Paractinolaimus persicus, Panahi & Shokoohi & Clausi & Mashela, 2019

Panahi, Hadi, Shokoohi, Ebrahim, Clausi, Mirella & Mashela, Tu. W., 2019, Paractinolaimus persicus sp. n. (Nematoda: Actinolaimidae) from Iran, Zootaxa 4551 (2), pp. 244-250 : 245-249

Paractinolaimus persicus sp. n.

( Figs. 1–3 )

Measurements: Table 1.

Adult: Body straight or slightly curved after fixation. Cuticle thickness 2.9–3.8 µm in anterior part, 3.8–4.3 µm in mid body and 5.8–6.8 µm in posterior part of the body. Lip region rather low, slightly offset from the adjoining body, anteriorly truncate, with laterally rounded sides, 2.7–2.8 times as wide as high; two circles of six inner and six outer labial papillae are slightly visible but not prominent. Lip region provided with a corrugated vestibular ring. Amphids stirrup-shaped, with a slit like opening occupying 38–44% of lip region diameter. Buccal cavity wall strongly sclerotized; four massive, acuminate onchia start from the wall to surround the odontostyle, each appearing first as a thin lamina and then, in proximity of the odontostyle, very thick and sclerotized. The stomal wall and the onchia are covered with tiny, sparse denticles. Odontostyle massive, about 1.2 times the lip region diameter long and 8.3–9.5 times as long as wide, with aperture occupying 45–56% of its length. Odontostyle width 0.75–1.0 times the cuticle at the same level. Odontophore rod-like, simple, 1.9–2.1 times the odontostyle length. Guiding ring “double”, fixed ring at 18.4–19.4 µm from anterior end. Two body pores present dorsally at odontostyle level in one specimen. Pharynx consisting of a slender but muscular anterior region, with a slight constriction 50–57 µm behind the base of odontostyle, and a posterior expanded part; the glandularium occupies 52–53% of neck length; pharyngeal gland nuclei located as follows (n = 5): D = 47–54, AS 1 = 62–70, AS 2 = 68– 70; PS = 75–89%. Nerve ring at 24–26% of neck length. Cardia consisting of a discoid, partly glandular section between pharynx and intestine, and a conoid part projecting into the latter. Prerectum 2.0–2.2 times and rectum 0.4–0.6 times as long as anal body diameter.

Female. Reproductive system didelphic amphidelphic, well developed, with anterior and posterior branches of similar length, each composed of reflexed ovary, 165–307 µm long, oocytes arranged first in one and then in two rows, oviduct with a small pars dilatata and uterus bipartite, 152–311 µm long: distal part with very narrow lumen and proximal part enlarged. Eggs two to four in the uterus, 46–49 × 76–85 µm in dimension. No sperm observed in the uterus. A sphincter is present at the junction between uterus and oviduct. Vagina occupying about 0.4–0.6 of corresponding body width: pars proximalis cylindroid, pars refringens about 1.4–1.5 times as wide as long and composed of two pieces, square to triangle shaped, each 3–4 µm × 2–3 µm in dimension, and pars distalis short. Vulva a small oval pore, appearing longitudinal in profile view. No advulval papillae present in any of the specimens examined. Tail elongate filiform (c’ = 3.3–5.9), curved ventrad, with pointed terminus.

Male: Body “J” shaped after fixation with posterior body region more curved ventrad than in female. Genital system diorchic, with opposed testes. In addition to the pre-cloacal pair, there is a series of 17–18, contiguous, ventromedian supplements starting at 84–96 µm from cloacal opening, the most anterior of which is 177–200 µm apart from cloacal opening. Distance between two each contiguous supplement 3.9 µm. No copulatory hump observed. Spicules massive, 1.6 times the cloacal body diameter long. Tail convex conoid with blunt terminus. Prerectum 6.2 times as long as the anal body diameter. Only two pairs of caudal pores clearly visible in the male specimens.

Diagnosis: The new species is characterized by having body 2.3–2.6 mm long; low, truncate lip region; four massive, acute onchia; stoma walls covered with sparse tiny denticles; odontostyle 25–28 µm long; well developed, didelphic-amphidelphic female reproductive apparatus; vulva a longitudinal oval pore; absence of advulval papillae; female tail elongated filiform (c’ = 3.3–5.9), curved ventrad, and with acute terminus; mail tail convex conoid with blunt terminus; 17–18 contiguous ventromedian supplements.

Relationships: Paractinolaimus persicus sp. n., among the numerous species of Paractinolaimus described so far, and according to Vinciguerra et al. (2013), in its morphometrics mostly resembles P. baldus Thorne, 1967 , P. intermedius Altherr, 1968 , P. decraemerae Pedram, Niknam, Vinciguerra, Ye & Robbins, 2010 and P. chandicus Khan & Jairajpuri, 1994 . This species differs from P. baldus in the value of a (32–35 vs 46), c (11.6–16.9 vs 11), c’ (3.3–6.0 vs 8.7) and in the supplement number (17–18 vs 10–11). From P. intermedius it differs in relative tail length (c’ = 3.3–5.9 vs 6–7), absence of advulval papillae (vs presence) and spicule length (71.0–75.5 vs 63–65 µm). The new species differs from P. decraemerae in body length (2.3–2.6 mm in females and 2.1–2.6 mm in male vs 2.8–3.2 mm in females and 2.1 mm in male), with rather shorter female tail (146–224 µm vs 200–238 µm), in the much more posterior pharynx subventral gland nuclei ( AS = 62–70 vs 48.5–52; PS = 75–89 vs 67–69), in the more rounded eggs (46– 49 x 76–85 µm vs 35– 42 x 80–105 µm) and by always lacking advulval papillae vs one anterior and one posterior always present in P. decraemerae . From P. chandicus , the new species mainly differs in the number of ventral supplements (17–18 vs 11) and spicule length (71.0–75.5 µm vs 60 µm).

Type material: Female holotype and one male paratype deposited at the Nematology laboratory, University of Limpopo, South Africa. Three female paratypes deposited at Nematology Diagnostic laboratory, Khosrow-Shirin, Fars Province, Iran .

Etymology: The species is named in honour of the country, Persia, which is the former name of Iran, where the species has been found.

Figures

FIGURE 1. Paractinolaimus persicus sp. n. A: Neck. B: Anterior end. C: Entire female. D: Entire male. E: Female reproductive system. F: Female posterior end. G: Cardia. H: Male posterior end.

FIGURE 2. Paractinolaimus persicus sp. n. (LM) A, B: Anterior end (in B arrows indicating the body pores). C: Entire male. D: Entire female. E: Pharyngeal intestinal junction. F: Eggs. G: Female posterior end. H: Vagina. I: Male posterior end and ventromedian supplements. J: Spicules [scale bar: 10 µm except for C and D: 100 µm].

FIGURE 3. Paractinolaimus persicus sp. n. (SEM) A–C: Anterior end. D: Anus. E: Female posterior end.