Tylolaimophorus cylindricus ( Cobb, 1920 ) 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 : 329

Tylolaimophorus cylindricus ( Cobb, 1920) Goodey, 1963

After Cobb (1920)

After Thorne (1939)

After J. B. Goodey (1963)

After Thorne (1974) MEASUREMENTS

? paratype females: L = 1.2 mm; a = 30; b = 7.7; body width = 40 µm; spear = (18) µm; pharynx = 155 µm; tail = 30 µm; c = 40; c’ = 0.8; V = 54.

? paratype males: L = 1.0 mm; a = 25; b = (6.7); body width = 40 µm; spear =? µm; pharynx = 150 µm; tail = 30 µm; c = 34; c’ = 0.9; spicules = (40) µm; gubernaculum =? µm.

? females: L = 1.6-2.1 mm; a = 30; b = 8.0-12.0; c = 30-40; V = 53.

? males: L = 1.5-2.0 mm; a = 32; b = 11; c = 30-38.

? females: L = 1.6 mm; a = 30; b = 8-12; c = 30-40; V = 53.

? males: L = 1.5 mm; a = 32; b = 11; c = 30-38.

6 females: L = 1.4 mm; a = 30; b = 8.5; c = 30; V = 54.

DESCRIPTION

Female. Body arcuate, tapering to a very narrow, conoid lip region. Body tissues very dense, completely obscuring details in some specimens. Much of this density is due to hundreds of granular bodies, variable in size and form, which are distributed throughout the body. Cuticle marked by excessively fine transverse striae. Subcuticle with longitudinal striae which give rise to minute punctuations where they cross the transverse striae. Lip region continuous with the neck contour or slightly offset; six minute papillae around the oral opening. Outer circlet of ten papillae on low, conical elevations. Amphid apertures one third as wide as the head, the amphids extending deep into the tissues. Sensillae opposite spear base. A complicated sclerotized, tubular structure surrounds the vestibule, serving as the spear guide. Spear in two basally knobbed sections; the dorsal sector of arch-like construction, the ventral one a simple rod with the anterior end joined to the ventral side of the pharynx. Pharynx a slender tube ending to the pyriform to the elongate-conoid basal bulb which contains upwards of fifty granular bodies, apparently similar to those in the body cavity. Intestinal walls dense and generally undefinable. Vulva a transverse slit. Vagina extending about one third to halfway across the body to join the elongate, pouch-like uterine sac which extends approximately four body widths anteriad and posteriad from the vagina. Ovaries reflexed about halfway to the vulva. Intestine extending a short distance into the caudal cavity. Rectum length one fifth the anal body diameter. Tail with a bluntly rounded terminus.

Male. Testis single, outstretched (T = 65). Spicules almost semicircular with conspicuous musculature. Gubernaculum a thin trough in which the spicules glide. An obscure ventromedian elevation occuring just anterior to the spicules, the only trace of supplementary organs seen.

DIAGNOSIS AND RELATIONSHIPS

Tylolaimophorus cylindricus can be distinguished from the most closely related species, T. bulgaricus , mainly by having a smaller number of ventromedian precloacal supplements in males (one vs five). It can be differentiated from T. typicus and T. kasbegi by having a larger body size (greater vs less than 1 mm). Thorne (1939) noted that his specimens are much larger than those from the type locality. Andrássy (1961) noted that the specimens described by Thorne (1939) differ somewhat from those of the type population by their larger body, longer tail, and presence of a single precloacal supplement. He further noted that they may belong to another species.

DISTRIBUTION

Described from humus in Plummer’s Island, Potomac River, near the District of Columbia, USA ( Cobb 1920). Reported from humus around native plants in Virginia and Utah, USA ( Thorne 1939), from soil around roots of brush and trees in South Dakota, USA ( Thorne 1974), and from the rhizosphere of undetermined plants in the USA, England and the Netherlands ( Goodey 1963). Kuzmin & Gagarin (1990) noted that this species occurs in Taymyr and Severnaya Zemlya, Russia.