Diphtherophora caudata Ivanova, 1958

Ghaderi, Reza, Kashi, Leila, Karani, Hossein Mirbabaei & Karegar, Akbar, 2017, A new and four known species of Diphtherophora (Nematoda: Diphtherophoridae) from Iran, with a diagnostic compendium of its species, Zootaxa 4365 (3), pp. 311-330 : 315-317

Diphtherophora caudata Ivanova, 1958

( Figs 2 ; 6 A–C; 7 A, G; 8 A, B; 9 A, B)

Measurements. See Table 1 .

Female. Body habitus straight to slightly curved ventrally after heat relaxation. Cuticle moderately thick, about two-fifths of the body width; smooth, transparent, two-layered and separated from the body, except at secretoryexcretory pore, vulva and anus. Subcuticle layer smooth, about 1.5 µm thick. Head region continuous with the body contour. Outer labial papillae distinctly elevated. Amphid aperture ellipsoidal, about one-third of head width. Stoma a complex structure; spear guiding apparatus with weakly developed dorsal arch; anterior part of spear with paired dorsal pieces and a single ventral piece, these continue into a tubular extension terminating in asymmetrical basal knobs. Pharynx with cylindrical anterior part connected to a rounded, pyriform or elongate-cylindrical basal bulb. Some portions of pharynx could not be observed due to the presence of numerous granules in pharyngeal region. Nerve ring at mid-pharynx. Secretory-excretory pore located opposite the middle of the isthmus. Cardia not observed. Female reproductive system didelphic-amphidelphic, with reflexed ovaries. Sperm cells with rod-shaped or fusiform nuclei and usually numerous in the uteri. Vulva a transverse slit; vagina at right angles to the body axis, with moderately developed musculature. Rectum 13 µm or about two thirds of the anal body width. Tail elongateconoid, bent dorsally near the terminus. Sublateral caudal pores not observed near tail terminus.

Male. Body slightly curved ventrally. Ventromedian cervical papillae absent. Reproductive system monorchic, reaching mid-body, sperm cells with rod-shaped or fusiform nuclei in seminal vesicle. Two ventromedian precloacal supplements observed at about 7 and 20 µm anterior from cloacal aperture; the first between cloacal aperture and spicule head and the second about 5 µm anterior to spicule head. Spicules ventrally arcuate, without marked capitulum, width constant from anterior to blade, widening at mid-point and gradually tapering to the distal end, bifurcated tip. Spicular capsule moderately developed. Gubernaculum simple and slightly arcuate. Tail similar to that of female. Sublateral caudal pores seen near tail terminus.

Remarks. Ivanova (1958) distinguished D. caudata from D. communis by the somewhat shorter body and the more anteriorly located vulva. Andrássy (2009) found an intermediate population from Hungary and considered D. caudata as a junior synonym of D. communis . However, D. cadata has two ventromedian precloacal supplements (vs one in D. communis ) and has a different spicule shape (without vs with marked capitulum). D. caudata also comes close to D. ivanovae and D. tenera in regard to tail length and tail shape, respectively. Specimens of our Iranian populations differ from D. ivanovae in having larger body (646–723 vs 300–400 µm), cuticle appearance (smooth vs transversely striated), tail shape (bent dorsally vs bent ventrally) and head morphology (continuous vs off-set), and differs from D. tenera in higher c' (2.0–2.2 vs 1.2–1.5), slightly smaller spear (16–17 µm vs 17–23 µm) and absence of ventromedian cervical papillae in females (vs two papillae present).

In the present study, populations of this species were collected and identified from two localities in Iran: the first population with two females from the rhizosphere of walnut in Oshturan, Hamadan province; the other with one female and three males from a nursery (almond and apricot seedlings) in Marivan county, Kurdistan province; both in west of Iran.

Figures

FIGURE 2. Diphtherophora caudata Ivanova, 1958. Female (A–C, E–G) and male (D, H). A: Entire body; B: Anterior end; C: Part of reproductive system; D: Pharyngeal region; E, F: Pharyngeal basal bulb variation; G, H: Posterior end.

FIGURE 6. Anterior ends of Diphtherophora species from Iran. Females (A, B, D–I, K) and males (C, J, L). A–C: D. caudata; D: Diphtherophora sp.; E: D. obesa; F–H: D. perplexans; I, J: D. geraerti sp. n.; K, L: D. tenera. All scale-bars = 10 µm.