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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ironus

Ironus Bastian, 1865 (ref. ID; 3570, 7242)

Enoplida Filijev, 1929: Family Ironidae De Man, 1876 (ref. ID; 3570)

Order Enoplida: Family Ironidae (ref. ID; 6862)

Family Ironidae (ref. ID; 880, 6182, 6740, 7242)

ref. ID; 1663

Three large, hooklike teeth at anterior end of stoma; two ovaries, one anterior and one posterior to vulva. Esophagus cylindrical, without a basal bulb. Common species. (ref. ID; 1663)

ref. ID; 1795

Predator. (ref. ID; 1795)

ref. ID; 1923

Teeth at anterior end of stoma. Caudal glands absent. Aquatic. (ref. ID; 1923)

ref. ID; 3570

Type species

Ironus ignavus Bastian, 1865 (ref. ID; 3570)
  1. Ironus americanus Cobb, 1914 (ref. ID; 3570) or 1919 (ref. ID; 7242)
    Syn; Ironus truncatus Stefanski, 1916 (ref. ID; 3570)
  2. Ironus andamanensis Sukul, 1968 (ref. ID; 3570)
  3. Ironus andamanus (ref. ID; 7242)
  4. Ironus brevicaudatus (subsp.) Brakenhoff, 1914
    See; Ironus ignavus subsp. brevicaudatus (ref. ID; 3570), Ironus tenuicaudatus (ref. ID; 3570)
  5. Ironus colourus Steiner, 1919 (ref. ID; 3570) reported author and year? (ref. ID; 7242)
    Syn; Ironus ignavus subsp. colourus Steiner, 1919 (ref. ID; 3570)
  6. Ironus crassatus (ref. ID; 7242)
  7. Ironus dentifurcatus Argo & Heyns, 1972 (ref. ID; 1311) reported author and year? (ref. ID; 7242)
  8. Ironus elegans Colomba & Vinciguerra, 1979 (ref. ID; 1899, 7242)
  9. Ironus entzii (Daday, 1894)
    See; Ironus tenuicaudatus (ref. ID; 3570)
  10. Ironus ernsti Argo & Heyns, 1972 (ref. ID; 1899, 7242)
  11. Ironus filicauda (Daday, 1899)
    See; Ironus longicaudatus (ref. ID; 3570)
  12. Ironus filiformis Altherr, 1963
    See; Ironus helveticus (ref. ID; 3570)
  13. Ironus helveticus Daday, 1911 (ref. ID; 3570, 7242)
    Syn; Ironus filiformis Altherr, 1963 (ref. ID; 3570)
  14. Ironus ignavus Bastian, 1865 (ref. ID; 1861, 1899, 3570) reported author and year? (ref. ID; 7242)
    Syn; Ironus intermedius Stefanski, 1936 (ref. ID; 3570); Ironus longicollis Daday, 1899 (ref. ID; 3570); Ironus minor N.A. Cobb in M.V. Cobb, 1915 (ref. ID; 3570)
  15. Ironus indicus (ref. ID; 7242)
  16. Ironus intermedius Stefanski (ref. ID; 3570) reported year? (ref. ID; 1774)
    See; Ironus ignavus (ref. ID; 3570)
  17. Ironus lautus (ref. ID; 7242)
  18. Ironus longicauda (Cobb, 1893)
    See; Ironus longicaudatus (ref. ID; 3570)
  19. Ironus longicaudatus De Man, 1884 (ref. ID; 1861, 2592, 3570) reported author and year? (ref. ID; 7242)
    Syn; Aphanolaimus papillatus Daday, 1899 (ref. ID; 3570); Cephalonema longicauda Cobb, 1893 (ref. ID; 3570); Ironus filicauda Daday, 1899 (ref. ID; 3570)
  20. Ironus longicollis Daday, 1899
    See; Ironus ignavus (ref. ID; 3570)
  21. Ironus luci Andrassy, 1956 (ref. ID; 3570) reported author and year? (ref. ID; 7242)
  22. Ironus macramphis Stekhoven & Teunissen, 1938 (ref. ID; 3570), Stekhoven & Teunisson, 1938 (ref. ID; 7242)
  23. Ironus minor N.A. Cobb in M.V. Cobb, 1915
    See; Ironus ignavus (ref. ID; 3570)
  24. Ironus paludicola W. Schneider, 1937 (ref. ID; 3570) reported author and year? (ref. ID; 7242)
    Syn; Ironus ignavus subsp. paludicola W. Schneider, 1937 (Cobb, 1893) (ref. ID; 3570)
  25. Ironus papuanus Daday, 1899 (ref. ID; 3570)
  26. Ironus paramacramphis Altherr & Deboutteville, 1972 (ref. ID; 7242)
  27. Ironus rotundicaudatus Kreis, 1924 (ref. ID; 3570) reported author and year? (ref. ID; 7242)
  28. Ironus sphincterus Ebsary, 1985 (ref. ID; 1899, 7242 original paper)
  29. Ironus tenuicaudatus De Man, 1876 (ref. ID; 3570) reported author and year? (ref. ID; 7242)
    Syn; Ironus entzii Daday, 1894 (ref. ID; 3570); Ironus ignavus subsp. brevicaudatus Brakenhoff, 1914 (ref. ID; 3570)
  30. Ironus terranovus Ebsary, 1985 (ref. ID; 7242 original paper)
  31. Ironus truncatus Stefanski, 1916
    See; Ironus americanus (ref. ID; 3570)

