Trichodorus iranicus, Pedram, Majid & Pourjam, Ebrahim, 2014

Pedram, Majid & Pourjam, Ebrahim, 2014, Description of Trichodorus iranicus sp. n. (Diphtherophorina, Trichodoridae) from Iran, Zootaxa 3795 (4), pp. 431-440 : 433-435

Trichodorus iranicus sp. n.

( Figs 1–3 )

Measurements. Table 2 .

Male: Body cylindrical, tapering very slightly anteriorly, J-shaped after heat relaxation. Cuticle moderately swollen, 2–3 µm thick at onchiostyle region and 3 µm thick at mid-body and at anterior lip of anus. Lip region rounded, 8–9 µm wide. Amphidial fovea cup-shaped, its opening a wide slit. Stoma with refractive strengthening rods, approximately 5 µm long. Pharyngostom 42.5% of pharynx length, onchiostyle well developed, curved, onchium fine, 17–18 µm long, onchiophore well sclerotized, guiding ring at 3.5 times lip region width from anterior end. Pharynx composed of two parts: anterior slender part expanding gradually to form an offset terminal bulb, 20 µm wide×50 µm long, within which the dorsal gland nucleus and posterior pair of ventrosublateral nuclei are clearly visible, while the anterior pair of ventrosublateral nuclei are much smaller and more difficult to discern. Cardia slightly to moderately developed. Nerve ring 7.5–11.5 µm posterior to the base of pharyngostom. Three distinct cervical papillae present, the anteriormost (CP1) located at about 50–60% of pharyngostom length, the second papilla (CP2) at ca. 5 µm anterior (in paratype male) or posterior (holotype) to the pharyngostom base and the third papilla (CP3) at or slightly posterior to the middle of the isthmus. Secretory-excretory pore at 13.5–16.0 µm posterior to CP3, opposite the isthmus. Reproductive system monorchic, sperm cells with large sausage-shaped nuclei, spicules ventrally curved, slightly sclerotized, their proximal part widened with slightly developed capitulum, middle part indented and provided with a few bristles (two dorsal and two on ventral side in holotype), gubernaculum short. Three precloacal supplements (SP), with the posteriormost (SP1) located anterior to the proximal end of the spicules. Tail rounded, its length less than one body width at cloacal region, one pair of small postcloacal subventral papillae situated just posterior to the cloacal opening, subventral pair of caudal pores at a short distance from them. Hyaline part of tail 7–9 µm thick.

Female: Body straight, cigar-like. General morphology similar to that of male, except for the reproductive system, and with the posterior body region not ventrally curved. Excretory pore opposite isthmus. Anterior and posterior genital tracts of more or less equal length, each with a spermatheca containing sperm cells near the oviduct at the reflexed tip of the ovary. Morphology of sperm cells similar to mature sperm in genital tract of the male. Vagina well developed, 46–57% of corresponding body width in length, pars proximalis vaginae more or less rhomboid, pars refringens vaginae triangular to rounded-triangular, medium sized (ca. 3.5 µm), 1–2 µm apart from each other; vulva a transverse slit in ventral view. One female with copulatory plug at vulva-vagina level.

Post-advulval body pore 33 µm (n=1) posterior to vulva. Tail short, 3–5 µm in length, and rounded. Caudal pores subventral, just posterior to anus.

Juveniles: Some damaged juveniles were found, but were in poor condition and not suitable for morphological study.

Code, using the polytomous identification key of Decraemer & Baujard (1998):

For male: A = 222 (mean, min, max), B = 22, C = 11, D = 33, E = 12, F = 3, G = 0, H = 20, I = 11, J = 500, K = 33, L = 44, M = 160, N = 11, O = 1, P = 2; for female: A = 200, B = 22, C = 1, D = 1, E = 200, F = 100, G = 2, H = 22, I = 23, J = 11, K = 400, L = 22, M = 1, N = 2, O = 11, P = 11, Q = 1, R = 1, S = 7.

Type habitat and localit y. Soil samples collected from the rhizosphere of grasses in forests of Golestan province, GPS coordinates: N36°34.942, E051°49.166.

Type material. Holotype male and three paratype females deposited in the Nematode Collection of the Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran. One paratype male and two females in the USDA Nematode Collection, Beltsville, MD, USA.

Figures

FIGURE 1. Trichodorus iranicus sp. n. A – C: Pharynx region; A: Female, B & C: Males, D: Part of female reproductive system, E & F: Tail of female, G: Male reproductive system, H – J: Variation in morphology of vagina and its parts (K: Copulatroy plug), L & M: Spicules.

FIGURE 2. Trichodorus iranicus sp. n. A: Pharynx region of male showing three cervical papillae (three upper arrows) and excretory pore (lower arrow), B: Male posterior end showing spicule, C: Bristles in mid – region of spicules, D: Male posterior body region (All scale bars = 10 µm).

FIGURE 3. Trichodorus iranicus sp. n. A: Pharynx region of female, B & C: Part of pharynx, showing pharyngeal bulb and excretory pore (B, arrow), D – F: Female tails, G – K: Vagina and vulva morphology; G: Copulatory plug, K: Vulval opening (All scale bars = 10 µm).

Tables

TABLE 2. Morphometrics of Trichodorus iranicus sp. n. All measurements are in Μm and in the form: mean ± s. d. (range).

Character	Holotype	Paratypes
	Male	Male Females
n	1	1 5
L	844	942 813.6±54.6 (727–870)
a	31.3	25.5 26.6±0.8 (26.0–27.5)
b	5.3	5.9 5.3±0.2 (5.1–5.6)
c	56.3	55.4 –
V	–	– 60.3±1.5 (59.2–63.0)
Ant–vulva	–	– 490.4±38.3 (433–532)
Onchiostyle	59	59 56.8±2.8 (54–60)
Pharyngostom	68	68 67.5±2.1 (65–70)
Pharynx	160	160 154.6±10.6 (143–171)
Anterior end to guiding ring	26	25 25.0±1.6 (23–27)
Anterior end to nerve ring	78	74 75.8±6.0 (70–84)
Anterior end to excretory pore	109	105 100±7 (95–105)
Anterior end to CP1	45	35 –
Distance of CP1 to CP2	28	26 –
Distance of CP3 to excretory pore	14	15 –
Body width at cardia	28	33 26.5±1.7 (25–29)
Body width at midbody	27	37 30.5±1.7 (28–32)
Body width at anus/cloaca	23	29 –
Spicule length	28	30 –
Gubernaculum	14	11 –
Distance of SP1 to cloacal opening	32	29 –
Distance of SP1 to SP2	28	33 –
Distance of SP2 to SP3	51	50 –
Length of anterior genital tract	–	– 138.7±12.2 (128̶152)
Length of posterior genital tract	–	– 142.0±14.5 (130̶158)
Length vagina	–	– 13.7±0.6 (13̶14)
Vagina ingrowth (% to midbody diam.)	–	– 45.7±3.8 (43.5̶50.0)
Distance between sclerotised pieces	–	– 1.5±0.7 (1̶2)
Sclerotised pieces	–	– 3.5±0.0 (3.5̶3.5)
Tail	15	17 –