Enchodelus macrodorus Thorne 1939
Creators: name: Guerrero, Pablo
name: Santiago, Reyes Peña-
Publisher: name: Zenodo
Year: 2007
Subjects: Biodiversity
Taxonomy
Animalia
Nematoda
Adenophorea
Dorylaimida
Dorylaimidae
Enchodelus
Enchodelus macrodorus

description: Enchodelus macrodorus (de Man, 1880) Thorne, 1939=Dorylaimus macrodorusde Man, 1880 =Dorylaimus (Doryllium) macrodorus (de Man, 1880)Ditlevsen, 1928 =Dorylaimellus macrodorus (de Man, 1880)Thorne & Swanger, 1936
(Figs 10, 11)
Nine females, five of them mounted on a slide labelled Enchodelus macrodorus 1h, and collected from Aspen Creek, Utah, USA, on 22 June 1932, in very good condition. The other four females mounted on slide labelled Enchodelus macrodorus 1d, and collected from Strawberry Reservoir, Utah, USA, in sage brush soil, in September, 1924, three of them also in good condition.
MEASUREMENTS
See Table 4.
DESCRIPTION
Female
Moderately stout nematodes of medium size, 1.5- 1.7 mm long. Habitus after fixation slightly ventrad curved. Body cylindrical, tapering towards both ends but more so towards anterior. Cuticle 3.0-4.5 µ m thick at anterior region, 3.5-4.5 µ m at mid-body and 8.5-11.0 µ m at tail; its outer layer practically smooth or bearing very fine transverse striations, and much thinner than inner, specially at level of tail. Lateral chord very narrow, less than one-tenth of mid-body diam., lacking any particular differentiation. Lateral pores obscure. Lip region rounded, offset by a marked depression, 2.5-3.5 times as broad as high and ca one-third of body diam. at neck base. Lips amalgamated, perioral area hardly differentiated; labial and cephalic papillae visibly protruding from lip region contour. Amphid fovea cup-shaped, opening at level of cephalic depression and occupying one-half to two-thirds of corresponding body diam. Cheilostom a truncate cone, with thickened walls. Odontostyle long and slender, with distinct walls and narrow lumen; 11- 18 times as long as wide or 1.9-2.4 times as long as lip region diam.; aperture small, ca one-twelfth of total length. Odontophore bearing distinct flanges occupying ca half of total length; scarcely longer (1.0-1.2 times) than odontostyle. Guiding ring double, at 25-28 µ m or 1.3-1.5 times lip region diam. from anterior end. Pharynx consisting of slender but well muscled anterior portion expanding gradually into basal expansion at 59-62% of total neck length, reaching maximum diam. at 64- 68%; pharyngeal expansion occupying 35-38% of total neck length, and one-half to two-thirds of corresponding body diam. Pharyngeal gland nuclei located as follows: DN = 65-68; S 1 N 1 = 24-36; S 1 N 2 = 27-37; S 2 N 1 = 54-59; S 2 N 2 = 57-61. Base of pharyngeal expansion surrounded by weak membrane-like structure. Cardia very small, rounded conoid, and wider than long (12- 19 × 9-16 µ m). Genital system didelphic-amphidelphic, with both branches equally and well developed. Ovaries relatively large, 83-188 µ m long, but usually not reaching sphincter level; oocytes first in two or more rows, then one. Oviduct 97-159 µ m long, consisting of slender portion with prismatic cells and well developed pars dilatata with distinct lumen. Sphincter distinct, located between oviduct and uterus. Uterus short, tripartite: wider proximal portion having distinct lumen followed by a narrower intermediate region with narrow lumen joining a small spheroid pars dilatata distalis; length 61-143 µ m or 1.1-2.0 times body diam. at its level. Sperm not observed in genital tract. Two eggs observed inside both genital branches of one female, measuring 57 × 92 and 55 × 87 µ m. Vagina extending inwards to ca half (47-57%) of body diam.; pars proximalis 17-21 × 21-27 µ m, with almost straight or somewhat sigmoid walls, and enveloped by moderately developed circular musculature; pars refringens with (in lateral view) two close trapezoidal sclerotisations with a combined width of 19-20 µ m; pars distalis short, 4.0-6.0 µ m long. Vulva a transverse slit. Prerectum long, 3.9-5.8 anal body diam. Rectum almost equal to anal body diam. Tail short rounded to hemispheroid. Two pairs of caudal pores, both subterminal, one subdorsal, another subventral; most specimens bearing some small irregularities between inner and outer layers of cuticle, mainly at ventral side of the tail, sometimes appearing as vesicles in dorsal view.
Male
Not seen.
DIAGNOSIS
Enchodelus macrodorus is distinguished by its body 1.5-1.7 mm long, lip region offset by marked depression and 17.5-20 µ m diam., odontostyle 38-43 µ m long or 1.9-2.4 times the lip region diam., odontophore provided with distinct basal flanges and slightly longer (1.0-1.2 times) than odontostyle, neck length 303-345 µ m long, pharyngeal expansion 111-130 µ m long and occupying 35-38% of total neck length, female genital system amphidelphic, uterus tripartite, pars refringens vaginae with two sclerotisations, vulva in form of a transverse slit and uniquely anterior (V = 41-44), and tail short rounded to hemispherical (18-24 µ m, c = 68-91, cļ = 0.5-0.6).
REMARKS
Thorne (1939) wrote that this species was “common at elevations of 8,000 to 12,000 feet in Wasatch and Uinta Mountains, Utah, U.S.A.”, and, although he did not mention the two localities from where the specimens studied herein were collected, it seems more than likely that this material belongs to that studied by him since his morphometric and morphological details fit perfectly with those given above. Thorne (1939) described the male of the species but unfortunately nomale was found in the two available slides from the USDA Nematode Collection.
The present description and that of Thorne (1939) of American specimens of E. macrodorus apparently fit very well that of de Man (1880), although, of course, the latter is not very detailed.
Enchodelus macrodorus seems to be very widely distributed in Holartic areas.
description: Published as part of Guerrero, Pablo & Santiago, Reyes Peña-, 2007, Redescription of Enchodelus species studied by Thorne in 1939 (Dorylaimida: Nordiidae), pp. 93-121 in Nematology 9 (1) on pages 112-116, DOI: 10.1163/156854107779969646, http://zenodo.org/record/8111793