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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Rhabditis

Rhabditis Dujardin, 1845

Subphylum Secernentia: Order Rhabditida: Suborder Rhabditina: Family Rhabditidae (ref. ID; 1276)

Order Rhabditida (ref. ID; 6180)

Suborder Rhabditina: Family Rhabditidae (ref. ID; 3547)

Family Rhabditidae (ref. ID; 6182, 6740)

ref. ID; 1663

Stoma elongate, open, cylindrical; one anterior and one posterior ovary, or single anterior ovary; cuticle weakly annulated; a terrestrial family having several genera occasionally found in semiaquatic and aquatic habitats. Most common genus. (ref. ID; 1663)

ref. ID; 3547, 6691, 6859

Bacterial feeder. (ref. ID; 3547, 6691, 6859)
  1. Rhabditis anomala (ref. ID; 7805)
  2. Rhabditis armata Fuchs, 1931 (ref. ID; 7628)
  3. Rhabditis (Pellioditis) bengalensis (ref. ID; 6557)
  4. Rhabditis blumi (ref. ID; 7080)
  5. Rhabditis boettgeri Meyl, 1953
    See; Teratorhabditis boettgeri (ref. ID; 5941)
  6. Rhabditis brevispina Claus, 1863 (ref. ID; 2588)
  7. Rhabditis brought (ref. ID; 3547)
  8. Rhabditis (Pelodera) comandorica (ref. ID; 6557)
  9. Rhabditis curvicaudata (Schneider, 1866) (ref. ID; 7628), (Schneider, 1866) Oerley, 1880 (Dougherty, 1955) (ref. ID; 1749)
  10. Rhabditis dentifera Volk, 1950
    See; Teratorhabditis dentifera (ref. ID; 5941)
  11. Rhabditis (Cephaloboides) dimorpha Sudhaus, 1976 (ref. ID; 7628)
  12. Rhabditis dolichura Schneider, 1866 (ref. ID; 2588) reported author and year? (ref. ID; 3547)
  13. Rhabditis elongata Schneider, 1866 (ref. ID; 2588)
    See; Rhabditella axei
  14. Rhabditis filiformis Butschli, 1873 (ref. ID; 2588)
  15. Rhabditis glutinus Dujardin, 1845
    See; Panagrellus redivivus (ref. ID; 870)
  16. Rhabditis (Rhabditoides) inermiformis (ref. ID; 6557)
  17. Rhabditis (Pellioditis) littorea Sudhaus & Nimrich, 1988 (ref. ID; 6557 original paper)
  18. Rhabditis longicaudatus Bastian, 1865 (ref. ID; 2588)
  19. Rhabditis (Pellioditis) marina Bastian, 1865 (superspecies) (ref. ID; 6557)
  20. Rhabditis maupasi Seurat, 1919 (ref. ID; 7805)
    Syn; Rhabditis pellio Butschli, 1873 (ref. ID; 7805)
  21. Rhabditis mediterranea Sudhaus, 1974 (ref. ID; 6557)
  22. Rhabditis monhystera Butschli (ref. ID; 2588)
  23. Rhabditis muscicola Rahm, 1928 (ref. ID; 7628)
    Syn; Rhabditis muscicola var. brevicauda Rahm, 1929 (ref. ID; 7628); Rhabditis pseudoxycerca Goodey, 1929 (ref. ID; 7628)
  24. Rhabditis (Cephaloboides) nidrosiensis (ref. ID; 6557)
  25. Rhabditis (Cephaloboides) oxycerca (ref. ID; 1722)
  26. Rhabditis paraciliata Goodey, 1943 (ref. ID; 7628)
  27. Rhabditis pellio (Schneider) (ref. ID; 1724) or (Schneider) Butschli, 1873 (ref. ID; 7805)
  28. Rhabditis pelloides Butschli, 1873 (ref. ID; 2588)
  29. Rhabditis producta Schneider, 1866 (ref. ID; 2588)
  30. Rhabditis pseudoxycerca Goodey, 1929
    See; Rhabditis muscicola Rahm, 1928 (ref. ID; 7628)
  31. Rhabditis rovinjensis Sudhaus, 1974
    See; Teratorhabditis rovinjensis (ref. ID; 5941)
  32. Rhabditis (Crustorhabditis) scanica (ref. ID; 6557)
  33. Rhabditis schneideri Butschli, 1873
    See; Cheilobus quadrilabiatus (ref. ID; 2588)
  34. Rhabditis (Marispelodera) spiculigera (ref. ID; 6557)
  35. Rhabditis (Marispelodera) stasileonovi (Belogurov, 1977) n. comb. Sudhaus & Nimrich, 1988 (ref. ID; 6557 redescribed paper)
    Syn; Marispelodera stasileonovi Belogurov, 1977 (ref. ID; 6557)
  36. Rhabditis teres (ref. ID; 1749)
  37. Rhabditis terricola Dujardin, 1845 (ref. ID; 1749, 2588) reported author and year? (ref. ID; 3547)
  38. Rhabditis tokai (ref. ID; 1749)
  39. Rhabditis (Pellioditis) typica Stefanski, 1922 (ref. ID; 6557)
  40. Rhabditis (Cephaloboides) valida (ref. ID; 6557)
  41. Rhabditis verneti (Vernet, 1872) Maupas, 1900 (ref. ID; 7805)

