Enchodelus parahopedoroides, Ciobanu & Popovici & Guerrero & Santiago, 2010

Ciobanu, Marcel, Popovici, Iuliana, Guerrero, Pablo & Santiago, Reyes Peña-, 2010, Nematodes of the order Dorylaimida from Romania. The genus Enchodelus Thorne, 1939. 2. Species with rounded tail and medium-sized odontostyle, Nematology 12 (3), pp. 381-397 : 388-394

Enchodelus parahopedoroides * sp. n.

( Figs 3-5 )

MATERIAL EXAMINED

Three females from the Bucegi Mountains , three females from the Retezat Mountains , one male from Vlădeasa Mountain , and one male from Bihor Mountains , all in acceptable condition.

MEASUREMENTS

See Table 4.

DESCRIPTION

Female

Moderately slender nematodes of medium size, 1.44- 1.64 mm long. Habitus after fixation curved ventrad, Cshaped. Body cylindrical, tapering towards both ends, but more so anteriorly. Cuticle 2.0-2.5 µm in anterior region, 2.0-3.0 µm at mid-body and 7.0-7.5 µm on tail; its outer layer with very fine transverse striations and much thinner than inner one, especially on tail. Lateral chord 4.5- 7.0 µm wide or occupying 8-12% of mid-body diam., lacking any particular differentiation. Lateral pores obscure, one dorsal and one ventral pore prominent at odontostyle level. Lip region more or less rounded, offset by a distinct depression, 2.8-3.1 times as broad as high and ca one-third (32-36%) of body diam. at neck base. Lips amalgamated, labial and cephalic papillae visible, protruding above cephalic contour. Amphid fovea cup-shaped, opening at level of cephalic depression, occupying 8-10 µm or ca one-half (42-51%) of corresponding body diam. Cheilostom curly-bracket-shaped. Odontostyle comparatively robust, 11-14 times as long as wide, 1.5-1.6 times longer than lip region diam. or 1.6-2.0% of total body length, aperture small, 4-5 µm long or 14-17% of total length. Odontophore 1.4-1.6 times as long as odontostyle, with basal thickenings or flanges. Guiding ring double, located at 17-20 µm or 1.0-1.1 times lip region diam. from anterior end. Pharynx consisting of a slender muscular anterior portion expanding gradually, pharyngeal expansion occupying ca two-fifths (39-41%) of total neck length and ca one-half of corresponding body diam. Pharyngeal gland nuclei located as follows: DN = 64-67; S 1 N 1 obscure; S 1 N 2 = 75-78; S 2 N = 85-87. Cardia rounded conoid, nearly as long as broad, (12-18) × (10-13) µm. Genital system didelphic-amphidelphic, both branches equally and well developed, anterior branch 240- 293 µm, posterior branch 215-280 µm long. Ovaries 53- 140 µm long, not reaching sphincter level; oocytes initially in two or more rows, then in one row. Oviduct 65- 105 µm or 1.2-1.9 corresponding body diam. long, consisting of a slender portion with prismatic cells and a moderately developed pars dilatata with visible lumen. Sphincter prominent, located between oviduct and uterus. Uterus long, 133-170 µm or 2.4-3.1 corresponding body diam., sometimes twisted, tripartite, i.e.: consisting of a wider proximal region with distinct lumen followed by a narrower and shorter intermediate portion with narrow lumen and surrounded by a cluster of hyaline cells, and ending with a well developed spheroid pars dilatata distalis. Vagina extending inwards 27-32 µm or 47-58% of body diam., pars proximalis longer than broad, (18-22) × (11-15) µm, with sigmoid to straight walls and enveloped by weak circular musculature; pars refringens with (in lateral view) two trapezoidal sclerotisations measuring (3.0- 4.5) × (6-8) µm and with a combined width of 12-15 µm; pars distalis 4.0-5.0 µm long. Vulva a transverse oval slit, preceded by a shallow depression in body surface. Prerectum 3.9-5.7 and rectum 0.9-1.4 anal body diam. long. Tail rounded conoid, in one specimen with a few small saccate bodies, inner cuticle layer marked by radial striation, its ventral margin slightly irregular, barely separated from outer layer. Two pairs of subterminal caudal pores, one subdorsal, another practically lateral.

