Propanagrolaimus hygrophilus ( Bassen, 1940 )

Khan, R., Hussain, A. & Tahseen, Q., 2012, Descriptions of one new and two known species of Panagrolaimoidea (Nematoda) from India, Journal of Natural History 46 (13 - 14), pp. 867-884 : 872-876

Propanagrolaimus hygrophilus ( Bassen, 1940)

( Figures 3 , 4 )

Measurements

See Table 1.

Description

Female. Body very slender, almost straight or slightly curved ventrally upon fixation, tapering at both extremities. Cuticle finely annulated, annuli 0.5 µm wide. Lateral field a narrow band, with three crenate lines. Lip region continuous with body contour. Lips fused, labial sensilla inconspicuous. Amphids small, oval slits, located posterior to cheilostom. Stoma narrow, tubular about 1–1.5 lip diameter long. Cheilostom not cuticularized, gymnostom about 60% of stomal length, thick, more cuticularized than remaining stomal components. Telostegostom continuous with pharyngeal lumen. Pharynx comprising of slender, 92–115 µm long corpus; 39–48 µm narrow isthmus and a rounded, basal bulb of 21–25 × 14–19 µm dimension with grinder and singlechambered haustrulum. Nerve ring located at about 63–71% of pharyngeal length, surrounding the isthmus. Excretory pore without a cuticularized duct, at 65–81% of pharyngeal length at isthmus level. Body at proximal end of pharynx about 2.8–3.8 lip diameter wide. Cardia small, flat, 4–7 µm long with narrow lumen. Intestinal cells appearing vacuolated surrounding a narrow lumen. A cluster of parallel canal-like structures observed in pseudocoelom in posterior pharyngeal region and around postuterine sac. Rectum with markedly cuticularized lumen, 1.4–1.7 anal body diameter long. Rectal glands inconspicuous. Anus a crescent-shaped slit. Reproductive system monodelphic, prodelphic. Ovary laterally reflexed, on right of intestine; reflexed portion straight, extending beyond vulval level. Oocytes arranged in a single row. Oviduct leading to a small spermatheca containing few sperms and a reduced crustaformeria. Intra-uterine eggs of 51–62 × 15–18 µm dimension, observed in few females. Vagina at right angle to longitudinal body axis, thin-walled, 1 / 3rd–1 / 4th of corresponding body diameter long. Vulva a transverse slit, with slightly protruded lips. Post-uterine sac 20–38 µm or about one vulval body diameter long. Vulva–anus distance 202–351 µm. Phasmids located at middle of tail. Tail elongate, straight to a narrow, subacute terminus.

Male. Not found.

Habitat and locality

Sample containing Propanagrolaimus hygrophilus was collected from the bank of pond (alluvium soil mixed with sand) near Gonda, Aligarh, Uttar Pradesh, India at 27 ◦ 49 ′ 60 N, 77 ◦ 52 ′ 60 E geographical coordinates .

Voucher material

Eighteen females on slides Propanagrolaimus hygrophilus NOG / 1-10 deposited in the Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India. Two females on slide Propanagrolaimus hygrophilus NOG / 11 deposited at the Laboratory of Nematology, Wageningen University and Research Center (WUR), 6700 ES Wageningen, the Netherlands.

Remarks

The present population conforms to the earlier reported populations in morphological characteristics. A cluster of canal-like structures as visible in the pseudocoelom ( Figures 3D , 4F, G, I ) of present specimens has not been reported earlier except that the original description (apud Bassen 1940) indicated presence of convoluted excretory canals. However, these structures could not be designated as excretory canals in the present population due to their variable positions and apparent absence of a connection.

Figures

Figure 3. Propanagrolaimus hygrophilus (Bassen, 1940). (A) Female, entire; (B) anterior end; (C) pharyngeal region; (D) body region posterior to pharynx with canal-like structures; (E) female reproductive system; (F) body region showing uterus and post-uterine sac (G) caudal region.

Figure 4. Propanagrolaimus hygrophilus (Bassen, 1940). (A, B) Anterior end; (C) body region showing pharyngeal corpus; (D, E) body region showing posterior pharynx; (F, G, I) body region showing canal-like structures; (H) part of female reproductive system; (J) lateral field area; (K) anal region (scale bar = 10 µm).