Dorylaimoides alborzicus, Pedram, Majid, Pourjam, Ebrahim & Vinciguerra, Maria T., 2011

Pedram, Majid, Pourjam, Ebrahim & Vinciguerra, Maria T., 2011, Description of Dorylaimoides alborzicus sp. n. (Dorylaimida: Nematoda) from Iran, with updated compendium and key to the species of Dorylaimoides, Zootaxa 3022, pp. 58-68 : 59-63

Dorylaimoides alborzicus sp. n.

( Figs 1 and 2 ; Table 1)

Female. Slender nematodes of medium size. Body in the shape of an open C after fixation, tapering gradually towards both ends, more pronounced anteriorly. Cuticle with very fine transverse striations, 1–2 µm thick between anterior end and odontophore base, 2 µm at mid body and 2.5–3.0 µm at anus level. Lateral chords 3.5–4.5 µm wide or 11.0–13.5% of corresponding body width. Lip region 2.1–2.3 times as wide as high, separated from the rest of body by a sharp constriction. Amphids cup-shaped; their slit-like aperture corresponding to 71–75% of lip region width. Odontostyle typical of genus, asymmetrical, 1.5 µm thick at base; its aperture 1.5–2.0 µm long. Odontophore arcuate, about 1.5 times as long as odontostyle. Guiding ring simple. Nerve ring located 90–103 µm from anterior end. Anterior part of pharynx narrow and weakly muscular, posterior expanded part composed of a 50–62 × 12–14 µm sized terminal bulb, occupying 25–28% of total neck length. Gland nuclei located as follows (n=3): DN: 79.5–82.0, AS 1 and AS 2 almost at same level: 23–30 and PS1 and PS2 at same level: 46.5–52.5. Cardia conical; body width at this level 3.0–3.6 times as wide as lip region width. Female reproductive system monoopisthodelphic; its anterior branch a uterine sac 37–61 µm long or 1.1–1.7 times body width; vagina cylindrical, extended inward for 15–23 Μm, about 50.0–54.5% of corresponding body width; its wall adjacent to the vulva not clearly distinct from the body cuticle.Vulva a transverse slit. Posterior genital tract 204–310 µm long, composed of a 60–80 µm long ovary, 120–176 µm long oviduct with a well developed pars dilatata, a well developed sphincter and a 70–83 µm long, thin-walled, simple uterus containing sperm with dimensions of 5.0×1.5 µm; one 92×26 µm uterine egg observed. Prerectum 60–107 µm long or 2.8–5.4 times anal body width and rectum 20–25 µm long or 1.0–1.3 times anal body width. Tail straight to ventrally bent, elongate conoid with rounded terminus, characterised by a very thick cuticle and a thin internal core, 2.3–3.0 anal body widths in length.

Male. Abundant, equal to females in number and functional. Similar to females in general morphology except for reproductive system and by having the posterior end more ventrally bent. Spicules dorylaimoid, 4.7–5.5 times longer than wide with 7–8 µm long lateral accessory pieces. Male copulatory supplements composed of one precloacal pair at a distance of 8–11 µm from cloacal opening and a series of 5–6 ventromedian supplementary papillae extending 16–26 µm from cloacal pair. Tail conoid, ventrally bent with rounded end.

Differential diagnosis and relationships. Dorylaimoides alborzicus sp. n. is an amphimictic species with functional males in this population. It is characterised by having the lip region separated from the rest of body by a sharp constriction, body length of 1.1–1.3 mm, 10–11 µm long odontostyle (from tip of ventral arm to end of dorsal arm), 15–16 µm long arcuate odontophore, opisthodelphic genital system with anterior uterine sac 37–61 µm long or 1.1–1.7 times body width, tail 46–62 µm long (2.3–3.0 times anal body width), straight to slightly ventrally bent, elongate conoid with rounded terminus, with a very thick cuticle and a thin internal core tail; males with 31–35 µm long spicules, 5–6 ventromedian supplements and ventrally bent tail, 39–60 µm long.

The new species resembles 8 other opisthodelphic species of Dorylaimoides with conoid tails: D. arcuatus Siddiqi, 1964 , D. bulbosus ( Brzeski & Szczygiel, 1961) Szczygiel, 1965 , D. modestus Siddiqi, 1965 , D. reversus Thorne, 1964 , D. saueri Baqri & Jairajpuri, 1969 , D. singaporensis Ahmad & Mushtaq, 2004 , D. uralicus ( Nesterov, 1976) Andrássy, 2009 , and D. venustus Andrássy, 1959 .

