Propanagrolaimus filiformis (de Man, 1880)

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 : 869-872

Propanagrolaimus filiformis (de Man, 1880)

( Figures 1 , 2 )

Measurements

See Table 1.

Description

Female. Body very slender, almost straight or slightly curved ventrally upon fixation. Cuticle finely striated. Hypodermis with conspicuous glands opening to exterior through fine pores. Lateral field with two lines. Lip region continuous with main body contour. Lips fused, labial sensilla indiscernible in LM. Amphids inconspicuous. Stoma narrow, funnel-shaped 1.1–1.6 lip diameter long or 3.0–5.1 times longer than wide. Cheilostom weakly cuticularized; gymnostom weakly cuticularized, equal to stegostom; dorsal metastegostomal wall bearing a very minute, almost indiscernible tooth. Pharyngeal collar surrounding 30–40% of stomal length. Pharynx comprising of 105–126 µm long, slender corpus; 35–52 µm long, slightly narrow isthmus; elongate basal bulb of 20–26 × 12–19 µm dimension with grinder and single-chambered haustrulum. Nerve ring located at 65–85% surrounding the isthmus, excretory pore at 71–85% of pharyngeal length. Deirids could not be seen. Body at pharyngeal end 2.8–3.5 lip diameters wide. Cardia 5–7 µm long with rectangular flaps. Intestine granular with a narrow lumen. Rectum with expanded lumen, 1.1–1.5 anal body diameter long. Anal opening crescent-shaped. Reproductive system monodelphic, prodelphic. Ovary dorsally reflexed, at right side of intestine with distal end reaching beyond vulva. Oocytes arranged in two rows, at distal tip continuing into a single row. Aggregates of rounded sperms found towards proximal part of oviduct. Up to 15 intra-uterine eggs observed in most females at different stages of embryonation. Vagina thin-walled, anteriorly directed, 1 / 3rd of corresponding body diameter. Vulva a transverse slit, with slightly protruded lips. Post-uterine sac rudimentary, absent in few specimens. Vulva– anus distance 162–242 µm. Tail long, conoid almost straight with narrow obtuse terminus. Phasmids inconspicuous.

Male. Not found.

Habitat and locality

The sample containing Propanagrolaimus filiformis was collected from shore of drain (alluvium soil) at Qasimpur, Aligarh, Uttar Pradesh, India at 27 ◦ 53 ′ N, 78 ◦ 05 ′ E .

Voucher material

Nineteen females on slide Propanagrolaimus filiformis NOQ / 1-7 deposited in the Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India. Two females on slide Propanagrolaimus filiformis No. NOQ / 8,

deposited at the Laboratory of Nematology, Wageningen University and Research Center (WUR), 6700 ES Wageningen, the Netherlands.

Remarks

The present population conforms well to P. filiformis (de Man, 1880) in all morphometric and morphological details but shows some minor differences in having distinctly glandular hypodermis, relatively anterior vulva, smaller intra-uterine eggs, dilated rectal lumen and smaller tail. The outstanding features are the presence of hypodermal glands opening subdorsally and subventrally through pores that might have been overlooked in earlier observations. The ovoviviparous females show embryonating eggs with variable stacking patterns. The absence of males in the population, yet presence of sperms in the female genital tract, is indicative of a hermaphroditic mode of reproduction. Hermaphroditism has also been reported in P. filiformis by Hirschmann (1952).

Figures

Figure 1. Propanagrolaimus filiformis (de Man 1880). (A) Female, entire; (B) anterior end; (C) pharyngeal region; (D) body region showing opening of hypodermal glands; (E) female reproductive system; (F) caudal region.

Figure 2. Propanagrolaimus filiformis (de Man 1880). (A, B) Anterior end; (C) pharyngeal region with pharyngeal corpus and isthmus; (D) body region showing posterior pharynx; (E) body region showing opening of hypodermal glands; (F) body region showing ovarian flexure; (G) vulval region showing reflexed ovary; (H) vulval region with protruded vulval lips; (I–K) intrauterine egg arrangement. (L, M) female anal region; N caudal region showing fine gland openings (scale bar = 10 µm).