Epacrolaimus reyesi, Pedram, Majid, Pourjam, Ebrahim & Vinciguerra, Maria T., 2012

Pedram, Majid, Pourjam, Ebrahim & Vinciguerra, Maria T., 2012, Description of a new species of the rare genus Epacrolaimus Andrássy, 2000 (Dorylaimida, Aporcelaimidae) and new data on male of Paraxonchium laetificans (Andrássy, 1956) Altherr & Loof, 1969 (Dorylaimida, Paraxonchiidae) from Iran, Zootaxa 3327, pp. 53-61 : 54-57

Epacrolaimus reyesi n. sp. ( Figs. 1 & 2 )

Measurements. See table 1.

Paratype females Holotype Paratype males Morphological description. FEMALE. Body very long, rather slender, tapering gradually anteriorly. Cuticle with fine criss-cross lines, comprising a thin outer, very refractive layer and a very thick inner part composed of two or three layers with the same weak refraction, 8–11 µm thick at the level of labial region, 8–13 µm at mid body and 20–22 µm at anus. Cuticle in the neck region crossed by 5–6 ventral and as many dorsal canals. Lip region 2.5– 3.0 times wider than high, separated from the rest of body by a sharp constriction; lips well separated from each other, ovoid, provided with small inner liplets only slightly protruding. The liplets, when focusing, on their inner surface appear crossed by a kind of longitudinal corrugation ( Fig. 1 , B & C). Anterior circle of 6 inner labial papillae hardly visible; posterior circle of 10 (outer labial and cephalic) papillae well developed. Amphidial fovea cup shaped, with slit-like aperture bordering lip region base, ca 45% of lip region diam. wide. Odontostyle small compared to body size, ca 4.5 times longer than wide at base; its aperture (ca 85% of its length) affects a large part of the dorsal and lateral odontostyle surface, thus assuming an arched aspect and giving a particularly acuminate aspect to the odontostyle; odontophore rod-like and flexible. Guiding ring plicate and variable in position depending on the stylet position. Nerve ring encircling the anterior narrow part of pharynx. Pharynx muscular throughout its length, gradually widening at ca 25% of its length. The position of the gland nuclei according to Andrássy (1998) are as follows (n=2): DN: 40.5–42.5%, AS 1: Not clearly seen, AS 2: 32–36%; PS1 and PS2, at about the same level: 60.0–63.5%. Cardia hemispherical to conical, 30–40 µm wide and 27–35 µm high. Prerectum 2.4–2.7 times anal body width long and rectum 0.8–0.9 times anal body width long. Reproductive system amphidelphic with reflexed gonads, the two branches more or less equally developed; each composed of a 350–375 µm long ovary, 487–675 µm long oviduct, separated from uterus by a sphincter. In a single female at the junction between oviduct and ovary, in both branches, a deep constriction separating the ovary from a wide chamber where the most mature oocyte is contained was observed ( Fig. 1 H), probably a temporary dilatation due to the passage of the oocyte into the oviduct, since it lacks in the other specimens. Uterus a simple tube, 460–712 µm long, containing 5–6×2–3 µm sized sperm and 170–205×105 µm sized eggs (1– 3 eggs were observed within the anterior genital tract and 1 in the posterior one); vagina perpendicular to body axis, 50–62 % of corresponding body width long; pars distalis vaginae 15 µm long, more refractive than adjacent cuticle; pars refringens vaginae 20–23 µm long and 10 µm wide with trapezoid sclerotized pieces; pars proximalis vaginae 80–173 µm long and 55–75 µm wide. Vulva a transverse slit surrounded by a slightly wrinkled cuticle. Tail dorsally convex, with rounded terminus, clearly shorter than anal body width long; its hyaline region 12–20 μm thick.

MALE. As abundant and common as females and functional. General morphology similar to that of female, except posterior end more ventrally curved. Genital system diorchic, spicules massive, dorylaimoid, 3.8–4.6 times longer than wide. The precloacal pair of supplements located at 25 μm distance from cloacal opening and a series of 9 more or less regularly spaced ventromedian supplements ending at 153–185 μm distance from cloacal opening. Intestine joins prerectum at ca 50 μm distance from the anteriormost supplement. The ventromedian supplements row 202 μm long. Tail similar to that of female.

Type habitat and locality. Soil from rhizosphere of forest trees ( Fagus orientalis Lipsky ), Salaheddin Kola, Mazandaran province, northern Iran.

Type material. Holotype female and one paratype male deposited at Nematology Laboratory of Faculty of Agriculture of Tarbiat Modares University, Tehran, Iran. One paratype female and one paratype male deposited at the USDA Nematode Collection, Beltsville, MD, USA and one paratype female at the section of Animal Biology, Department of Biological Geological and Environmental Sciences, of the University of Catania ( Italy).

Diagnosis and relationships. Epacrolaimus reyesi n. sp. is an amphimictic species characterised by having a long body (7.23–7.87 mm), lip region separated by a sharp constriction by the adjoining body, lips well distinct, liplets provided with longitudinal corrugation on their inner surface, 19–22 µm long odontostyle with a wide, arched, aperture occupying ca 85% of its length, pharynx expanding at about 25% of its length, female reproductive apparatus didelphic with reflexed gonad, tail convex with round terminus in both sexes, 9 separated ventromedian supplements in males and 135–145 µm long spicules. The new species is compared with the two other known species of the genus, namely E. declinatoaculeatus , which it resembles more, and E. imperator . Compared to the former, the new species has a different lip region, a wider body (172–178 vs 124–128 µm at midbody region, a = 42.0–44.5 vs 47–62), shorter (55–67 vs. 63–75 µm) rounded tail vs bluntly conoid, rounded on tip or with a minute peg, shorter spicules (135–145 vs 215 µm) and fewer male copulatory supplements (9 vs 12). Compared to the latter species, E. reyesi n. sp. has a wider body at mid region (172–178 vs 156–160 µm), shorter (55–67 vs 84 µm), rounded (vs convex–conoid, slightly subdigitate on tip) tail, shorter spicules (135–145 vs 202–210 µm), shorter tail in males (58–65 vs 70–86 µm) and fewer male supplements (9 vs 14–16). From both species, E. reyesi n. sp. differs in the longitudinal corrugation of liplets.

Etymology. The species is named in honor of Prof. Reyes Peña-Santiago, the well-known authority on the taxonomy of Dorylaimida .

Figures

FIGURE 1. Epacrolaimus reyesi n. sp. A: Neck region; B & C: Anterior end in detail D: Female genital tract with sperm and a mature egg; E: Vagina and wrinkled vulva region; F: Male posterior end; G: Female tail; H: Peculiar aspect of the gonad in a female.

FIGURE 2. Epacrolaimus reyesi n. sp. A: Female anterior genital branch; B: Anterior end; C: Detail of lip region; D: Vagina and wrinkled vulva region; E: Female tail; F: Male posterior region.