Male (see remarks)

General morphology similar to that of female, but with more slender body, narrower lip region and slightly shorter odontophore. Genital system diorchic, with opposed testes. In addition to adcloacal pair at 11 or 10.5 µm from cloacal aperture, presence of series of nine ventromedian supplements 10-24 µm apart, posteriormost supplement located at 31 or 32.5 µm from adcloacal pair, barely in anterior to, or at level of, anterior end of spicules. Spicules well curved ventrad, rather robust, ca 5.1 or 6.0 times as long as wide or 1.6 or 1.9 anal body diam. long. Lateral guiding pieces 9.5 or 11.5 µm, ca 4.8 or 3.8 times as long as wide. Tail similar to that of female.

DIAGNOSIS AND RELATIONSHIPS

Enchodelus parahopedoroides sp. n. is distinguished by its 1.44-1.64 mm long body, lip region 17.0-18.5 µm diam. and offset by a marked depression, odontostyle 26-28 µm or 1.5-1.6 lip region diam. long and 1.6- 2.0% of total body length, odontophore 40-43 µm long and with distinct basal knobs and flanges, neck 300- 328 µm long, pharyngeal expansion 120-130 µm long or 39-41% of total neck length, female genital system amphidelphic, uterus long and tripartite, pars refringens vaginae with two trapezoidal sclerotisations, V = 45- 52, tail rounded conoid (20-24 µm long, c = 63-80, cļ = 0.6-0.8), spicules 59-67 µm long, and nine spaced ventromedian supplements starting just anterior to, or at level of, anterior end of spicules.

Enchodelus parahopedoroides sp. n. is very similar to E. hopedoroides Altherr, 1963 (see description by Guerrero et al., 2008b), from which it differs in its narrower lateral chord (4.5-7.0 µm or 8-12% of body diam. vs 8-16 µm or 11-27% of body diam., respectively), shorter odontostyle (26-28 vs 31-34 µm, n = 23), pars refringens vaginae without vs with two massive and granular appearing pieces, vulva more posterior (V = 45-52 vs = 40-47), and female tail lacking abundant saccate bodies and any peculiar differentiation of the cuticle vs saccate bodies abundant and inner cuticle layer divided into two by a discontinuity, its ventral margin rather irregular and somewhat separated from the outer layer. In spite of the high similarity between both species, there are three features (odontostyle length, nature of pars refringens vaginae and female tail) that support the proposal of a new taxon for the Romanian material.

In having an odontostyle less than 30 µm long and rounded tail, the new species is also close to E. altherri Vinciguerra & de Francisci, 1973 , E. ameliae Guerrero, Liébanas & Peña-Santiago, 2008 , E. analatus (Ditlevsen, 1927) Thorne, 1939 , E. arcticus Nesterov, 1976 , E. georgiensis Eliava, Tskitishvili & Bagathuria, 2006 , E. hopedorus (Thorne, 1929) Thorne, 1939 , E. longispiculus Guerrero, Liébanas & Peña-Santiago, 2008 and E. ponorensis Popovici, 1995 . It differs from E. altherri in its longer body (vs 1.18-1.38 mm), comparatively longer odontostyle at 1.5-1.6 vs 1.8-2.0 lip region diam. long (i.e., 1.8 according to the original Figure 2A of E. altherri and 2.0 according to the original description), longer neck (vs 236-276 µm, as calculated from original description), vagina with well developed pars refringens (vs “vulva debolmente ispessita”), tail of both female and male more rounded vs conoid, shorter (vs c = 41- 59, cļ = 1.0, calculated from original illustrations) and lacking saccate bodies vs 3-8 saccate bodies present, and longer spicules (vs 50-52 µm). From E. ameliae in its less marked lip region (vs offset by constriction), shorter odontostyle (vs 30-33 µm, n = 11, including females and males), longer neck (vs 268-307 µm) and pharyngeal expansion (vs 95-107 µm), and fewer (vs 11-14) ventromedian supplements, the posteriormost located barely anterior to, or at level of, the anterior end of the spicules vs one or two within the range of the spicules. From E. analatus in its shorter odontostyle (vs 30-34 µm), pars refringens vaginae present vs absent and shorter female tail (vs c = 40-55, cļ = 0.8-1.1) which lacks vs presence of saccate bodies. From E. arcticus in its broader lip region (vs 12 µm, as inferred from original description), longer odontophore (vs up to 36 µm, as inferred from original description) and ventromedian supplements present vs reportedly absent (!). From E. georgiensis in its longer body (vs 0.88-1.10 mm), broader lip region (vs 12 µm), longer odontophore (vs 35-37 µm) and longer spicules (vs 36- 44 µm). From E. hopedorus in its broader female lip region (vs 14.5-16 µm), comparatively shorter odontostyle (vs 1.9-2.2 times the lip region diam.), longer pharyngeal expansion (vs 33-38% of total neck length) and shorter female tail (vs 27-39 µm, c = 41-53) lacking vs bearing abundant saccate bodies. From E. longispiculus in its more slender body (a = 26-30 vs 17-25; body diam. at mid-body = 50-57 vs 64-80 µm), longer pharyngeal expansion (vs 77-114 µm or 28-37% of total neck length, n = 40), somewhat more posterior vulva (vs V = 41- 48) and posteriormost ventromedian supplement located barely anterior to, or at level of, anterior end of spicules (vs two posteriormost, occasionally only one, within range of spicules). Finally, from E. ponorensis , the other Romanian species, in its shorter body (vs 1.6-2.1 mm), narrower lateral chord (vs one-fourth of mid-body diam.) broader female lip region (vs 15-16 µm), longer odontostyle (vs 23-25 µm), uterus tripartite vs bipartite, and shorter female tail (vs 35-45 µm, c = 41-56, cļ = 0.9- 1.3).

