Ditylenchus equalis Heyns, 1964

Hashemi, Kobra & Karegar, Akbar, 2019, Description of Ditylenchus paraparvus n. sp. from Iran with an updated list of Ditylenchus Filipjev, 1936 (Nematoda: Anguinidae), Zootaxa 4651 (1), pp. 85-113 : 92

4. Ditylenchus equalis Heyns, 1964

8 females: L = 749 (602–861) µm; stylet = 7.4 (7–8) µm; pharynx = 118 (98–145) µm; tail = 73.5 (51–91) µm; a = 44.8 (35.6–57.5); b = 6.4 (5.4–8.2); c = 10.4 (9.1–12.3); c′ = 6.6 (4.2–8.5); V = 80.6 (78.9–82.6); V′ = 89.3 (88.1– 90.5); PUS/VBW = 1.2 (1.0–1.4; in one specimen = 2.1); PUS/V-A = 30.6 (20.9–58.4) %; V-A/T = 1.0 (0.8–1.2).

4 males: L = 537 (494–565) µm; stylet = 7.3 (7–8) µm; pharynx = 116 (104–134) µm; tail = 51.2 (50–53) µm; a = 44.1 (39.1–48.7); b = 4.6 (4.2–4.9); c = 10.5 (9.7–11.1); c′ = 5.1 (4.6–5.5); spicules = 14.9 (14–16) µm.

Diagnosis. D. equalis is characterised by four lateral field incisures, unstriated head, delicate, short stylet with rounded knobs, basal pharyngeal bulb pyriform to elongate and usually offset, sometimes with a slight overlap (up to 2 µm), posterior position of vulva, short post-vulval uterine sac, tail tip usually pointed and sometimes rounded, and short spicules.

D. equalis is similar to D. deiridus Thorne & Malek, 1968 , D. emus Khan, Chawla & Prasad, 1969 , D. exilis Brzeski, 1984 , D. filimus Anderson, 1983 , D. parvus and D. terricolus . It differs from D. deiridus by having PUS ( vs. PUS absent), and from D. emus and D. exilis by different shape of tail tip (usually pointed vs. rounded). It can be distinguished from D. filimus by shorter spicules (14–16 vs. 29 μm) and lower V index (78.9–82.6 vs. 81–85), from D. parvus and D. terricolus by greater V index (78.9–82.6 vs. 71–77) and lower PUS/VBW ratio (1.0–1.4 vs. 1.8–4.3 and 2.1–3.2, respectively).