Diphtherophora geraerti, Ghaderi & Kashi & Karani & Karegar, 2017

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 : 312-315

Diphtherophora geraerti sp. n.

( Figs 1 ; 6 I, J ; 7 D, I ; 8 G, H ; 9 G, H )

Measurements. See Table 1 .

Female. Body habitus slightly curved ventrally after fixation. Cuticle smooth and relatively thick, about twofifths of the body width. Subcuticle layer smooth, about 2 µm thick. Head region continuous with the body contour. Outer labial papillae obscure. Amphid aperture oval in shape, as wide as one-third to half of the head width at base. Spear typical of the genus, tip sclerotised. Stylet guiding apparatus arched, weakly sclerotised. Pharynx typical of the genus and composed of two parts, the anterior slender part expanding gradually to form a rounded or sometimes slightly pyriform terminal bulb. Nerve ring located at mid-pharynx region or posterior to it. Secretoryexcretory pore opposite posterior end of isthmus or beginning of pharyngeal bulb. Cardia not seen under light microscope.

Reproductive system didelphic, amphidelphic, with branches equally developed, ovaries reflexed with germinal zones directed toward vagina, spermatheca not present at the junction of oviduct and uterus. Sperm cells with rod-shaped or fusiform nuclei and usually numerous throughout the uteri. Vulva a transverse slit in ventral view. Vagina orthogonal to the body axis, with well-developed musculature. Rectum 9–13 µm or 40–50 % of the anal body width. Tail slightly convex-conoid, with bluntly rounded to hemispherical terminus. The tail terminus lacks lateral caudal pores.

Male. Similar to female in general. Body habitus slightly curved ventrally. Two cervical ventromedian papillae, respectively 22–25 and 52–60 µm from the anterior end, or alternatively, the first papilla situated 4–5 µm posterior to the stylet base and the second 18–28 µm anterior to secretory-excretory pore. No lateral body pore seen in anterior region of body. Reproductive system monorchic, extending to near mid-body and containing numerous rod-shaped or fusiform spermatozoa. Two ventromedian precloacal supplements were observed, the first in the region of the spicules and the second further anterior: 11–13 and 75–80 µm anterior to the cloacal aperture, respectively. Spicules slender and nearly straight to slightly arcuate. Spicular capsule relatively weak. Gubernaculum ventrally arcuate at anterior tip. Two sublateral pores were observed near the tail terminus. Tail similar to females, with bluntly rounded terminus.

Type material. Sixteen specimens (10 ♀ and 6 ♂) deposited in the collection of the Department of Plant Protection, School of Agriculture, Shiraz University, Shiraz, Iran.

Type host and locality. This species was collected from the rhizosphere of apple trees in Urmia county, West Azarbaijan province, northwestern Iran.

Etymology. The species is named in honor of Dr. Etienne Geraert, the well-known authority on the taxonomy of nematodes.

Diagnosis and relationships. The new species is characterised by females with head continuous with the body contour, spear 12–13 µm in length, rod-shaped spermatozoa and conical tail with bluntly rounded to hemispherical terminus, and males with two ventromedian neck papillae 22–25 and 52–60 µm from the anterior end, and two

ventromedian supplements at 11–13 and 75–80 µm anterior from cloacal aperture, respectively. The new species comes close to D. siddiqii Eroshenko & Tepljakov, 1977 , D. brevicollis , D. lata Thorne, 1974 , D. obesa Thorne, 1939 , D. citri Husain, Khan & sʼJacob, 1965 , D. vasilevi Nedelchev & Choleva, 1989 and D. vitoshae Nedelchev & sʼJacob, 1993 . Females of D. geraerti sp. n. have a different tail terminus shape (bluntly rounded to hemispherical vs finely rounded), less sclerotised vaginal ring, higher b value (4.4–5.4 vs 3.7–4.2) and more anterior vulva position (57–59 vs 61–65) than D. siddiqii . The new species differs from D. brevicollis in having a smaller body (459–584 µm vs 660 µm), lower c value (22–27 vs 33), slightly more posterior vulva (V = 57–59 vs 54), in spicule shape (slender with marked capitulum vs stout without marked capitulum), and in having two ventromedian precloacal supplements (vs one) and two cervical ventromedian papillae (vs absent) in males. It differs from D. lata in having a shorter spear (11–14 vs 16 µm) and spicules (15–18 vs 25 µm), presence of two cervical ventromedian papillae (vs absent), and in the position of the second ventromedian precloacal supplements (75–80 vs about 40 µm anterior to the cloacal aperture). From D. obesa , it differs in its shorter spear (11–14 vs 14– 18 µm), tail shape (slightly convex-conoid with a rounded terminus vs conoid with subdigitate terminus) and shape of spermatozoa (sperm cell with rod-shaped or fusiform nucleus vs rounded to oval shape). D. citri differs from the new species by having a longer stylet (15–19 vs 11–14 µm), narrower body (a = 21–28 vs 12–17) and absence of males (vs present). Two other species, D. vasilevi and D. vitoshae , have slightly longer spears (average 15.4 and 14.5 µm, respectively) and larger bodies (both average 700 µm); furthermore, D. vasilevi has three preanal supplements in males, while D. vitoshae has a different spicule shape.