Ironus dentifurcatus Argo & Heyns, 1972 (ref. ID; 1311) reported author and year? (ref. ID; 7242)

Descriptions

Fairly long nematodes with more or less cylindrical body. Body posture upon fixation either almost straight or slightly ventrally curved. Under the light microscope the cuticle appears to be smooth, but SEM photographs show very fine transverse striations. Also, SEM pictures show lateral body pores, the first situated about 3 µm posterior to the level of lip region constriction. Body contains large, rectangular crystalloid bodies. Six inner and six outer labial papillae plus four short cephalic setae are found on the lip region, the cephalic setae being situated immediately anterior to the constriction line that separates the lip region from the rest of the body. Head-on views as well as SEM pictures show that the lip region is hexagonal in shape, with fused lips and three liplets projecting anteriorly. Stoma well sclerotized, very long, and clearly composed of two parts, an anterior wider chamber followed by a more or less tubular, posterior part. The tubular part itself is wide anteriorly but becomes narrower posteriorly. Three strongly developed teeth are situated in the stoma chamber, two being ventrosublateral while the remaining one is dorsal in position. Transverse rows of denticles in the cheilstome visible under SEM. The dorsal tooth is bifurcated and it consists of two tips implemented on a common base. The tips are smaller than the ventrosublateral teeth. Amphid narrow, nearly a quarter of the lip region width, stirrup shaped, opening situated at the level of lip region constriction. Pharynx cylindrical, with its muscles starting on the dorsal side around the middle of the stoma, On the ventral side the pharyngeal muscles start at around two-thirds of the stoma. Nerve ring surrounds pharynx anterior to middle. Ventral gland highly granular and situated far posterior in the body while its duct reaches the lip region. Excretory pore 25 µm or about 3 times the lip region width behind anterior end. Cardia triangular, more than one-third of the corresponding body width, and with a sinuous lumen. Intestine with wide lumen. Rectum on and one-third anal body width long. Tail long, tapering rapidly in its anterior 15%, terminating in a filiform tip. Muscle layer in the tail region drastically reduced. Female reproductive system didelphic, amphidelphic with reflexed ovaries. Vagina slightly longer than one-third of the corresponding body width, and fairly muscular. Vulva a transverse slit, situated very anterior to middle of body. (ref. ID; 1311)
  • Male: Male not found. (ref. ID; 1311)
    The original description of the species by Argo & Heyns (1972) differ followed. (1) having rectangular crystalloid bodies, (2) a narrower amphidial fovea and aperture, (3) absence of longitudinal striae. (ref. ID; 1311)

    Measurements

    Body length 1556+/-108.6(1314-1719) µm, maximum body width 35+/-2.4(31-39) µm, pharyngeal length measured from the anterior end 255+/-13.4(231-277) µm, tail length 372+/-51.2(237-440) µm, anal body width 21+/-1.4(20-25) µm, lip region width 15+/-1.5(11-17) µm, stoma length 76+/-10.9(61-94) µm, stoma width at its widest tubular part 4+/-0.5(3-5) µm, length of anterior genital branch 186+/-73.6(100-383) µm, length of posterior genital branch 194+/-56.7(105-286) µm, vagina length 12+/-2.0(10-17) µm, amhidial fovea width 4+/-0.7(3-5) µm, nerve ring from the anterior end 120+/-6.7(108-128) µm, cardia width 14+/-2.2(10-17) µm, corresponding body width 32+/-1.6(30-35) µm, rectal length 28+/-1.3(27-31) µm. (ref. ID; 1311)

    Ironus ernsti Argo & Heyns, 1972 (ref. ID; 1899, 7242)

    Descriptions

    This species has a bifid dorsal tooth and inconspicuous nerve ring. Also, females are characterized by having longitudinal vulva and males with single, reflexed testis. Males have wider lip region and longer ventromedian supplement. (ref. ID; 1899)

    Ironus ignavus Bastian, 1865 (ref. ID; 1861, 1899, 3570) reported author and year? (ref. ID; 7242)

    Synonym

    Ironus intermedius Stefanski, 1936 (ref. ID; 3570); Ironus longicollis Daday, 1899 (ref. ID; 3570); Ironus minor N.A. Cobb in M.V. Cobb, 1915 (ref. ID; 3570)

