Parasitorhabditis obtusa ( Fuchs, 1915 ) Chitwood & Chitwood, 1950

Valizadeh, Ahmad, Goldasteh, Shila, Rafiei-Karahroodi, Zahra & Pedram, Majid, 2017, First record of the genus Parasitorhabditis Fuchs, 1937 (Rhabditida, Nematoda) from Iran with notes on morphological and molecular characters of the Iranian population of P. obtusa (Fuchs, 1915) Chitwood & Chitwood, 1950, Zootaxa 4353 (3), pp. 591-600 : 592-597

Iranian population of Parasitorhabditis obtusa ( Fuchs, 1915) Chitwood & Chitwood, 1950

( Figs. 1 ; 2)

Measurements. See Table 1.

… continued on the next page Female. Straight to ventrally accurate after heat killing. Cuticle smooth under LM, lacking discernible lateral fields in cross section. Cephalic region continuous with body contour, anteriorly flattened, cephalic framework weak, lips not protruding. Amphidial apertures hardly visible. Stoma well developed, promesostom cylindrical, devoid of teeth, with slight bifurcation at base of the cheilostom with straight parallel walls. Esophastome short. Pharynx rhabditoid, with muscular procorpus, slightly swollen at the junction with isthmus, the latter elongate. Basal bulb pyriform, set off, its valve well-developed. Cardia distinct, intestine simple and anus functional. Excretory pore at the level with the anterior part of pharyngeal bulb or at the middle of isthmus. Nerve ring surrounding middle of the isthmus, anterior to excretory pore, 121-150 µm from anterior end. Reproductive system monodelphic-prodelphic, occupying 41-64% of the total body length and composed of a reflexed ovary with oocytes arranged usually in two rows. Mature eggs at distal end of genital tract measuring ca. 24 × 41 µm. Vagina anteriorly directed, about one third corresponding body diameter long. Vulva a transverse slit without flap or epiptygma. Tail short, conoid, with blunt or narrow tip, with or without a spike or a projection.

Male. Common, as frequent as females. General morphology similar to that of female (slightly shorter), except for characters-states associated with sexual differences. Testis single, the genital branch occupies 47-66% of total body length. Spermatocytes arranged in multiple rows. Spicules separated, with straight blade and very short curved head. Gubernaculum simple, rod-shape. Bursa well developed, peloderan, with smooth margin. Genital papillae generally eight or nine pairs in number. Tail conoid with finely rounded tip.

Locality and habitat. Recovered from galleries in pine tree barks in different regions of the city of Tehran ( Table 2). The described population belongs to the population recovered from the bark of a dead pine trees in Lavizan region. The live females and males were also obtained from the inside of dissected bodies of Orthotomicus erosus individuals collected in association with dead pine trees.

Figures

FIGURE 1. Line drawings of Iranian population of Parasitorhabditis obtusa. A: Male entire body; B: Female pharyngeal region; C: Female genital tract; D-G: Female tail variation; H: Male tail in ventral view; I: Male tail in lateral view; J: Female entire body.