Enchodelus saxifragae, Popovici, 1995

Popovici, Iuliana, 1995, New Species Of Tubixaba And Enchodelus (Nematoda: Dorylaimida) From Romania, Nematologica 41, pp. 435-448 : 442-445

Enchodelus saxifragae sp. n.

( Fig. 4 A-E; measurements in Table III).

Female (n = 5): Body slightly curved ventrad upon fixation. Cuticle 2.5-5 Jlm thick at midbody, 7-9.5 pm on dorsal side at tail base, 7-12 J. 1m on tail tip. Lateral chord one-fifth to one-sixth of body diameter.

Lips rounded, hemispheroidal, distinctly set off from body ( Fig. 4 A-B). Amphids stirrup-shaped, their aperture 7.5-10 J. 1m. Guiding ring "double", 1.2 head-widths from anterior end. Odontostyle long, 1.8-2 widths of lip region, its aperture occupying 1 / 10 of its length ( Fig. 4B ). Odontophore 1.1-1.3 the odontostyle length with well developed basal flanges, maximum flange width 5-8 pm at its base.

Nerve ring surrounds the anterior part of oesophagus at 40-44% of its length from anterior end. Cardia short, hemispheroidal, 12.5-19 gm long. The oesophagus ( Fig. 4 A ) begins to widen at 38-41 % of its length from anterior end. Maximum oesophagus width 31-35 gum, half the corresponding body diameter at the base of oesophagus. The distance DO-DN is 12.5-15 gm, or 3.5% of the oesophagus length. Locations of the oesophageal gland nuclei as follows (n = 5): DO = 62.4 (60.7-65.2); DN = 67.6 (64.4-68.9); S1N1 = 74.6 (73.1-77.1); SIN2 = 76 (74.8-77.8); S2N = 86.7 (86-87.4); K = 85.5 (83.6-92.1).

Reproductive system didelphic: gonads opposed, reflexed 44-65%, oocytes in a single row ( Fig. 4C ). A sphincter separates oviduct and uterus. Eggs measuring 110 x 48 pm and 112.5 x 42 J.1mare present one at a time in the uteri in two specimens. Vulva a transverse, pre-equatorial slit, vagina with sclerotized walls extends to 40-55% of the corresponding body width, with well sclerotized heart-shaped pieces at vulva-vagina junction.

Rectum 0.6-1.1 and prerectum 4-5 anal body widths long ( Fig. 4D ). Tail smoothly rounded, 0.6-0.8 anal body width long, with two pairs of caudal pores.

Male (n = 9): Body similar to female but with the posterior part more curved ventrad. Diorchic with testes oppposed. Spicules arcuate, fairly stout ( Fig. 4 E ). Lateral guiding pieces almost straight, 9-12.5 gm long. Supplements consisting of an adanal pair and a row of 13-16 regularly spaced ventromedian ones, one to three of them within the range of spicules.

Juvenile (second stage?) (n = 4): L = 1.08-1.40 mm; a = 19.8-33.3; b = 3.5-4.8; c = 43.2-57.7; c' = 0.67-1; odontostyle = 20-32.5 gum; odontophore = 32.5-40 gum; replacement odontostyle = 25-44 pm.

Juvenile (third stage) (n = 1): L = 1.76 mm; a = 32; b = 5.5; c = 56; c' = 0.86; odontostyle = 30 gm; odontophore = 45 replacement odontostyle = 37.5 pm.

Type habitat and locality: Type population collected in June, 1987 from a subalpine grassland on limestone, under Saxifraga moschata Wulf. , at 1950-2000

m altitude, in the Retezatul Mic Mountains (Piatra Iorgovanului and Albele) (the Southern Carpathians), Romania.

Type specimens: Holotype and two paratypes (female, male) on slides no. 49997 and 49998 deposited in the Collection of the Natural Historical Museum " Gr. Antipa " Bucharest, Romania. One female and one male in the Nematology Department, Agricultural University Wageningen, the Netherlands; two males at Rothamsted Experimental Station, Harpenden, England; other specimens deposited in the Department of Ecology, Biological Research Institute, Cluj-Napoca, Romania.

Diagnosis: The species Enchodelus saxifragae sp. n. is distinguished by its long body, about 2 mm, lip region distinctly set off, lips rounded, odontostyle fairly long, 1.6-2 head-widths long, vulva pre-equatorial, tail short, smoothly rounded. Males have long spicules (56-70 pm) and 13-16 ventromedian supplements.

Differential diagnosis: Enchodelus saxifragae sp. n. is close to E. distinctus Ahmad & Jairajpuri, 1980, E. hopedoroides Altherr, 1963 and E. ponorensis sp. n. by having lip region distinctly set off from body. It differs from E. distinctus by its longer body (L = 1.85 mm, only one female, in E. distinctus), longer odontostyle (37.5-40 pm vs 36 gm), lack of oesophago-intestinal disc (present in E. distinctus), vulva pre-equatorial vs post-equatorial, and by the presence of male (not found in E. distinctus). The new species differs from E. hopedoroides by its longer body (1.42-1.85 mm in E. hopedoroides), hemispheroidal lips (angular in E. hopedoroides), longer odontostyle (37.5-40 vs 33 J. 1 m) and odontophore (45-52.5 vs 43 pm) and by the presence of male (not found in E. hopedoroides). E. saxifragae sp. n. can be distinghuised from E. ponorensis sp. n. by its longer body (L = 2.03-2.35 mm vs L = 1.65-2.07 mm), odontostyle and odontophore (37.5-40 vs 23-25 Ujn, respectively 45-52.5 vs 32.5-37.5 J. 1 m), wider and more set off lip region, a more posterior position of fixed guiding ring (see Tables II and III) as well as shorter and smoothly rounded tail (25-32.5 vs 35-45 J. 1 m), and in the presence of male (absent in E. ponorensis sp. n.).

Remarks: Enchodelus saxifragae sp. n. was found together with E. macrodorus (de Man, 1880) Thorne, 1939, but it could be easily distinguished from this cosmopolitan species by its longer body, distinctly set off lip region and males with more numerous ventromedian supplements.

Figures

Fig. 4. Enchodelussaxifragaesp. n. A, Anterior part ofbody; B, Lateral view of head; C, Vulva, vaginal region and posterior genital branch; D, Posterior end (female);E, Posterior end (male).