Diphtherophora tenera Ivanova, 1980

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 : 321-323

Diphtherophora tenera Ivanova, 1980

( Figs 5 ; 6 K, L ; 7 E, F, J ; 8 L ; 9 I–K)

Measurements. See Table 3 .

Female. Body habitus slightly ventrally directed after fixation. Cuticle relatively thick, two-fifths to one-half of the body width; smooth, transparent, two-layered and loosely separated from the body along most of the body length. Subcuticle layer about 1.5 µm thick. Head region continuous with the rest of body. Amphid aperture ellipsoidal and about one-third of head width at base. Two ventromedian cervical papillae were observed at 22–28 µm (at the spear base) and 66–75 µm from anterior end (or 15 µm anterior to the secretory-excretory pore). Lateral pores not observed at the spear base. Spear guiding apparatus arched, with moderately developed sides. Spear and pharynx typical for the genus; posterior part of pharynx pyriform. Nerve ring at mid-pharynx region. Secretoryexcretory pore located near the posterior end of isthmus. Cardia not observed. Female reproductive system with two reflexed ovaries. Sperm spindle-shaped and distributed along the uteri. Vagina directed somewhat anteriorly, with relatively well-developed musculature. Rectum 12–16 µm or 40–45 % of the anal body width. Tail conoid, slightly longer than the anal body width; bent dorsally near terminus.

Male. Body slightly curved ventrally. Two ventromedian cervical papillae 20–25 and 63–70 µm from the anterior end: level with spear base and about 15 µm anterior to secretory-excretory pore, respectively. Reproductive system monorchic and outstretched, extending to near mid-body. Three ventromedian supplements, two of them situated 7–10 and 15–22 µm anterior to cloacal aperture and the third observed 8–10 µm posterior to cloaca. Spicules arcuate, without marked capitulum, proximal part with parallel sides equally wide, suddenly narrowing about mid-spicule but still parallel with equally wide, then wider again, and gradually tapering to the bifurcate distal end. Bristle-like structures not observed in the middle of spicule. Gubernaculum simple and relatively long. Tail with dorsally bent terminus, as in female. A pair of sublateral caudal pores observed near tail terminus.

Remarks. Diphtherophora tenera differs from all Diphtherophora species in having two ventromedian cervical papillae in females. These structures are not common in females of Diphtherophoroidea Micoletzky, 1922; in the genus Diphtherophora , only D. tenera (two papillae) and D. bulgarica (one papilla) have ventromedian cervical papillae. In the original description of D. tenera ( Ivanova 1980) , presence of ventromedian neck papillae in females was not mentioned in the text, but the drawing of the female has two separate papillae between the spear base and secretory-excretory pore. Morphometric data of our population fit well with those of the paratypes, but the spear is slightly smaller in males (17–19 vs 18–23 µm) from Iran. Furthermore, D. tenera differs from all species, except D. communis , in having a dorsally directed tail terminus; however, tail is longer in the latter species (c' = 1.2–1.5 vs 2.0–2.5).

This species was described from the rhizosphere of fruit trees in Tadzhikistan ( Ivanova 1980). In the present study, a population of the species was collected and identified for the first time in Iran from around forest trees in Kabudval forest, Ali Abad-e-Katul, Gorgan province, northern Iran.

Figures

FIGURE 5. Diphtherophora tenera Ivanova, 1980. Female (A–C, E, F) and male (D, G). A: Entire body; B, D: Pharyngeal region; C: Anterior end; E: Part of reproductive system; F, G: 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.

FIGURE 7. Pharyngeal regions (A–F) and spermatozoa (G–J) of Diphtherophora species from Iran. Females (A–E) and males (F–J). A, G: D. caudata; B, H: Diphtherophora sp.; C: D. obesa; D, I: D. geraerti sp. n.; E, F, J: D. tenera. All scale-bars = 10 µm. (e: excretory pore; v: ventromedian cervical papillae).

FIGURE 8. Female tails of Diphtherophora species from Iran. A, B: D. caudata; C, D: Diphtherophora sp.; E, F: D. obesa; G, H: D. geraerti sp. n.; I–K: D. perplexans; L: D. tenera. All scale-bars = 10 µm.

FIGURE 9. Male posterior ends of Diphtherophora species from Iran. A, B: D. caudata; C, D: Diphtherophora sp.; E, F: D. obesa; G, H: D. geraerti sp. n.; I–K: D. tenera. All scale-bars = 10 µm. (s = preanal supplements).