Mylonchulus cf. hawaiiensis ( Cassidy, 1931 ) Goodey, 1951

Shokoohi, Ebrahim, Mehrabi-Nasab, Abdolrahman, Mirzaei, Mahdieh & Peneva, Vlada, 2013, Study of mononchids from Iran, with description of Mylonchulus kermaniensis sp. n. (Nematoda: Mononchida), Zootaxa 3599 (6), pp. 519-534 : 520-524

Mylonchulus cf. hawaiiensis ( Cassidy, 1931) Goodey, 1951

( Figs. 1 (A–E) & 2)

Material examined. 10 females, in good state of preservation.

Measurements. See Table 2.

Description. Female: Body almost cylindrical, ventrally curved after fixation. Cuticle smooth under LM. Head region continuous with neck, having six lips bearing 6 + 4 papillae. Amphid openings oval, aperture 3–5 µm wide, located 9–12 µm from anterior end. Six transverse rows of rasp-like denticles on subventral walls located posterior to the dorsal tooth. Buccal cavity large, elongate goblet -shaped, about 1.9–2.1 times as long as wide, with thick, heavily cuticularised vertical walls, 1.4–2 µm diameter. Dorsal wall bearing a sharp, slightly pointed, 6–8 µm long and 2.5–3 µm wide dorsal tooth, directed forward, located in the anterior half of buccal cavity at 56–62% from its base; each two foramina present at the base of buccal cavity lying close to each other, 5–6 µm long. Nerve ring located at 32–35% of neck length, excretory pore at 34–37%, respectively. Cardia conoid, surrounded by intestinal tissue. Reproductive system amphidelphic. Ovaries more or less straight, reflexed and with a single row of oocytes. Oviduct 60–69 µm long, 1.6–1.9 times the corresponding body diameter. Uterus short, 12–17 µm long, 0.3–0.5 the corresponding body diameter. Vagina with parallel wall, less than half of the corresponding body diameter, pars refringens vaginae with two boot-shaped sclerotisations. Vulva not protruding and located near mid body. Advulval papillae not observed. Egg length 1.9–2.3 times the corresponding body diameter. Rectum 0.7–0.8 times the anal body diameter. Tail arcuate, bent ventrad. Caudal glands in tandem, spinneret opening terminal.

Male. Not found.

Locality. The material has been found with Phoenix dactylifera L. in Jiroft (province of Kerman, Iran), southeastern Iran (N: 28º 36’ 20.17”; E: 057º 43’ 08.87”).

Remarks. Mulvey (1961) considered M. hawaiiensis to be a synonym of M. incurvus Cobb, 1917 . Andrássy (1958) showed that this species is completely different from M. incurvus . Comparison of the two mentioned species showed that M. hawaiiensis and M. incurvus differ in buccal cavity size, body length and tail length and shape. According to the key by Ahmad and Jairajpuri (2010), M. hawaiiensis resembles M. brassicus Soni & Nama, 1980 , however it has more posterior vulva (55–70 vs 54–57) and shorter tail in males (c=35–44 vs c=23). In addition, male of M. hawaiiensis posses 10–12 supplements (vs 6 supplements). Further, these specimens are close to M. lacustris (Cobb in Cobb, 1915) Cobb, 1917 in the key by Andrássy (1992). Data on morphology of populations identified as M. lacustris vary greatly ( Jensen & Mulvey, 1968; Jairajpuri, 1970; Andrássy, 1992; De Bruin & Heyns, 1992, Loof, 1999, etc) and it seems that not all of them are conspecific. Compared with the original description and material reported by Jensen & Mulvey, (1968), De Bruin & Heyns (1992) and Loof (1999), Iranian females differ in body length (0.9–1.6 vs 1.5–2.5 mm), buccal capsule size (24– 30 x 11–17 vs 30– 39 x 17–21 µm), tail shape (ventrally bent vs cylindrical) and length (38–49 vs 66–115 µm, c’=1.4–2.0 vs c’=2.0–3.0), number of rows of rasp-like denticles (6 vs 7). Material studied differ also from populations originating from India ( Jairajpuri, 1970; Andrássy, 1992) in body length (0.92–1.13 vs 1.1–1.6 and 1.16–1.24 mm, respectively), number of rows of rasp-like denticles (6 vs 7 and 5–6, respectively), buccal capsule size (24–30 vs 23–24 µm in Bombay population), nerve ring position (79–97 vs 110–125 µm from anterior end), and tail shape (more vs; ventrally slightly arcuate).

The populations reported as M. hawaiiensis from several localities across its wide range (Asia, Africa, Central and South America) showed high intrapopulation variability. Iranian specimens compared to those studied from India, Costa Rica and Nigeria ( Jairajpuri, 1970; Mulvey & Jensen, 1967; Zullini et al., 2002) have a longer tail (38–49 µm vs 23–42 µm). Further, the buccal capsule of the studied population is longer compared to that of material from Nigeria and India (24–31 vs 20–23 and 22–25 μm, respectively) ( Mulvey & Jensen, 1967; Jairajpuri, 1970). Finally, the Iranian specimens have shorter necks compared with materials from Argentina and Costa Rica (224–303 vs 279–345 and 352 μm) ( Chaves, 1990; Zullini et al., 2002). Morphological comparison with M. hawaiiensis populations reported from Japan ( Olia et al., 2009) is not possible because the author did not present any data on the morphology of the five populations studied.

This species is reported for the first time from Iran.

Figures

FIGURE 1. Mylonchulus cf. hawaiiensis (Cassidy, 1931) Goodey, 1951. (A-E) A: Neck. B: Buccal cavity. C: Female reproductive system. D: Entire female. E: Female posterior end; Mononchus truncatus Bastian, 1865. (F – I) F: Buccal cavity. G: Entire female. H: Female reproductive system. I: Female posterior end.