, at 113–141 Μm from the anterior end, at 72% of neck length. Hemizonid anterior to excretory pore. Deirid not observed.

* Stoma + pharynx.

Female: Reproductive system didelphic-amphidelphic, with both branches equally developed and reflexed terminus often reaching the vulva level; ovaries totally reflexed (antidromous flexion) with oocytes arranged in one or two rows in the germinative zone; germinative and growth zones slightly broad, distinctly separated from each other. Oviducts narrow and short, with the spermatheca not set off from the uterus. Uteri 2.0–2.5 times as long as the corresponding body diameter. A pair of dumb-bell-shaped pouches present at proximal part of uterus (ovijector), 22–28 Μm long, connecting both uteri. Vagina with narrow lumen and extending inwards, less than half of the corresponding body diameter. Vulva anterior to midbody. Vulva lips weakly cuticularised, not protruding, pore-like, pre-equatorial. Rectum 1.0–1.3 times anal body diameter long. Phasmids prominent, situated at 5–7% of tail length. Tail first conical then filiform, 1.6–2.4 times the vulva-anus distance long.

Male: General morphology similar to female but with cephalic setae (2.7–3.6 µm). Spicules stout, paired, separate in ventral view, smoothly ventrally arcuate in lateral view; rounded manubrium at anterior end; lamina/ calamus complex expanded just posterior to manubrium, then slightly tapering to smoothly pointed distal end. In lateral view, the gubernaculum is expanded proximally and pointed distally. Nine pairs of genital papillae (P1–P9) and a pair of phasmids (Ph) present, arranged as P1, P2, P3, P4, (P6, P7, P8) and P9 [according to the nomenclature of Sudhaus & Fürst von Lieven (2003)]. All papillae seta-like, and P6, P7 and P8 rather smaller and closer to each other. Phasmid (Ph) and P4 are clearly separated. Phasmids located at 1.0–1.2 anal body widths behind the cloacal aperture. Tail filiform.

Locality and habitat. The species was collected in Kerman (province of Kerman, Iran; N: 30°15'27.10", E: 57°06'13.59”), associated with vermicompost.

Remarks. The Iranian material agrees well with the original description of M. composticola provided by Steel et al. (2011) from Belgium. The specimens examined do not have significant differences in morphology and morphometrics. On the other hand, Mahamood et al. (2007) described a population of an unidentified species of Mononchoides from India which is similar to our population, only differentiated in the length of gubernaculum, theirs being slightly shorter (10–20 vs 14–22 µm); this material is probably conspecific with ours.

This species is reported for the first time from Iran.