TYPE HABITAT AND LOCALITY

Cliff vegetation, Caraiman Peak, Bucegi Mountains (Southern Romanian Carpathians); site 5 in Table 1.

OTHER HABITATS AND LOCALITIES

Cliff vegetation on Albele Peak, Retezat Mountains (Southern Romanian Carpathians), mountainous grassland at Dealul Caprei, Vlădeasa Mountain (Western Romanian Carpathians) and spruce forest in a swamp area on the Padiş karstic plateau, Bihor Mountains (Western Romanian Carpathians); sites 9, 11 and 4 in Table 1.

TYPE MATERIAL

Holotype female on slide 1317 and one paratype female (1318/c) deposited in the nematode collection of the Institute of Biological Research, Cluj-Napoca, Romania. Slide 1316 containing one paratype female deposited in the nematode collection of Departamento de Biología Animal, Biología Vegetal y Ecología, University of Jaén, Spain .

REMARKS

Some doubts persist as to the conspecifity of the two males examined, which were collected from the Vlădeasa and Bihor Mountains whilst the females came from the Bucegi and Retezat Mountains, as there are some morphometrical differences, particularly their narrower lip region in addition to their different geographical origin. Nevertheless, some significant features, such as odontostyle and pharyngeal expansion lengths are similar to those found in females and serve to distinguish the males from E. longispiculus , the most similar species. In addition, as mentioned above, the male posteriormost ventromedian supplement is located barely anterior to, or at level of, the anterior end of the spicule, whereas in other species at least one ventromedian supplement is present within the range of the spicules. Thus, the males are provisionally considered to belong to the same species as the females from Bucegi and Retezat Mountains.

Figures

Fig. 3. Enchodelus parahopedoroides sp. n. A: Anterior region in median, lateral view; B: Lip region in surface, lateral view; C: Neck; D: Female, posterior body region; E: Female, genital system; F: Female, caudal region; G: Vagina; H: Male, posterior body region; I: Male, caudal region; J: Oviduct-uterus junction.

Fig. 4. Enchodelus parahopedoroides sp. n. A, B: Anterior region in median, lateral view; C: Female, posterior body region; D: Female, posterior genital branch; E, F: Vagina; G: Oviduct-uterus junction; H: Female, caudal region. (Scale bars: A, B, E, F-H = 10 µm; C, D = 20 µm.)

Fig. 5. Enchodelus parahopedoroides sp. n. A, B: Pharyngeal expansion; C, D: Cardia; E: Male, posterior body region; F, G: Male, caudal region. (Scale bars: A, B, E = 20 µm; C, D, F, G = 10 µm.)

Fig. 2. Enchodelus lucinensis Popovici, 1978. A: Female, entire; B, C: Anterior region in median, lateral view; D: Neck region; E, F: Vagina; G, H: Female, caudal region; I: Male, caudal region. (Scale bars: A = 200 µm; B, C, E-I = 10 µm; D = 100 µm.)