Rhabditis (Pellioditis) littorea Sudhaus & Nimrich, 1988 (ref. ID; 6557 original paper)

Diagnosis

Rhabditis littorea is medium-sized, with the (plesiomorphic) characters of the stem species of the subgenus Pellioditis. These character states are as follows: posterior half of stoma ensheathed by pharyngeal collar, metarhabdions with tubercles, vulva median, bursa peloderan and open, 9 pairs of papillae present, 3 anterior to cloaca, Nos.5 and 8 terminating on outer surface of the velum, spicules separate, dagger-shaped. In this group, R. littorea is closely related to R. (P.) typica Stefanski, 1922 (seuse Sudhaus (1976), non sensu Andrassy (1984)) and the supposed superspecies R. (P.) marina Bastian, 1865, because of its distinct middle pharyngeal bulb and the arrangement in a (1 + 2/3 + 3) series of the bursal papillae. (ref. ID; 6557)

Descriptions

  • Adult: Body linear. Whitish, cuticle 0.9 µm thick, finely annulated, 10 annules corresponding to 7-11 µm; longitudinal striae indistict, composed of fine dots, as observed under high magnification. Lateral field, unstructured and inconspicuous, begins posteriorly from stoma; 7-12 µm wide. Cephalic diameter of female 11-13 µm, of male 8-12 µm; 6 lips closed, slightly protuberant, each with 2 small sensillare; oval aperture of amphids indistinct. Buccal cylinder 1.5-1.8 times as long as cephalic diameter, 3-4.5 µm wide, about 5-6 times longer than wide. Cheilorhabdions absent; wall of anterior part to pharyngeal collar (= prostoma) strengthened. Glottoid apparatus well developed, slightly anisoglottid; metarhabdions each with (probably two) warts. Pharyngeal collar enclosing 55-65% of buccal cylinder; pharynx rhabditoid, 7-9 times length of stoma. Median bulb width 22-27(25) µm in females and 15-20(18) µm in males (79-91% of diameter of terminal bulb). Width of terminal bulb 26-34(29) µm in females, 19-23(21) µm in males, provided with duplex haustrulum posterior from valve plates. Distance from anterior end of body to end of median swelling is 54-58% of pharynx length. Cervical gland distinct; duct and pore only rarely observed; pore situated at 83-116% of pharynx length; lateral duct in epidermis observed at least to level of posterior gonad flexure in female. (ref. ID; 6557)
  • Female: Gonads amphidelphic. Together comprising 51-62% of body length; posterior branch (on left side of intestine corresponding to 91-115% of anterior (on right side). Branches dorsally reflexed, anterior flexure spanning 40-53%, posterior flexure 21-38% of respective branch. Sphincter between oviduct and uterus, formed by 4 cells, about 72-115 µm from vulva. Sperm numerous in uterus between eggs. Each uterus with maximum of 4 eggs, up to the four-cell stage. Dimensions of ova 42-47(45)x22-31(27) µm. Two pseudocoelomocytes, each 10x13 µm, situated distally for much flexure of gonoduct. Vulva slit-like, transverse to body axis, and with slightly protruding lips; each lip with small sensilla. Vulvar region of fertilized females with small copulatory plug. Three rectal glands present. Rectum 18-31(25) µm long, anal body diameter 23-31(27) µm. Tail long and slender, 5-6 times anal body width. Phasmids incospicuous, situated at 21-28(24)% of tail length. Aberrant females with knot-like swellings of the tail near or at the tips. (ref. ID; 6557)
  • Male: Testis situated to right of intestine, occupying 59-68% of the body length; ventrally reflexed part 52-85(75) µm long, i.e., 15-19% of testis length. Two pseudocoelomocytes anterior from flexure and one posterior from posterior end of flexure barely visible; diameter of pseudocoelomocytes about 8 µm. Vas deferens without appendices. Sperm spherical; diameter about 5 µm. Bursa peloderan, open, with velum and its margin smooth, neverthless often with a terminal notch. Nine pairs of papillae, arranged (1 + 2/3 + 3): first papilla 25-50 µm anterior to cloacal opening, papillae 2 and 3 close together in front of cloaca, postcloacally two closed groups of 3 papillae, respectively. Papillae 5 and 8 opening on outer sides of velum, and remaining pairs incorporated in velum and extending to near bursal margin. In one male papilla No. 7, instead of No. 8, on the left-hand side only turned dorsal and directed outwards. In one male, papillae 2 and 3 fused on the right had side, with only their tips remaining separate, and papillae 5 and 6 with larger separation than usual. In one male, gap between papillae 4 and 5 larger on left hand side only. Opening of phasmids at base of conical tail tip. Anterior lip of cloaca with median papilla. Spicules of equal length, yellowish, separate, dagger-shaped, with pointed extremity slightly offset. Right spicule in one case only 89% length of left. Gubernaculum linear, shaped like a shoe horn, spanning 46-57% of spicule length. (ref. ID; 6557)

