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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Chronogaster

Chronogaster Cobb, 1913 (ref. ID; 3571)

Araeolaimida De Coninck & Stekhoven, 1933: Family Leptolaimidae Orley, 1880: Subfamily Leptolaiminae Orley, 1880 (ref. ID; 3571)

Order Chromadorida: Family Chronogasteridae (ref. ID; 6862)

Order Chromadorida (ref. ID; 6180)

Family Plectidae (ref. ID; 6182)

ref. ID; 1663

Cephalic setae present; esophagus uniformly cylindrical anterior to basal bulb. Body slender and tapering very gradually anteriorly and posteriorly. (ref. ID; 1663)

ref. ID; 1795

Bacterial feeder. (ref. ID; 1795)

ref. ID; 1923

Stoma short and conoid; esophagus greatly elongated, esophago-intestinal valve elongated; 4 cephalic setae; preanal supplements tuboid. Aquatic. (ref. ID; 1923)

ref. ID; 3571

Type species

Chronogaster gracilis Cobb, 1913 (ref. ID; 3571)
  1. Chronogaster alata Gerlach, 1956 (ref. ID; 3571)
  2. Chronogaster andrassyi Loof & Jairajpuri, 1965 (ref. ID; 3571)
  3. Chronogaster boettgeri Kischke, 1956 (ref. ID; 3571)
  4. Chronogaster brasiliensis Meyl, 1957 (ref. ID; 3571)
  5. Chronogaster cameroonensis Heys & Coomans, 1984 (ref. ID; 1311)
  6. Chronogaster daoi Loof, 1964 (ref. ID; 3571)
  7. Chronogaster gracilis Cobb, 1913 (ref. ID; 3571) reported author and year? (ref. ID; 1923)
    See; Chronogaster longicollis (ref. ID; 3571)
  8. Chronogaster longicollis (Daday, 1899) Andrassy, 1958 (ref. ID; 3571)
    Syn; Cephalobus longicollis Daday, 1899 (ref. ID; 3571); Chronogaster gracilis Cobb, 1913 (ref. ID; 3571)
  9. Chronogaster magnifica Andrassy, 1956 (ref. ID; 3571)
  10. Chronogaster subtilis Andrassy, 1958 (ref. ID; 3571)
  11. Chronogaster tenuis Loof & Jairajpuri, 1965 (ref. ID; 3571)
  12. Chronogaster typicus (De Man, 1921) De Coninck, 1935 (ref. ID; 881, 1795, 3571)
    Syn; Walcherenia typica De Man, 1921 (ref. ID; 3571)

Chronogaster cameroonensis Heys & Coomans, 1984 (ref. ID; 1311)

Descriptions

Shape variable upon fixation, from open 'C'-shaped to completely coiled. Cuticle clearly annulated. Widest annuli situated between end of pharynx and mid-body, but annulus width decreases towards both ends. No lateral line. Lateral body pores present, SEM pictures show the pores to occur between annuli. A total of 5-7 vacuolar lateral glandular bodies, mainly situated between cardia and anus are also present. Many crystalloid bodies present, 1-2 µm x 2-4 µm, variously shaped: oval, elongate-ovoid, rectangular or sharply tapering on both sides; occurring throughout the body. Unstriated lip-region wider than long; with four cylindroid cephalic setae, one lip region width long. Lips show triradiate pattern when the mouth is slightly open, but this pattern disappears when the mouth is slightly open, but this pattern disappears when the mouth is closed. Amphid stirrup-shaped, aperture 3.3 µm (3-4 µm) wide i.e. half the corresponding body width and situated between the second and third annulus from the anterior end. SEM pictures show the presence of two notches that project from the posterior border of the amphidial fovea towards the centre of the fovea. Stoma cylindrical, 2x7 µm (6-8 µm). Radial tubules originating 15 µm (12-17 µm) behind the end of the stoma. Nerve ring anterior to middle of pharynx. Pharynx cylindrical for most of its length, terminating in an oval-shaped bulb. Basal bulb with longitudinal rows of seven denticles in its anterior half. Post-bulbal extension and cardia nearly as long as and about half as long as basal bulb, respectively. Cardia only in some specimens clearly separated from post-bulbal extension. Rectum one and one half anal body width long. Excretory pore seen only in two specimens, and situated behind nerve ring. Unlike the body pores, the excretory pore is situated in the middle of an annulus. Tail tapering anteriorly but more cylindroid posteriorly; it terminates in a 1.5 µm long dorsal mucro. Female reproductive system prodelphic, monodelphic, ovary reflexed, situated on the right side of the intestine. Post-vulval uterine sac one and one half times vaginal length. Vulva small, anterior to mid-body, appearing pore-like on SEM pictures. (ref. ID; 1311)
  • Eggs: 90x17 µm. (ref. ID; 1311)
  • Male: Not found. (ref. ID; 1311)

    Measurements

    Body length 938+/-65.8(801-1038) µm, maximum body width 18+/-2.3(15-23) µm, pharyngeal length measured from the anterior end 196+/-13.6(175-219) µm, tail length 219+/-29.5(167-268) µm, anal body width 11+/-0.7(9-11) µm, unstriated lip region width 7+/-0.7(6-8) µm, unstriated lip region height 5+/-0.9(4-7) µm, cephalic seta length 6+/-0.7(5-7), stoma length 6+/-0.7(6-8) µm, distance from buccal capsule to radial tubules 15+/-1.4(12-17) µm, basal bulb length 21+/-1.4(19-24) µm, post-bulbal extension length 24+/-6(14-31) µm, post-vulval uterine sac length 6+/-1.9(4-9) µm, vagina length 4+/-0.8 (3-8) µm, amphid width 3+/-0.5(3-4) µm, corresponding body width 7+/-0.4(7-8) µm, nerve ring from the anterior end 80+/-4.5(72-87) µm, rectal length 16+/-1.7(13-19) µm, annulus width at lip region 1.4+/-0.2(1-2) µm, annulus width at pharyngeal 2.3+/-0.2(2-3) µm, annulus width at mid body 2.0+/-0.2 µm, annulus width at anus 1.5+/-0.2(1-2) µm. (ref. ID; 1311)