Doryllium minor Jairajpuri, 1963

Ahmad, Wasim, Ahad, Sumaya, Islam, Md. Niraul & Sturhan, Dieter, 2018, Taxonomy of the genus Doryllium Cobb, 1920 (Nematoda: Dorylaimida) with description of two new and a known species, Zootaxa 4441 (2), pp. 261-278 : 262-266

Doryllium minor Jairajpuri, 1963

( Figs. 1–3 )

Material examined. Eighty-two females from seven different localities, most of them in good state of preservation.

Description. For measurements, see Table 1.

Female: Slender nematodes of small size; body cylindrical, slightly curved ventrad upon fixation, tapering slightly towards the anterior extremity, posteriorly ending in a rounded tail. Cuticle with two distinct layers, 2.0 µm thick at midbody and 3–4 µm on tail. Outer cuticle with fine transverse striation; inner layer with distinct transverse striations. Lateral chords occupying about one-fourth to one-third of the midbody diameter. Lip region slightly offset by a weak constriction, 2.0–2.5 times as wide as high and about one-third of body diameter at neck base; lips amalgamated, with rounded contour, inner portion transformed into a perioral disc. Amphids cup-shaped, aperture occupying about one-half of the lip region diameter. Stoma a truncate cone. Odontostyle 0.8–1.1 times the lip region diameter long, aperture about one-fourth of its length. Odontophore with distinct basal knobs, 1.4–2.0 times the odontostyle length. Guiding ring simple, refractive, at 0.8–1.0 times lip region diameter from anterior end. Pharynx consists of a slender and weakly muscular anterior part, separated from basal bulb by a constriction. Pharyngeal bulb cylindroid, occupying about 22–27%of total neck length. Pharyngeal glands often visible. Cardia short, rounded to conoid, about one-fifth to one-fourth of midbody diameter long. Nerve ring located at 42–49% of neck length from anterior end. Genital system monodelphic-opisthodelphic. Ovary reflexed, measuring 39–127 µm long; oocytes arranged in single row except near tip. Oviduct joining the ovary subterminally, separated from the uterus by a narrowing, but with no apparent sphincter seen. Anterior genital branch absent or a rudimentary sac, less than one-third of corresponding body diameter. Vagina cylindrical; pars proximalis vaginae 4–8 µm long, wall encircled by muscles; pars distalis vaginae short, 1.5–2.0 µm long with slightly curved walls; pars refringens absent. Vulva apparently a transverse slit. Prerectum 3.3–4.9 anal body diameters long. Intestine-prerectum junction guarded by three cells. Rectum 0.8–1.0 anal body diameter long. Tail cylindroid, hemispheroid to slightly clavate terminus, 1.3–2.0 anal body diameters long, cuticle at tail terminus thick, hyaline portion of the tail variable; caudal pores two on each side.

Male: Not found

Habitats and localities. Soil samples collected from around rhizosphere of forest trees from:

1 Dachigam National Park , Srinagar , Jammu & Kashmir, India; 34o8’36”N 75o2’16”E

2 Baramullah , Kashmir valley , Jammu & Kashmir, India; 34o11’52.8”N 74o21’50.4”E

3 Kangna valley , Ganderbal district, Jamuu & Kashmir state, India ; 34o9’36”N 75o33’0”E iv). Kigwema , Kohima district, Nagaland, India; 25o60’62”N, 94o12’70” E

4 Gudalur , Theni district, Tamil Nadu, India; 11o50’30”N, 76o49’17”E

5 Ooty , Nilgiris district, Tamil Nadu, India; 11°24'0" N, 76°42'0"E

6 vii). Freiburg , Germany; 47°59'56”N, 7°50'31"E

TABLE]. Measurements of Doryllium minor Jairajpuri, 1963 . (All measurements in µm)

……continued on the next page

TABLE]. (Continued)

Remarks. Jairajpuri (1963) described Doryllium minor from Srinagar, Kashmir, India. Goseco et al. (1975) redescribed this species based on a study of the holotype as well as additional material from Indiana. Goseco et al. (1981) further redescribed this species from Panama while Nasira et al. (2005) redescribed it from Pakistan. The present specimens, collected from three entirely different geographical areas in India, as well as a population from Germany provide a much wider range of morphometric data on this widely distributed species. Interestingly, the morphometric data of all seven of these populations are quite similar without any significant differences; however, some morphological differences were recorded. The three populations from Kashmir valley, the region from where the type population was collected fits well with the original morphometric data provided by Jairajpuri (1963). However, the amphid is rather cup-shaped in the Dachigam National Park and Kangana valley populations, whereas it is stirrup-shaped in the Baramullah population. The outer cuticle is smooth in all three Kashmir populations as well as in the Nagaland population. Jairajpuri (1963) and Goseco et al. (1975) described outer cuticle as smooth. The Nagaland population also has a cup-shaped amphid. The two populations from Tamil Nadu, as well as the German population, have a distinctly striated outer cuticle and cup-shaped amphid. The tail in the Gudalur, Tamil Nadu population is similar to that of the type population, whereas it is rather more clavate in the Ooty population as well as in the German population. None of these morphological differences show a definite combination of characters, hence it is concluded that these differences are simple geographical variations and one has to be very cautious when using these characters individually when differentiating species.

Two Doryllium species, D. cornelli (van der Linde, 1938) Jairajpuri & Siddiqi, 1963 and D. coronatum Brzeski, 1962 are very close to D. minor , however, D. cornelli is characterized by its distinctly sclerotized stoma lining and odontophore almost equal in length to odontostyle. D. coronatum is distinctive in having domed, projecting liplets around oral opening and odontophore about three times as long as odontostyle.

Figures

FIGURE 1. Dorylllium minor Jairajpuri, 1963. A. Entire female; B. Anterior region; C. Anterior end showing amphid; D. Pharyngeal region; E. & F. Pharyngeal bulb; G. Female genital system; H&I. Female posterior region..

FIGURE 2. Doryllium minor Jairajpuri, 1963. A–H. Anterior region (A. Baramullah, B. Dachigam National Park, C– D.Kangan Valley, E. Nagaland, F. Ooty, G. Gudalur, H. Germany). I–P. Pharyngeal Bulb (I–J.Baramullah, K. Dachigam National park, L–M. Kangan Valley, N–O. Ooty, P. Gudalur). A–D & I–M. Kashmir population, E. Nagaland population, F, G & N–P. Tamil Nadu population, H. German population.

FIGURE 3. Doryllium minor Jairajpuri, 1963. A–H. Anterior Uterine sac (A & B. Baramullah, C & D. Dachigam National Park, E & F. Ooty, G. Gudalur, H. Germany). I–P. Tail (I. Baramullah, J. Dachigam National Park, K. Kangan Valley, L. Nagaland, M. Ooty, N. Gudalur, O & P. Germany). A–D & I–K. Kashmir population, E–G & M–N. Tamil Nadu population, L. Nagaland population, H & O, P. German population.