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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Arctidorylaimus

Arctidorylaimus Mulvey & Anderson, 1979 (ref. ID; 5942 original paper)

Family Arctidorylaimidae (ref. ID; 5942 original paper)

ref. ID; 5942

Diagnosis

Arctidorylaimidae. Head broadly rounded, offset, lips delineated. Labial and caudal papillae of sexes elevated. Stylet guiding ring double, posterior ring fixed, anterior ring extendable. Expanded basal bulb of esophagus more than half of total length. Female didelphic, ovaries opposed reflexed. Spermatheca large oblong. Vuval opening elliptical, greatest diameter along longitudinal axis. Male diorchic, testes opposed, outstretched. Prerectum beginning anterior to supplements. Copulation pad ('kopulationshocker') present. Spicules robust, arcuate, widest at proximal half. (ref. ID; 5942)

Note

Andrassy (1976), in the most recent classification of the phylum Nematoda, recognizes 10 families in the Dorylaimoidea. All species with longitudinal body ridges and double guiding ring are placed in the Dorylaimidae, which have in common females with long filiform tails and males with short tails and small, numerous supplements in a contiguous series or fascicles. As defined, Arctidorylaimus cannot be placed in this or any other of the nine families in this classification without emendation and confusing relationships. Accrodingly, we propose to establish a new family, Arctidorylaimidae, in the Dorylaimoidea (Dorylaimida), designating Arctidorylaimus as the types genus. (ref. ID; 5942)

Type species

Arctidorylaimus arcticus Mulvey & Anderson, 1979 (ref. ID; 5942)
  1. Arctidorylaimus arcticus Mulvey & Anderson, 1979 (ref. ID; 5942 original paper)

Arctidorylaimus arcticus Mulvey & Anderson, 1979 (ref. ID; 5942 original paper)

Descriptions

  • Female: Body ventrally arcuate, varying in degree of curvature posterior to vagina. Cuticle surface with 48-50 longitudinal ridges and with fine transverse annules, being most distinct on neck and tail. Lateral cord granular, vacuolated, about a third of body width. Cuticular pores present along esophageal region observed in following descending sequence: a lateral papilla at base of each amphid pouch, a circlet of four (dorsal, ventral, and two lateral) near base of stylet, followed by two dorsal and ventral pairs, three circlets of four to posterior of nerve ring, one dorsal and ventral within a body width posterior to level of dorsal gland duct. Ventral and laterosubdorsal body pores present, generally indistinct in female, more pronounced in male; caudal pores absent. Lip region offset, lips uniform, separate, each bearing an apical papilla, lateral lips with one on outer contour, submedian lips each with two on outer contour. Amphid stirrup shaped, usually weakly delineated, apertures as wide as neck at base of head. Stylet dorylaimoid, aperture about a third of stylet length, extension regular. Vestibule expanded, guiding ring double, posterior ring fixed, anterior ring extendable, collapsed to form a single ring when stylet fully retracted. Esophagus dorylaimoid, corpus narrow, expanding near middle of esophagus into elongate, cylindrical basal bulb containing five gland cells (evidenced by duct orifices). Duct of dorsal gland at anterior end of esophagus near junction with corpus, two subventral ducts near middle of bulb, separated by about a body width from posterior end of esophagus. Cardia conoid, multicellular, enclosed by intestinal cells. Intestine polycytous, cells about 14-23 µm in diameter, cytoplasm densely globular. Distal end of rectum at junction with prerectum encircled by large spinde-shaped sphincter. Tail conoid, ventrally arcuate, tapering to narrowly rounded or pointed terminus. Posterior third of tail bearing a pair of lateral and subdorsal elevated papillae. Female didelphic, ovaries opposed, with single or double flexure. Germinal zone of ovary short, germ cells in multiple rows, oocytes in tandem. Vulva aperture elliptic, greatest diameter longitudinal, lips to protuberant. At junction with vagina cuticle modified into a thick ring (vulva plates). Vagina thick walled, lumen quadriradiate, encircled by a heavily muscular sphincter. Spermatheca 130-170 µm long, filled with fusiform or rod-shaped sperms, irregular in crosss section. (ref. ID; 5942)
  • Male: Male similar to female except for sexual characteristics. Body linear to ventrally arcuate, posterior end recurved. Testes two, opposed, germ cells in multiple rows. Spicules stout, proximal half conoid, greatest width 13-20 µm, distal part subcylindrical with inner sclerotization, terminus tapered, cleft. Ventromedian supplements large, mammillate, spaced arranged in two groups separated by about a body width. Copulation pad present, coarsely annulated, immediately anterior to supplements. Submedian ventral papillae five to seven, spaced with range of supplements. Laterosubdorsal body pores extending anteriorly from near level of cloaca, ventral pores from supplements, generally elevated in posterior third of body. Prerectum long, beginning about a body width anterior to supplements. Tail conoid, ventrally arcuate, bearing four pairs of papillae, a lateral and subdorsal pair in posterior third (as in females) a subdorsal and subventral pair in anterior half. (ref. ID; 5942)

    Notes

    Arctidorylamius arcticus n. sp. has a combination of characters no represented in any genus of the Dorylaimoidea. The presence of longitudinal body ridges, double guiding ring and long prerectum of the male most closely relates with this species to those (Dorylaimidae) of the genera Dorylaimus Dujardin, 1845, Ischiodorylaimus Andrassy, 1969, and Paradorylaimus Andrassy, 1960. Arctidorylaimus arcticus differs significantly from the species of these genera, however, in the similar form of the male and female tails and by the relatively few, spaced, large supplements of the male. We therefore propose a new genus, Arctidorylaimus, to accommodate A. arcticus and clarify its relationships. Idiodorylaimus annulatiformis Loof, 1973 (Dorylaimidae) also has longitudinal body ridges, which are absent in other species of Idiodorylaimus. All species of this genus have sexes with dissimilar tails and males with contiguous supplements. (ref. ID; 5942)

    Type deposition

  • Holotype (female): L=4.6 mm; a=41; b=5.5; c=41; V=45. Stylet length=35 µm. Prerectum length=150 µm. Tail length 115 µm. Collection No.6628. Type slides No.243. Deposited in Canadian National Collection of Nematodes (CNCN), Ottawa, Canada. Collected from bottom mud of Jamieson Channel, Mackenzie Delta, Northwest Territories. (ref. ID; 5942)
  • Allotype (male): L=4.2 mm; a=49; b=5.3; c=47. Stylet length=35 µm. Spicule length=78 µm. Tail length=90 µm. Ventromedian supplements=9+2. Collection No. 6628. Type slide No.243a. Deposited in the CNCN, Ottawa, Canada. Habitat and locality as for holotype. (ref. ID; 5942)
  • Paratypes (20 females, 10 males): Collection Nos.6628, 6759, 6630, 6688, 6703. Deposited in the CNCN, Ottawa, Canada. (ref. ID; 5942)

    Measurements

  • Female: L=4.2(3.9-4.6) mm; a=49(43-55); b=5.1(4.7-5.8); c=40(36-46); V=46(40-50). Stylet length=35(33-36) µm (n=10). Eggs=95-110x40-50 µm. Prerectum length=120-150 µm. Tail length=105(100-150) µm. Midbody cuticle thickness=8-9 µm (n=10). (ref. ID; 5942)
  • Male: L=3.9(3.6-4.3) mm; a=54(48-61); b=5.3(5.1-5.5); c=43(39-48). Stylet length 34(33-35) µm. Supplements 7-11 + 2 (preanal). Tail length=92(80-110) µm. Spicule length 76(72-80) µm (n=10). (ref. ID; 5942)