Margollus turcicus, Ahmad, Wasim, Ahad, Sumaya & Sturhan, Dieter, 2013

Ahmad, Wasim, Ahad, Sumaya & Sturhan, Dieter, 2013, A new species of the rare nematode genus Margollus Peña-Santiago, Peralta & Siddiqi, 1993 (Nematoda: Tylencholaimoidea) from Turkey, Zootaxa 3646 (5), pp. 575-580 : 576-580

Margollus turcicus sp. n.

( Figs. 1 , 2 )

Measurements: Table 1

Description. Female: Medium-sized nematodes, slightly tapering towards the anterior end. Body slightly curved ventrad upon fixation. Cuticle with two distinct layers, 3–6 μm thick at mid body and 5–8 μm on tail; outer layer with fine transverse striation; inner layer two to three times thicker and more coarsely striated; radial refractive elements abundant. Lateral chords narrow, occupying about 16–20% of mid-body diameter. Dorsal and ventral body pores indistinct; lateral body pores usually distinct, more so in the posterior region of the body; four to five lateral pores on each body side within the range of the pharynx. Lip region rounded, tapering abruptly towards the anterior end, slightly offset from the body contour by a depression, 1.4–1.5 times as wide as high or about onethird of the body diameter at neck base; lips amalgamated; papillae indistinct. Cephalic framework with strong labial and post-labial sclerotization. Amphids well developed; fovea cup-shaped with sclerotized walls, its aperture located at the level of cephalic constriction and occupying more than two-thirds of lip region diameter. Stoma a truncate cone. Odontostyle 2.1–2.3 times the lip region diameter long and provided with dorsal accessory stiffening piece; its aperture one-ninth of the total length. Odontophore about 0.3 times the odontostyle length with distinct basal knobs, odontophore base 5–6 µm in diameter and 3 µm high. Guiding ring simple, 1.1–1.2 times lip region width from anterior end. Pharynx consists of a slender and weakly muscular anterior part and a short cylindrical or rarely pyriform posterior constricted basal bulb, which occupies about 16–19% of the total neck length, with two pairs of gland cells with nucleoli of almost equal size. Pharyngeal gland often visible. Cardia short conoid, 6–9 µm long. Nerve ring located at 51–52.5% of neck length from anterior end. Genital system monodelphicopisthodelphic. Ovary reflexed, 121–137 µm long, not reaching the oviduct-uterus junction; oocytes arranged in a single row except near the tip. Oviduct joining the ovary subterminally, 160–200 µm long and consisting of a slender distal part and a well developed pars dilatata, filled with spindle-shaped sperms of about 5 µm length. Oviduct-uterus junction marked by well developed sphincter. Uterus an undifferentiated tube, about 1.3–1.5 times the corresponding body diameter long. Anterior genital branch reduced to a simple sac, 0.5–1.2 times the mid body diameter long, occasionally filled with sperms. Vagina cylindrical; pars proximalis vaginae 8–13 µm long, its wall encircled by muscles; pars distalis vaginae short, 2–4 µm long with slightly curved walls. Vulva apparently a transverse slit. Prerectum 1.5–2.4 anal body diameter long. Rectum 0.5–0.6 times anal body diameter long. Tail short, hemispheroid, 0.6–0.7 anal body diameter long, with 1–2 pairs of lateral pores.

Male: General morphology similar to female. Genital tract diorchic with opposed testes. Sperms spindleshaped. Apart from the “adcloacal” pair only a weakly developed ventromedian supplement located at a distance of 27 µm from the adcloacal pair. Copulatory muscles weak. Spicules slender, long, cylindroid, slightly curved, 1.6 anal body diameters long. Lateral guiding pieces 7 µm long. Tail hemispheroid, 0.7 anal body diameter long. Caudal pores three pairs, one ventral, one subventral and a subdorsal pair.

Juveniles: In general morphological characteristics similar to females (cuticle layers, cephalic region, pharynx, tail shape etc.). Stylet length of J4 = 25–27 µm, of J3 = 22–24 µm.

Type habitat and locality: Loamy soil with stones from a vineyard at Tarsus, Turkey; collected at a soil depth of 60–70 cm on July 11, 1990.

Type specimens: Holotype female on slide Margollus turcicus sp. n. / 1; three paratype females and one male on slides M. turcicus sp. n. / 2–4; juveniles on slide M. turcicus sp. n. / 5. Holotype female, a paratype female and male deposited with nematode collection of the Department of Zoology, Aligarh Muslim University, India. Two paratype females and 14 juveniles deposited with the German Nematode Collection (DNST), Julius Kühn-Institut, Münster, Germany.

Etymology: The new species is named after its country of origin, Turkey.

