Pratylenchoides persicus, Azizi, Kourosh, Eskandari, Ali, Karegar, Akbar, Ghaderi, Reza, Elsen, Sven Van Den, Holterman, Martijn & Helder, Johannes, 2016

Azizi, Kourosh, Eskandari, Ali, Karegar, Akbar, Ghaderi, Reza, Elsen, Sven Van Den, Holterman, Martijn & Helder, Johannes, 2016, Morphological and molecular characterization of Pratylenchoides persicus n. sp. (Nematoda: Merliniidae) and additional data on two other species of the genus from Iran, Zootaxa 4205 (5), pp. 459-474 : 461

Description of Pratylenchoides persicus n. sp.

( Figures 1 & 4 ; Tables 1 & 2 )

Female. Body slightly curved ventrally after heat fixation. Cuticle with distinct annuli, 1.5–1.8 µm wide at midbody; lateral field with six longitudinal incisures at deirid and mid-body, and four incisures at post-phasmid, the outer bands areolated at posterior part of pharynx, 7.0–8.8 µm wide and occupying 31–38 % of the body width at mid-body. Lip region off-set by slight depression with body contour, rounded anteriorly or slightly flattened and bearing four or five distinct but fine annuli, 9.4–10.3 µm wide at base and 3.6–4.1 µm high ( Fig. 1 B–D and 4 A & B). Stylet strong with rounded or posteriorly flattened basal knobs; the conus 9.0–11.2 µm long or half of the total stylet length. Dorsal pharyngeal gland orifice located 3–4 µm behind the stylet knobs. Median bulb oval, 13–19 µm long and 10.0–12.3 µm wide with refractive valves. Deirids at the level of hemizonid or slightly anterior to it. Secretory-excretory pore located in anterior half of the pharyngeal glands or 110–126 µm from the body anterior end; hemizonid 2–4 annuli anterior to secretory-excretory pore. Pharyngeal glands abutting or slightly overlapping intestine dorsally; all three nuclei of dorsal and subventral glands located anterior to the pharyngo-intestinal valve ( Fig. 1 C–D and 4 F–H). Intestinal fasciculi visible in some specimens. Reproductive system didelphic, amphidelphic; spermatheca rounded, filled with globular sperm. Vagina 9–12 µm long and 40–50 % of the body width at vulva. Tail cylindrical, with truncate to low rounded and coarsely annulated terminus. Hyaline thickness 7–10 µm. Phasmids located 21–30 µm posterior to anus, in the posterior half of the tail ( Fig. 1 J–L and 4 L–N).

Male. Similar to female in general view. Body slightly curved ventrally. Lateral field with six incisures; outer band areolated. Lip region high, rounded or slightly flattened. Stylet slightly more slender than that of females ( Fig. 1 E & F and 4 C & D). Spicules curved ventrally, gubernaculum simple. Tail conical, tapering gradually to a conoid or more or less subcylindrical terminus ( Fig. 1 M–N and 4 O).

Diagnosis and relationships. Pratylenchoides persicus n. sp. is characterized by a lip region rounded anteriorly or slight flattened and bearing four or five fine annuli, pharyngeal glands abutting or slightly overlapping intestine dorsally, all the three gland nuclei located anterior to the pharyngo-intestinal valve and tail cylindrical with truncate to low rounded terminus. This species comes closest to P. heathi Baldwin, Luc & Bell, 1983 ; P. sheri Robbins, 1985 ; P. arenicola Ryss & Sturhan, 2001 ; P. laticauda Braun & Loof, 1967 and P. erzurumensis Yüksel, 1977 . In comparison with the original description of P. heathi ( Baldwin et al. 1983) , the new species can be separated by shorter body length (601–784 vs 820–1330 µm), smaller stylet (19.7–22 vs 23.5–27.5 µm), shorter tail (35–46 vs 44–69 µm) and different shape of tail terminus (truncate to low rounded vs rounded) in females, as well as a smaller stylet (19.8–20.9 vs 23.5–27 µm) in males. P. persicus n. sp. has a shorter body than P. sheri (601–784 vs 898–1173 µm), a shorter stylet (19.7–22 vs 22–25.5 µm), a shorter pharynx (154–194 vs 190–217 µm), and a shorter tail (35–46 vs 47–64 µm) in females. Furthermore, P. persicus n. sp. males have a shorter stylet (19.8–20.9 vs 21.5–24 µm) and spicules (21.7–27 vs 28–31 µm). P. persicus n. sp. differs from P. arenicola in the shape of tail terminus in males (usually conical vs cylindrical), as well as a shorter stylet (19.7–22 vs 25 µm in females and 19.8–20.9 vs 23–25 µm in males), also in body length (601–784 vs 980–1100 µm in females and 623–665 vs 800– 890 µm in males). The other two related species, P. laticauda and P. erzurumensis , have a longer overlap of the pharyngeal glands with the intestine (vs abutting or very short overlapping), posterior position of the subventral gland nuclei to the cardium (at least one of the subventral gland nuclei close to the cardium vs all the three nuclei distinctly anterior to the cardium), different glands shape (saccate vs elongate-cylindrical) and a smaller number of head annuli (usually 3 wide annuli vs 4 or 5 fine annuli). Furthermore, males of P. erzurumensis have a conoid lip region which is different from that of females (rounded or flattened, similar to that of females, in P. persicus n. sp.).

Type material. Holotype female (slide number KA1100), eight paratype females and three males and five juveniles on slide numbers KA1101-KA1105 kept in the nematode collection of Department of Plant Protection , College of Agriculture, University of Zanjan, Iran ; two female paratypes, two males and one juvenile on slide numbers WT3668 and WT 3669 in the Nematode Collection of Plantenziektenkundige Dienst, Wageningen, The Netherlands .

Type habitat and locality. The specimens were collected by the second author (Ali Eskandari) from the rhizosphere of oregano ( Origanum vulgare L.) in Abr forest, Shahrud county, Semnan province, northern Iran (GPS coordinates: N 37° 45' 385"– E 55° 02' 287"), May 2014.

Etymology. The species epithet refers to the Latin name of Iran, the country where it was recovered and identified.

Figures

FIGURE 1. Pratylenchoides persicus n. sp.; A – D & H – L: females; E – G & M – N: males. A & G: Entire body; B: Anterior end; C – F: Pharyngeal region; H & I: Lateral field; J – N: Tail.

FIGURE 4. Photomicrographs of Pratylenchoides persicus n. sp. females (A – B & E – N) and males (C – D & Q). A, D: head and stylet. E: Pharynx. F – H: Pharyngeal glands and position of their nuclei. I: Deirid. J: Lateral field. K: Spermatheca. L – Q: Tail. Scale bars = 10 µm. (a = anus; c = cardia; d = deirid; n = pharyngeal gland nuclei; ph = phasmid; s = spermatheca).