Nothotylenchus geraerti Kheiri 1971

1. Nothotylenchus geraerti Kheiri, 1971 48 females: L = 742 ± 122 (506–1172) µm; stylet = 7.3 ± 0.3 (6.5–8) µm; pharynx = 127 ± 17 (96.5–167) µm; tail = 59.6 ± 8.1 (43.5–77) µm; a = 37.6 ± 4.9 (28.7–50.0); b = 5.8 ± 0.6 (4.6–7.6); c = 12.3 ± 1.4 (9.3–15.6); c′ = 4.9 ± 0.6 (3.7–6.1); V = 81.0 ± 2.3 (74.8–84.6); V′ = 88.3 ± 2.3 (82.0–95.8); PUS/VBW = 1.8 ± 0.4 (1.1–3.0); PUS/V-A = 42.9 ± 11.7 (14.8–77.0) %; V-A/T = 1.3 ± 0.2 (0.9–2.2). 10 males: L = 609 ± 75 (493–738) µm; stylet = 7.2 ± 0.2 (7–7.5) µm; pharynx = 122 ± 17 (98–154) µm; tail = 57.1 ± 7.5 (46.5–68.5) µm; a = 38.5 ± 2.6 (34.7–42.6); b = 4.9 ± 0.2 (4.6–5.3); c = 10.8 ± 1.6 (8.2–13.3); c′ = 5.0 ± 0.8 (4.1–6.3); spicules = 16.9 ± 1.1 (15.5–18.5) µm. Diagnosis and relationships. Nothotylenchus geraerti is characterised by its medium-sized body, six lateral field incisures, delicate stylet with posteriorly-sloping knobs, pyriform or slightly elongate and offset or slightly overlapping basal pharyngeal bulb, posterior vulva position, medium-sized spicules, and variable tail terminus shape (rounded to pointed). The studied populations of N. geraerti are similar to N. affinis, N. hexaglyphus, N. medians, N. taylori and N. tuberosus. The species differs from N. hexaglyphus by its more developed stylet and knobs, greater PUS/VBW ratio (1.1–3.0 vs. 0.5–1.1) and shorter spicules (15.5–18.5 vs. 19–22 μm). The four other species are very similar to N. geraerti, and, as their differentiation is so difficult, we think that these four species may all be synonymous. However, according to other published studies (Kheiri 1971, Husain & Khan 1974, Brzeski 1991, Zeidan & Geraert 1991), N. geraerti differs from N. affinis by its shorter stylet (6.5–8 vs. 8–9 μm), higher head, and greater PUS/VBW average (˃1.5 vs. ˂1.5), from N. medians by higher head, posteriorly slopping knobs (vs. rounded) and less-thick tail (vs. thick), from N. taylori by its relatively shorter spicules (maximum length ˂ 19 vs. ˃ 19 μm), and from N. tuberosus by shorter uterus length/VBW ratio (˂ 3 vs. 3–4) and basal bulb shape (mostly pyriform and offset vs. slightly overlapping). All of the features used to differentiate these four species display inter-population variation, making further studies on their type specimens necessary.
Published as part of Hashemi, Kobra & Karegar, Akbar, 2020, New and known species of Nothotylenchus Thorne, 1941 (Nematoda: Anguinidae) from Iran with an updated list of species, pp. 482-500 in Zootaxa 4729 (4) on page 491, DOI: 10.11646/zootaxa.4729.4.2, http://zenodo.org/record/3752014
{"references":["Kheiri, A. (1971) Two new species of Nothotylenchus Thorne, 1941 from Iran and a redescription of N. affinis Thorne, 1941 (Nematoda, Neotylenchidae) with a key to the species of the genus. Nematologica, 16 (1970), 591 - 600. https: // doi. org / 10.1163 / 187529270 X 00810","Husain, S. I. & Khan, A. M. (1974) Three new species of neotylenchid nematodes from north India. Indian Journal of Nematology, 4, 81 - 87.","Brzeski, M. W. (1991) Review of the genus Ditylenchus Filipjev, 1936 (Nematoda: Anguinidae). Revue de Nematologie, 14, 9 - 59.","Zeidan, A. B. & Geraert, E. (1991) The Genus Ditylenchus Filipjev, 1936 in Sudan (Nematoda: Tylenchida). Afro-Asian Journal of Nematology, 1, 5 - 14."]}