Diagnosis and relationships: Margollus turcicus sp. n. is characterized by a medium-sized body (L=1.0– 1.2 mm); cuticle with distinct transverse striations; radial refractive elements abundant; lip region distinctly narrower than the adjoining body, slightly offset from the body contour by a depression; cephalic and labial papillae not discernable; strong labial and post-labial sclerotization present; amphids well developed with sclerotized walls; stylet 27–28.5 µm long, odontophore distinctly flanged, around 0.3 times the odontostyle length; pharyngeal bulb offset by a constriction, 33–37 µm long; female genital system mono-opisthodelphic, anterior branch 22–41 µm long, sac-like; spicules 49 µm long; single weak ventromedian supplement; tail in both sexes short hemispheroid.

In general morphology, the new species is very similar to the two known species of this rare genus, Margollus hispanicus (Peña-Santiago & Coomans, 1990) Peña-Santiago, Peralta & Siddiqi, 1993 and M. bellus Peña-Santiago, Peralta & Siddiqi, 1993 . It distinctly differs from both the previously known species by its characteristically smaller odontophore compared to odontostyle length (odontophore about 20% of the total stylet length in M. turcicus sp. n. vs more than 40% of total stylet length in both M. hispanicus and M.bellus ).

Moreover, the new species differs from M. hispanicus in having amphids well developed with sclerotized walls and occupying about two-thirds of the lip region diameter (vs amphid without sclerotized walls and occupying about half of the lip region diameter); odontostyle longer (21–22 vs 14–15 µm); odontophore shorter (6–7 vs 9–11 µm long; nerve ring located at 51–52.5% of the neck length (vs nerve ring located at 46–49% of the neck length); longer spicules (49 vs 42–46 µm) and presence of a ventromedian supplement (vs ventromedian supplement absent).

From M. bellus , the new species differs in having its lip region slightly offset from the body by a depression (vs anterior part of lip region offset by a constriction, appearing as a flat disc and posterior part continuous with body); labial sclerotization without hook-like anterior part (vs labial sclerotization with hook-like anterior part); amphids well developed with sclerotized walls and occupying about two-thirds of lip region diameter (vs amphids without sclerotized walls and occupying about half of lip region diameter); longer odontostyle (21–22 vs 12.5–13 µm); shorter odontophore (6–7 vs 7.5–9.5 µm); vulva slightly more posterior (V= 30.3–32.7 vs 26.9); female tail hemispheroid (vs tail convex conoid) and smaller c’ ratio (0.6–0.7 vs 1.02), and longer spicules (49 vs 33–36 µm).

Figures

FIGURE 1. Margollus turcicus sp. n. A; Entire male. B: Entire female. C: Anterior end. D: Anterior end showing amphid. E: Pharyngeal region. F & G: Expanded part of pharynx. H: Female genital system. I: Female posterior region. J: Male posterior region.

FIGURE 2. Margollus turcicus sp. n. A: Anterior end. B: Anterior end showing amphid. C: Expanded part of pharynx. D: Female genital system. E: Female posterior region. F: Female posterior end. G: Male posterior end (scale bar = 20 µm)

Tables

TABLE 1. Margollus turcicus sp. n. All measurements in µm, except L

Characters	Holotype female	Paratype females		paratype male
		Mean ± SD	Range
n	1	3		1
L (mm)	1.2	1.1 ± 0.53	1.08-1.21	1.1
Body width at neck base	38	36±2.3	34-40	35
Body width at mid body	41	38.4 ± 2.7	35-42	38
Body width at anus	32	34.8 ± 1.3	33-36.2	30
a	30.4	29.9 ± 0.8	28.7-30.6	30.9
b	5.9	5.8 ± 0.3	5.3 - 6.1	6.6
c	59.4	55 ± 8.7	48.5 - 67.3	55.9
c`	0.6	0.6 ± 0.05	0.6 - 0.7	0.7
V	32.2	31.6 ± 1.0	30.3 - 32.7
G1	3.2	2.8 ± 0.8	1.8 - 3.8
G2	20.2	20.2 ± 1.4	18.8 - 22.2
Lip region width	10	9.5 ± 0.5	9-10	11
Lip region height	7	6.5 ± 0.4	6-7	7
Amphid aperture	8	8.3 ± 0.4	8-9	8
Odontostyle length	22	21.3 ± 0.2	21.0-21.5	21
Odontophore length	6	6.6 ± 0.4	6-7	6
Guiding ring from anterior end	11	11	11	11
Nerve ring from anterior end	107	103 ± 1	102-104	104
Neck length	210	197 ± 3.3	194-202	179
Expanded part of pharynx	34	34.7 ± 1.6	33-37	34
Cardia length	9	7.3 ± 1.2	6-9	7
Anterior genital branch	40	32.4 ± 7.8	22-41
Posterior genital branch	253	233 ± 9.4	220-240
Vaginal depth	19	18.8 ± 1.4	17.0-20.5
Vulva from anterior end	402	365 ± 15.7	353-387
Prerectum length	50	73 ± 5.4	66.5-80.0	91
Rectum length	19	20.5 ± 1.5	19-22	27
Tail length	21	21.5 ± 3.8	16.0-24.5	21
Spicule length				49
Lateral guiding pieces				7
Ventromedian supplement				1