Tylolaimophorus minor (Thorne, 1939) Goodey, 1963

Ghaderi, Reza, Asghari, Ramezan & Eskandari, Ali, 2020, Systematics of the genus Tylolaimophorus de Man, 1880 (Nematoda Diphtherophoridae), with description of T. minor (Thorne, 1939) Goodey, 1963 from Iran, Zootaxa 4755 (2), pp. 322-340 : 336-337

Description of the Iranian populations of T. minor

( Figures 1 , 2 ; Table 2 )

Female. Body slightly curved ventrally to C-shaped. Cuticle about 1 µm thick; cuticle and subcuticle layer bearing fine transverse striations. Lateral pores and ventromedian neck papillae not observed. Lip region continuous with the body contour, 8-11 µm in width. Papillae on lip region obscure. Amphidial opening about 4-5 µm wide or one-third of lip region width. Spear typical for the genus, bearing symmetrical basal knobs. Pharynx with fusiform median swelling and short pyriform basal bulb abutting the intestine. Pharyngeal basal bulb with three gland nuclei, the dorsal one larger than the two subventral ones. Three-celled cardia located between pharynx and intestine. Nerve ring surrounding isthmus and located 43-57 µm from anterior end. Excretory pore level with the beginning of pharyngeal basal bulb. Female reproductive system didelphic-amphidelphic, with reflexed ovaries. Spermathecae absent and uterus devoid of sperm cells. Vulva a circular slit in ventral view. Vagina extending 6-8 µm into body, with well-developed sclerotization. Rectum with thick walls. Post-anal intestinal sac extending into tail as far as 0.5-1.0 anal body diameter. Tail dorsally convex-conoid, ending in a bluntly rounded terminus. Caudal pores not observed.

Male. Not found.

Remarks. The two Iranian populations were recovered as follows: 1) from the rhizosphere of alder trees of Poonel Forest in Rezvan-Shahr, Gilan province, northern Iran; and 2) from the rhizosphere of hawthorn trees in Gisum Park, Talesh, Gilan province, northern Iran. This is the first report of any species of the genus Tylolaimophorus from Iran. Considering morphological and morphometric characteristics ( Table 2 ), the Iranian populations fit well with other populations of T. minor worldwide ( Thorne 1939, Eroshenko & Tepljakov 1977, Brzeski 1994); however, the stylet is longer in Russian populations ( Eroshenko & Tepljakov 1977) than in other populations from the USA, Poland and Iran.

Figures

FIG. 1. Tylolaimophorus minor from Iran. Female (A-G). A: Entire body; B: Anterior end and pharyngeal region; C: Cephalic region and spear; D: Posterior end; E-G: Vulval region.

FIG. 2. Tylolaimophorus minor from Iran. Female (A-H). A: Entire body; B: Anterior end and pharyngeal region; C: Cephalic region and spear; D, E: Vulva and part of reproductive system; F-H: Posterior end. (Scale-bars: A = 200 µm; B, D, F-H = 20 µm; C, E = 10 µm).

Tables

TABLE 2. Morphometric data of the females of Tylolaimophorus minor from Iran and its comparison with other populations (measurements are in µm).

		Present study		Poland	Russia	USA
Characters		Rezvan Shahr	Talesh	Brezeski, 1994	Eroshenko & Tepljakov, 1977	Thorne, 1939
n		9	2	22	19	-
L		458 ± 55 (378-545)	483, 400	482 (423-576)	340-600	600
a		17.0 ± 1.6 (14.6-19.1)	22, 20	15 (13-17)	10-23	17
b		4.8 ± 0.5 (4.1-5.6)	5, 4	5.2 (4.6-5.9)	3.7-6.1	6.3
c		18.2 ± 1.0 (16.1-19.1)	18.4, 16	19 (17-23)	12-18	20
c’		1.4 ± 0.1 (1.2-1.6)	1.4, 1.7	1.2 (0.9-1.4)	-	-
V		53.7 ± 3.0 (48.1-58.2)	53.4, 55	55 (52-57)	-	50
Spear		11.7 ± 0.4 (11.0-12.0)	12, 11.5	10-12	12-15	-
Pharynx		95.9 ± 5.5 (87.0-103.0)	96, 100	93 (84-103)	53-64	-
Anterior end to nerve ring		48.2 ± 4.1 (43.0-57.0)	56, 50	-	-	-
Anterior end cretory pore	to ex-	65.4 ± 3.9 (59.0-70.0)	67, 65	-	-	-
Cardia body width		24.4 ± 1.6 (22.0-26.5)	23.5, 20	-	-	-
Head-Vulva		245 ± 24 (220-281)	258, 220	-	-	-
Body Width(BW)		26.9 ± 2.5 (24.0-31.5)	22, 20	-	-	-
Anal Bady Width		18.7 ± 1.5 (17.0-21.0)	18, 15	-	-	-
Vulva - Anus		188 ± 34 (134-255)	199, 155	-	-	-
Tail		25.2 ± 2.4 (22.0-28.5)	26, 25	26 (22-31)	-	-
PUS rectal		13.6 ± 4.5 (8.0-21.0)	30, 7	-	-	-