Compared to D. arcuatus , the new species has a somewhat longer body (L = 1.1–1.3 vs. 0.7–1.2 mm), shorter tail (c = 19.0–24.5 vs. 10–20), longer odontostyle (10–11 vs. 4.5–7.0 µm long), tail straight or slightly ventrally arcuate vs. markedly ventrally arcuate and longer spicules (31–35 vs. 20–29 µm). Compared to D. bulbosus , the new species has a lip region separated from the rest of body by a sharp constriction vs. not set off, anterior uterine sac 1.1–1.7 times the corresponding body width vs. about 2, longer odontostyle (10–11 vs. 8.0–8.5 µm), and functional males. Compared to D. modestus , the new species has a longer body (L = 1.1–1.3 vs. 0.72–0.85 mm), lip region separated from the rest of body by a sharp constriction vs. almost continuous, shorter tail (c = 19.0–24.5 vs. 12.0–13.5) and presence of males. Compared to D. reversus , the new species has a longer body (L = 1.1–1.3 vs. 0.8 mm), shorter tail (c = 19.0–24.5 vs. 13), straight to ventrally curved in females vs. dorsally bent. Compared to D. saueri , the new species has longer body (L = 1.1–1.3 vs. 0.8–0.9 mm), shorter tail (c = 19.0–24.5 vs. 9–13; c’ = 2.3–3.0 vs. 5–6) and longer spicules (31–35 vs. 19–22 µm). Compared to D. singaporensis , the new species has a longer body (L = 1.1–1.3 vs. 0.78 mm), longer odontostyle (10–11 µm dorsal arm vs. 5–6 µm) and longer spicules (31–35 vs. 21–22 µm). Compared to D. uralicus , the new species has a shorter tail (46–62 vs. 69.5 – 92.0 µm; c = 19.0–24.5 vs. 16.1–16.3;) with thin cuticle and thick core, and with males present. Compared to D. venustus , the new species has a lip region separated from the rest of body by a sharp constriction vs. slightly offset, longer odontostyle (10–11 vs. 6–7 µm), smaller b value (5.0–6.5 vs. 6.8–8.8), shorter tail (c = 19.0–24.5 vs. 17.8–19.8; c’ = 2.3–3.0 vs. 4.2–5.0), and more posterior vulva (V = 34.7–36.5 vs. 33.1–33.7).

Etymology. The specific epithet refers to the Alborz Mountains, the locality in northern Iran where the species was found.

Type habitat and locality. Dorylaimoides alborzicus sp. n. was recovered from soil samples collected about the rhizosphere of unidentified species of grasses growing at 2946 m above sea level altitude, in Azad Kooh, Alborz Mountains, north of Iran, during May 2010.

Type specimens. Holotype female, five paratype females and two paratype males deposited in the nematode collection of Tarbiat Modares University, Tehran, Iran. Two paratype females and two paratype males deposited in the nematode collection of the Department of Biology, University of Catania, and two males and two females in separate slides deposited in USDA Nematode Collection, Beltsville, MD, USA.

Character Holotype female Females Males n - 9 8

L (µm) 1229 1199±65 1176±70 (1106–1303) (1041–1251) a 37.2 37.0±2.3 37.3±4.0 (33.7–39.5) (31.5–43.0) b 6.1 5.7±0.5 5.7±0.3 (5.0–6.5) (5.2–6.0) c 23.2 21.5±1.7 22.0±2.2 (19.0–24.5) (20.3–26.7) c`2.5 2.7±0.2 2.4±0.2 (2.3–3.0) (2.1–2.7) V 35.8 36.0±0.5 -

(34.7–36.5) -

Lip region diam. 8.5 8.5±0.5 8.3±0.5 (8–9) (8–9)

Odontostyle dorsal line 10.0 10.5±0.5 10.0±0.5 (10–11) (9.5–10.5) Odontostyle ventral line 9.0 9.3±0.7 8.5±0.5 (8–10) (8.0–9.5) Odontophore 15.0 15.0±0.5 16.0±0.5 (15–16) (15.0–16.5) Guiding ring from ant. end 6.5 7.3±0.5 7.6±0.5 (6.5–8.0) (7.0–8.5) Neck length 200.0 211±14 207.5±10.5 (190–232) (192.5–222.0) Anterior end to vulva 440.0 429±17 -

(400–457) -

continued next page Character Holotype female Females Males Body width. at: neck base 30.0 29±1 28.5±1.5 (27–30) (27–31) mid-body 33.0 33±1 31.7±2.0 (31–34) (29–34) anus 21.0 21±1 22.0±1.5 (20–22) (19–23) Tail length 53.0 56.5±5.0 52.5±6.5 (46–62) (39–60) Spicule length - - 33.0±1.5 - (31–35)

Number of male VM supplements - - -

- (5–6) Lateral accessory pieces - - 7.5±0.5 - (7–8) Cardia length 8.0 9.7±1.5 9.7±1.5 (8–12) (8–11) Cardia width 8.0 8.5±0.5 9±1 (8–9) (8–10)

Figures

FIGURE 1. Dorylaimoides alborzicus sp. n. A: Neck region, B: Reproductive system of female, C: Posterior end of male, D – F: Common tail shape in females, G: Anterior end in detail, H: Spicules and lateral accessory pieces, I & J: Entire body; I: Male, J: Female.

FIGURE 2. Dorylaimoides alborzicus sp. n. A & B: Entire body; A: Male, B: Female, C & D: Female anterior end; C: Lateral view, D: Ventral view, E: Posterior genital tract, F: Anterior uterine sac, G: Posterior end of male, H & I: Female tail, J: Tail tip.