Dorylaimus

Sen, Debabrata, Chatterjee, Amalendu & Manna, Buddhadeb, 2012, One new and two known species of Dorylaimoidea (Nematoda) from West Bengal, India, Zootaxa 3258, pp. 46-57 : 54-56

Dorylaimus sp.

( Figure 4 )

Measurements: See Table 3 .

Females. Body almost straight or slightly ventrally curved in posterior half on fixation, tapering gradually towards both extremities. Cuticle finely striated, marked with longitudinal ridges, 3.5–7.5 Μm thick at midbody and 9.5–11.5 Μm thick on tail. Lip region almost continuous or superficially marked by depression, lips amalgamated, 5–8 Μm high and 14.5–16.5 Μm wide or 16–21% of body width at pharyngeal base. Amphids stirrup-shaped, at 6– 8 Μm from anterior end. Odontostyle 2–2.8 lip-region widths long, 5–7 Μm thick, aperture 13–18 Μm or 39–43 % of odontostyle length. Guiding ring double, 19.5–23.5 Μm from anterior end. Odontophore about 0.8–1 times the odontostyle length. Nerve ring at 157–181 Μm from anterior end. The length of the expanded portion of pharynx (cylindrus) 49–50% of total pharyngeal length. Glandularium 91–97 % of the cylindrus. Cardia tongue-shaped, conoid with rounded tip posteriorly. The location of pharyngeal gland nuclei: D = 50.3–52.1%, AS 1 = 43.9%, AS 2 = 51.2%, PS1 = 66.1–78.7%, PS2 = 71–82.4%. Vulva transverse, pre-equatorial. Vagina 24–26Μm or 36–37% of the vulval body width long. Length of pars proximalis vaginae 14.7–17.5Μm, with slightly sigmoid walls, pars refringens 4–5Μm long, sclerotised pieces almost oval or sometimes triangle-shaped and pars distalis vaginae 3.0– 4.0Μm long. Reproductive system didelphic-amphidelphic, with both genital branches equally well developed, anterior branch slightly longer than the posterior: anterior branch 345.5–392Μm and the posterior branch 345.5– 372.5Μm long. Ovaries large, reflexed, sometimes surpassing the sphincter level, anterior ovary 98–147Μm long and posterior ovary 110–147Μm long. Oocytes arranged in a single row except at the terminal growth region. Oviduct long, tubular, often with visible lumen, joining the ovary subterminally. Indistinct and weakly developed sphincter separating oviduct from uterus, but not very marked. Uterus, tubular, muscular, short and simple with thick wall and often with distinct lumen. Prerectum 2.2–3.5 anal body-width, rectum 0.8–1.4 anal body-widths long. Tail elongate conoid with finely rounded terminus, 4.6–8.4 anal body-widths long.

Male. Similar in morphology to females except for the following: Odontostyle and odontophore slightly longer than in females. Testes outstretched. Spicules 1.5 anal body-widths long. The supplements consist of an adanal pair and 36 contiguous ventromedians. Tail short, bluntly rounded, less than 1 anal body-width in length.

Habitat and locality. Collected from the soil around the roots of guava at Shalipur (West) and Balarampur of Baruipur block on 12.06.2004 and from Falta block (latitude 22.29° east and longitude 88.12° north) on 0 9.06.2007.

Remarks. Baqri and Jana (1986) described Dorylaimus geraerti from the soil around roots of brinjal ( Solanum nigrum L.) from Narendrapur, South 24-Parganas, near the collection site for these specimens, within the same block. The present specimens fit well with the type specimens of D. geraerti except for the b value (4.2–5.1 vs. 4.3–4.7), length of odontostyle, odontophore, prerectum and tail length in females (33–42 vs. 43–47 Μm, 33–49Μm vs. 40–43Μm, 120–160 vs. 196–241 Μm, 247.5–294 Μm vs. 249–406 Μm in females, respectively). Although Dorylaimus sp. differs from Dorylaimus geraerti in odontostyle and odontophore length, the odontostyle-lip region ratio (2–2.8 vs. 2.4–2.6) and odontophore-odontostyle ratio (0.8–1 vs. 0.9–1) are almost in the same ranges. In the male paratypes of D. geraerti , there are 35–38 supplements, mostly contiguous, but with 4–5 spaced supplements in the middle of the series. Baqri and Jana (1986) concluded that D. geraerti is similar to the genus Ischiodorylaimus Andrássy, 1969 in having sets of both contiguous and a few spaced supplements, but they placed it under the genus Dorylaimus Dujardin, 1845 due to its shorter body and the ventromedian supplements not being arranged in two distinct groups. The present male specimen differs in arrangement of ventromedian supplements in having the contiguous supplements without any spaced ones but the number of supplements is within the range of D. geraerti . In spite of resemblance and closeness with D. geraerti , the present specimens are designated as Dorylaimus sp. without creating a new species until and unless more male specimens are available and can be examined.

Figures

FIGURE 4. Dorylaimus sp. Female. A. Anterior end, B. Pharyngo- intestinal junction and cardia, C. Anterior branch of gonad, D. Tail Male. E. Anterior end, F. Posterior end showing ventromedian supplements, spicule & tail.

Tables

TABLE 3. Morphometrics of Dorylaimus sp. (All measurements are in Μm except L and body ratios, L in mm; Mean ± SD (Range)].

Characters	Females	Male
n	10	1
L	3.0 ± 0.2 (2.9–3.3)	2.8
a	35.7 ± 6.3 (27–41.4)	29.3
b	4.9 ± 0.1 (4.7–5.1)	4.2
c	11.4 ± 1.4 (9.9–13.2)	84.6
c’	6.4 ± 1.6 (4.6–8.4)	0.6
V %/ T%	42.5 ± 1.7 (39.8–44.1)	63
G1%	12.5 ± 0.8 (11.7–13.4)	--
G2 %	12.4 ± 0.6 (11.7–12.8)	--
Odontostyle length	37.4 ± 4.3 (33–42)	48
Odontophore length	40.8 ± 6.0 (33–49)	54
Maximum body width	89.1 ± 23.3 (71–122.5)	98
Body width at neck base	93.5 ± 20.9 (71–120)	98
Body width at vulva	93.1 ± 24.8 (71–122.5)	--
Pharynx length	620.2 ± 57.7 (563.5–686)	674
Expanded part of pharynx	313.5 ± 26.1(294–348)	348
Glandularium	273.0 ± 10.4 (266.5–285)	--
Length of anterior gonad	366.7 ± 23.5(345.5–392)	--
Length of posterior gonad	363.3 ±15.4 (345.5–372.5)	--
Anterior end to vulva	1306.2 ± 57.8 (1249.5–1401.5)	--
Tail length	268.5 ± 21.7 (247.5–294)	34
Anal body width	43.5 ± 9.6 (34–54)	53
Length of prerectum	130.4 ± 16.8 (120–160)	--
Length of rectum	48.5 ± 1.1 (46.5–49)	--
Total length of testis	--	1815.5
Length of spicules	--	81
Ventromedian supplements	--	36