    Type locality and habitat

    Vancouver Island, near Tofino, Canada, algal deposits from the shore, October 1986. Living in decaying seaweed. (ref. ID; 6557)

    Type designations

    Holotype (female) Catalogue No.11004 and paratypes (males, females, immatures) Nos.11005, 11006 in the collection of the Museum fur Naturkunde der Humboldt-Universitat (Zoologische Museum) Berlin, German Democratic Republic; other paratypes containing males and females deposited at Biosystematics Research Centre, Ottawa, Canada; Laboratorium voor Nematologie, Landbouwhogeschool, Wageningen, Holland; and Biologische Bundesanstalt fur Land- und Forstwirtschaft (Institut fur Nematologie), Munster, Federal Republic of Germany. (ref. ID; 6557)

    Rhabditis (Pellioditis) marina Bastian, 1865 (superspecies) (ref. ID; 6557)

    Remarks

    Rhabditis marina seems to be a species complex, and is currently being studied in our laboratory. We support Andrassy's (1984) opinion that two species (R. marina Bastian, 1865 and Rhabditis mediterranea Sudhaus, 1974), or even more, may be involed. Males of the Vancouver Island population showed characteristics described for the typical R. marina by Sudhaus (1974). They had a regular pattern of fine scales on the bursa velum an stout spicules with slightly notched tips, but without a dorsal thorn. Cultures were established on agar plates with small pieces of potato added. (ref. ID; 6557)

    Rhabditis (Cephaloboides) oxycerca (ref. ID; 1722)

    Descriptions

    Saprozoic species. (ref. ID; 1722)

    Rhabditis (Marispelodera) stasileonovi (Belogurov, 1977) n. comb. Sudhaus & Nimrich, 1988 (ref. ID; 6557 redescribed paper)

    Synonym

    Marispelodera stasileonovi Belogurov, 1977 (ref. ID; 6557)

    Remarks

    This is the first record of the species since its discovery on Commander Islands (Bering, USSR) (Belogurov 1977). Rhabditis stasileonovi is unique among Rhabditis in the combination of posterior vulva and dome-shaped female tail without a spine. We observed only one female, which lived for about 14 days on an agar plate without producing any offspring. We therefore assume that the species is bisexual, and that the female had not been impregnated. (ref. ID; 6557)
  • Male: Male are not known. (ref. ID; 6557)