Figures

FIGURE 1. Diphtherophora geraerti sp. n. Female (A, B, D, E) and male (C, F). A: Entire body; B: Anterior end; C: Pharyngeal region; D: Part of reproductive system; E, F: 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).

Tables

TABLE 1. Morphometric characters of Diphtherophora geraerti sp. n. and Iranian population of D. caudata (measurements are in µm).

Character\Source		D. geraerti sp. n.				D. caudata
	Holotype	Females-paratypes	CV	Males	CV	Females	Males
n	-	10		6		3	3
L	508	518 ± 40.9 (459-584)	7.9	451 ± 34 (406-488)	7.6	690 ± 39.5 (646-723)	673 ± 14.1 (658-686)
a	15.4	14.1 ± 1.6 (12.2-16.8)	11.1	14.0 ± 1.3 (11.7-15.4)	9.4	23.6 ± 1.3 (22.6-25.1)	24.9 ± 0.6 (24.4-25.6)
b	4.5	5.0 ± 0.3 (4.4-5.4)	6.5	4.4 ± 0.2 (4.1-4.7)	4.6	4.4 ± 0.5 (3.9-4.9)	4.8 ± 0.3 (4.6-5.2)
c	26.1	24.7 ± 1.5 (22.0-26.5)	6.2	17.5 ± 2.0 (15.4-20.5)	11.5	15.4 ± 0.5 (15.2-16.0)	13.5 ± 1.3 (12.0-14.5)
c'	1.0	1.0 ± 0.1 (0.9-1.1)	8.8	1.2 ± 0.1 (1.1-1.4)	12.2	2.1 ± 0.1 (2.0-2.2)	2.1 ± 0.2 (1.9-2.3)
V	59.3	57.9 ± 0.8 (57.0-59.3)	1.4	_	_	54.7 ± 0.7 (54.2-55.5)	_
Stylet	12.7	12.3 ± 0.4 (12-13)	3.4	11.9 ± 0.9 (11-14)	7.4	16.3 ± 0.8 (16-17)	15.2 ± 0.9 (14-16)
Pharynx	112	105 ± 6.4 (90-112)	6.1	102 ± 5 (96-108)	4.8	157 ± 25.6 (132-184)	141 ± 10.1 (130-150)
S.E. pore	80.0	78.7 ± 4.3 (72-85)	5.5	78.8 ± 1.5 (78-81)	2.0	80.8 ± 5.9 (74-86)	84.6 ± 6.2 (79-92)
Nerve ring	62.0	60.2 ± 3.1 (55-65)	5.2	64.0 ± 1.9 (62-66)	3.0	76.6 ± 4.8 (71-81)	74.3 ± 5.6 (68-78)
Head-vulva	301	297 ± 19.0 (265-335)	6.4	_	_	377 ± 25.7 (350-401)	_
Head-anus	489	497 ± 39.2 (440-560)	7.9	425 ± 34 (380-463)	8.0	645 ± 38.0 (603-678)	623 ± 18.1 (603-639)
Vulva-anus	188	199 ± 23.3 (175-249)	11.7	_	_	268 ± 12.5 (253-277)	_
Tail length	19.4	21.1 ± 2.1 (19-25)	10.1	25.9 ± 2.5 (23-30)	9.7	44.7 ± 1.9 (43-46)	50.3 ± 4.1 (47-55)
Body width (BW)	33.0	37.2 ± 6.1 (30-48)	16.5	32.5 ± 4.3 (27-39)	13.1	29.2 ± 1.6 (28-31)	27.0 ± 0.3 (27-27)
VBW	31.3	34.6 ± 6.2 (29-46)	17.9	_	_	27.6 ± 1.7 (26-30)	_
ABW	18.5	21.0 ± 1.9 (19-23)	8.8	21.6 ± 2.4 (18-25)	11.2	21.4 ± 1.0 (20-22)	23.6 ± 2.0 (22-25)
Spicules	-	_	_	17.0 ± 1.5 (15-19)	8.7	_	17.1 ± 0.9 (16-18)
Gubernaculum	-	_	_	5.9 ± 0.9 (5-7)	14.8	_	5.3 ± 0.6 (5-6)