Antarctenchus urmiensis, Amiri Bonab & Abolafia & Pedram, 2021

Amiri Bonab, Mohammad, Abolafia, Joaquín & Pedram, Majid, 2021, An interesting rare tylenchid species, Antarctenchus urmiensis n. sp. (Tylenchomorpha; Psilenchidae) from Urmia Lake islands, northwest Iran, with a discussion on the taxonomy of related genera, Journal of Nematology 53 (1), pp. 1-14 : 3

Antarctenchus urmiensis n. sp.

Figures 1-3 .

Measurements

See Table 1.

Female

Body ventrally curved, C shape after fixation, slender (mostly at neck region), gradually narrowing towards distal end. Cuticle finely annulated all over the body (from post cephalic plate to tail tip), the transverse striae sometimes not reaching the lateral fields. Cephalic region low, wide, with four annuli in SEM, its base ca. 3.4 times the height, or ca. 1.5 times wider than the width at apex. Lateral fields with four lines in the anterior and posterior body region, increasing to six at mid-body. Deirid at secretory-excretory pore (S-E pore) level, phasmids at about mid-tail. Stylet short, its conus shorter than the shaft, abut 37–46% of the total stylet, with three tear-drop like knobs. The stylet guiding apparatus complex, usually three rings were observed, forming two chambers at shaft region. Pharynx tylenchoid, procorpus slender, metacorpus small, oval, at 40.0–45.8% of the pharynx with weak valve, isthmus narrow, pharyngeal bulb small, with usually one visible nucleus. Cardia large. Intestine simple, rectum and anus functional. S-E pore position just anterior of pharyngeal bulb. Hemizonid distinct, just anterior to S-E pore. Nerve ring encircling isthmus. Reproductive system didelphic-amphidelphic, each branch composed of an ovary, with oocytes in a single row, oviduct tubular, spermatheca spherical, empty, crustaformeria quadricolumellate, uterus tubular, vagina weakly sclerotized, vulva a transverse slit, its lips slightly protruding, vulval flap and epyptigma absent. Tail conical, not elongatefiliform, usually slightly ventrally bent, with a sharp or blunt tip and a small indentation at dorsal side close to tip.

Male

Similar to female in general morphology except for reproductive system. Testis single, elongate, spermatocytes at single row behind germinal zone. Spicules tylenchoid, moderately sclerotized, slightly ventrally curved. Gubernaculum well sclerotized, crescent shaped. Bursa small, cloacal Tail similar to that of female.

Figures

Figure 1: Line drawings of ANtarCteNCHUS UrmieNSiS n. sp. (A-C, E-I: Female; D&J: Male) (A) Pharynx; (B) Anterior genital tract; (C&E) Anterior body end; (D) Male reproductive system; (F) Vulval region; (G&H) Female tail (phasmids are shown at two foci); (I) Bursa; (J) Male tail, spicule, and bursa.

Figure 2: Light micrographs of ANtarCteNCHUS UrmieNSiS n. sp. (A,B,E,F,G,H,I,J,M,P,Q: Female; C,D,K,L,N,O,R: Male) (A-D) Anterior body end; (E) Anterior body region; (F) Pharyngeal median bulb; (G) Part of female reproductive system; (H) Distal end of ovary; (I) Pharyngeal bulb; (J) Lateral lines; (K) Male tail; (L) Phasmid; (M) Female tail; (N) Bursa; (O&P) Entire body; (Q) Vulval region; (R) Spicule and gubernaculum. (Scale bars: A-N, Q&R = 10 μm; O&P = 50 μm).

Figure 3: Scanning electron microscopic (SEM) images of ANtarCteNCHUS UrmieNSiS n. sp. (Female) (A-C) Anterior end in ventral, sublateral and frontal views, respectively (arrows pointing the amphidial openings); (D) Deirid (withe arrow) and excretory pore in lateral view (black arrow); (E) Secretoryexcretory pore (arrow); (F) Lateral field; (G&H) Vulva in lateral and ventral views, respectively; (I) Posterior end in lateral view (arrow pointing the anus);(J) Anus (arrow) in lateral view; (K) Tail tip.