Pratylenchoides leiocauda Sher, 1970

Ghaderi, Reza, Karegar, Akbar, Miraeiz, Esmaeil & Hashemi, Kobra, 2017, Comparative morphology of the anterior end of selected taxa of Merliniidae Siddiqi, 1971 (Nematoda: Tylenchoidea), with morphological characterisation of two species and taxonomic keys to several genera, Zootaxa 4300 (4), pp. 571-588 : 578-579

Pratylenchoides leiocauda Sher, 1970

( Figs 5 & 6 )

Measurements. See Table 2.

Female. Body almost straight with slight ventral curvature after fixation. Cuticle annuli about 1 µm wide at mid-body. Lateral field usually with six (rarely four) incisures near mid-body, the two inner ones obscure at the level of deirids and at the posterior end. Outer bands incompletely areolated on some parts of the body, typically on the tail. Labial region continuous with the body contour, anteriorly flattened, 5–6 µm high and 9–11 µm wide at base, with three or four distinct annuli. Cephalic framework well developed, with posterior margin extending over two annuli. Stylet robust, twice as long as cephalic region diameter at base, conus 8–10 µm and slightly shorter than half of the stylet (m = 45–48), basal knobs directed laterally or slightly sloping backward. Dorsal pharyngeal gland orifice 2–4 µm from stylet base. Median bulb oval with distinct valve apparatus, 63–69 µm from anterior end. Nerve ring situated slightly anterior to mid-isthmus, 76–85 µm from the anterior end. Hemizonid two annuli wide, two to three annuli anterior to secretory-excretory pore. Deirids present within the four lateral lines, two to five annuli anterior to secretory-excretory pore. Pharyngeal glands overlapping intestine dorsally, 2–4 times the corresponding body diameter. Pharyngo-intestinal valve pyriform, usually shifted ventrally. The dorsal pharyngeal gland nucleus and one of the subventral gland nuclei level with or slightly anterior to the pharyngo-intestinal valve; the second subventral gland nucleus posterior to the valve. Intestinal fasciculi indistinct. Vagina shorter than half of the corresponding body diameter. Spermathecae round, axial, with irregular rounded to spindle-shaped sperm. Tail cylindrical or sub-cylindrical, with rounded terminus, mostly smooth, or occasionally coarsely annulated. Tail with distinct hyaline region, but without refractive inner cuticular layer. Phasmids 15–26 µm posterior to anus, usually near middle of tail.

Male. Body almost straight after heat fixation. Cephalic region truncate-conoid, higher and narrower than that of female. Stylet slightly shorter and more slender than in female, with smaller basal knobs. Median bulb and pharyngeal glands weakly-developed, nuclei obscure. Caudal alae with crenate margins, arising at level of spicules and extending to tail terminus. Spicules slightly curved ventrad, gubernaculum simple. Tail tapers gradually to a conoid terminus.

Remarks. Our population fits with the original description of P. leiocauda ( Sher 1970) , except that the pharyngeal glands overlap a longer portion of the intestine (2–4 vs. 1–2 times the corresponding body diameter), tail is slightly longer (c = 12–17 vs. 17–22), having more annuli (21–26 vs. 16–21). The Iranian population also comes close to P. crenicauda , but has a longer overlap of the pharyngeal glands over the intestine and has a usually smooth tail terminus. Ghaderi & Karegar (2014b) mentioned that the prviously-reported population from Iran appears to be P. crenicauda ; that population has a short pharyngeal gland overlap of the intestine (less than half of corresponding body diameter), 27 tail annuli and a striated tail terminus. Therefore, the present study can be considered the first report of P. leiocauda from Iran. This population was collected from the rhizosphere of apple trees in Gorgan county (Golestan province), northern Iran .

range); measurements are in µm).

Character\Species Pratylenchoides leiocauda Telotylenchus paaloofi

Figures

FIGURE 5. Pratylenchoides leiocauda: Female (A – C & F – H) and male (D & E). A. Pharyngeal region; B. Pharyngeal glands; C & D. Anterior end; E – H. Tails. All Scale-bars = 10 µm.

FIGURE 6. Pratylenchoides leiocauda: Female (A – C, E, F – I, K – N) and male (D, E, J, O). A – D. Anterior end; E. Entire body; F – H. Pharyngeal region; J. Spicules and gubernaculum; K – O. Tails. Scale-bars: A – D, I – N = 10 µm; F – H, O = 20 µm; E = 50 µm.