Pratylenchoides cf. nevadensis Talavera & Tobar, 1996

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 : 466-471

Iranian population of Pratylenchoides cf. nevadensis Talavera & Tobar, 1996

( Figures: 3 & 6 ; Table 4 )

Female. Body slightly curved ventrally to C-shaped after heat fixation. Cuticular annuli 1.3–1.7 µm wide at midbody. Lateral field with four or six longitudinal incisures at mid-body, with always four at the deirid and in the post-phasmid portion of the body; occupying 34–41 % of the body width at mid-body. Lip region off-set by slight depression with the body contour, rounded anteriorly or slightly flattened and bearing three-four distinct annuli, 8.8–11.0 µm wide at base and 3.2–4.0 µm high ( Fig. 3 C–E and 6 A & B). Stylet with rounded knobs. Dorsal pharyngeal gland orifice located 2–3 µm behind stylet knobs. Deirids at the level of hemizonid or slightly anterior to it. Secretory-excretory pore located 88–125 µm from the body anterior end; hemizonid 2–3 annuli anterior to the pore. Pharyngeal glands overlapping intestine dorsally for 30–56 µm, or about 1.5–2.0 times body width. The nuclei of the dorsal and subventral glands mostly located posterior to the pharyngo-intestinal valve, in some specimens the dorsal gland is anterior to or level with the valve. All gland nuclei hardly seen and glands cover about only half of the body width ( Fig. 3 D & E and 6 F–H). Spermatheca rounded, filled with round sperm. Tail cylindrical to subcylindrical, ending to a coarsely striated terminus. Phasmids 19–29 µm posterior to the anus ( Fig. 3 : L–O and 6: K–M).

Male. Similar to females in general view. Body slightly curved ventrally. Lateral field with four or six incisures; outer band areolated. Lip region conical and higher than that of females ( Fig. 3 F & H and 6 C & D). Tail gradually tapering, ending to a conical terminus ( Fig. 3 J & K and 6 N).

Remark. Compared to the original description of P. nevadensis ( Talavera & Tobar, 1996) , the Iranian population has a slightly shorter stylet (18.8–21.8 vs 22–26 µm) and shorter pharynx (145–183 vs 178–254 µm). No other difference in morphologic or morphometric diagnostic characters was found. Our population also has affinities with P. ritteri and P. alkani , but differs in having narrow pharyngeal glands which do not fill the whole body cavity and in having different positions of the pharyngeal gland nuclei. During the present study, this population was recovered from the rhizosphere of walnut trees ( Juglans regia ) in Rashakan region, Urmia county, West Azerbaijan province, northwestern Iran (GPS coordinates: N 37° 19' 2" – E 45° 17'48").

Figures

FIGURE 3. Iranian population of Pratylenchoides cf. nevadensis, females (B–E & H–I & L–O) and males (A & F–G & J–K). A & B: Entire body; C: Anterior end; D–G: Pharyngeal region; H & I: Lateral field; J–O: Tail.

FIGURE 3. Iranian population of Pratylenchoides cf. nevadensis, females (B – E & H – I & L – O) and males (A & F – G & J – K). A & B: Entire body; C: Anterior end; D – G: Pharyngeal region; H & I: Lateral field; J – O: Tail.

FIGURE 6. Photomicrographs of Pratylenchoides cf. nevadensis females (A–B & E–M) and males (C–D & N). A & D: head and stylet. E: Pharynx. F–H: Pharyngeal glands and position of their nuclei. I: Lateral field. J: Spermatheca. K–N: tail. Scale bars = 10 µm. (a = anus; c = cardia; n = pharyngeal gland nuclei; s = spermatheca).