    Diagnosis

    In being small and didelphic, in having stoma less than 90.0 µm, 'c' less than 20.0, 'c`' greater than 5.0, a vulva situated behind mid-body, and in lacking a sclerotized, refractive sphincter, this specimens come close to two species viz. I. americanus Cobb, 1914 and I. ignavus Bastian, 1865. These two species are similar but, they can be differentiated from each other by their respective values for the ratios 'a' and 'c'. As originally described I. americanus has higher value for the ratio 'a' and lower value for the ratio 'c' compared to I. ignavus (a=34.0-37.0, 40.0-55.0, c=13.0-15.0, 6.0-10.0, respectively in I. americanus and I. ignavus) (Bastian, 1865; Cobb, 1914). Eyualem (1997) calculation of the ratio 'c`' from Cobb's formula for the species gives a value of 5.7, while from Bastian's original drawings it is about 10.0 for I. ignavus. Although the values for the ratios 'c' and 'c`' could be useful to differentiate the two species, the usefulness of the reported slight difference in the value for the ratio 'a', as seen in the light of the variation of the body width in the genus based on reproductive maturity, is questionable. For instance, Tsalolikhin (1987) has reported a range 38.0-63.0 for the ratio 'a' in I. ignavus. (ref. ID; 1899)

    Descriptions

  • Female: Body posture after fixation slightly (one specimen) to strongly curved dorsad (two specimens). Maximum body width between base of pharynx and halfway the distance between vulva and anus. Cuticle smooth; lateral body pores absent. Metanemes inconspicuous in most, two orthometanemes seen only in one specimen. Crystalloid bodies distributed in all parts of the body; probably in the pseudocoelom as well as in the musculature; their size ranges from 1.0-10.0 µm wide and 1.0-12.0 µm long, and their shape varies from spindle-shaped to rectangular. An inner circle of six outer labial papillae and an outer circle of four cephalic setae on the lip region. Inner labial sensilla inconspicuous, probably papilloid and small. Outer labial papillae on the anterior side of lip region. Cephalic setae 22.7-31.8% lip region width, situated on the sides of the lip region, at the level immediately anterior to the weak constriction-line between the slightly but detectably bulging lip region and the rest of the body. Cheilostome short (2.0-2.5 µm long) and narrow. Rest of stoma well sclerotized, very long, and composed of two parts, an anterior wider chamber followed by a more or less cylindrical, posterior part. Cylindrical part gradually narrows posteriorly. Three anteriorly curved and strongly developed teeth, one simple dorsal and two ventrosublateral, in the wider part of the stoma. Ventrosublateral teeth slightly larger than dorsal one. Three pharyngeal gland openings in the stoma: two anteriorly situated (about 9.0 µm from anterior body end) ventrosublateral gland openings and more posteriorly (about 35.0 µm from anterior body end) one dorsal gland opening. Amphids sirrup shaped, opening situated at the level of lip region constriction, about two-fifths of corresponding body width wide. Pharynx cylindrical for most of its length somewhat constricted at the level of the nerve ring. Where exactly the pharynx musculature starts is not evident, but, muscles become unambiguously conspicuous on the dorsal side around the middle of the stoma. On the ventral side, the pharyngeal muscles become conspicuous about 10.0 µm anterior to the end of the stoma. Nerve ring surrounds pharynx at about a third to two-fifths of pharyngeal length. Excretory pore and ventral gland not seen. Cardia triangular, slightly more than one-third of the corresponding body width. Intestine with distinct microvilli, its cells filled with brown granules, leading to a 25.0-27.0 µm long rectum. Female reproductive system didelphic, amphidelphic with reflexed ovaries, position of reproductive system with respect to intestine variable. Uterus separated from remainder of gonoduct by a weakly muscular sphincter. Vagina muscular, about half corresponding body width long. Vulva a transverse slit, situated slightly posterior to mid-body. Eggs 5-8 times longer than wide, 20.0-25.0 µm x 127-160 µm. Tail gradually tapering to a fine sharp tip; about 6 rectal lengths long. (ref. ID; 1899)
  • Male: Not found. (ref. ID; 1899)

    Ironus sphincterus Ebsary, 1985 (ref. ID; 1899, 7242 original paper)

    Diagnosis

    In having a well sclerotized and refractive sphincter, this specimens come close to two species in the genus with a similar character viz. I. elegans Colomba & Vinciguerra, 1979, I. ernsti Argo & Heyns, 1972 (ref. ID; 1899)

    Differential diagnosis

    Ironus sphincterus n. sp. is most similar to I. helveticus Daday, 1911, I. elegans Colomba and Vinciguerra, 1979, and I. ernsti Argo and Heys, 1972. The new species differs from I. helveticus by having a highly refractive sphincter between each oviduct and uterus, a greater heat width (16-17 µm vs. 12-13 µm), a smaller a value (40-52 vs. 75-95), and a larger c value (16-20 vs. 12-15). Ironus sphincterus, I. elegans, and I. ernsti have prominent, refractive oviduct sphincters. The new species differs from I. elegans by the greater a value (40-52 vs. 36), the greater c value (16-20 vs. 9), the smaller c' value (4.9-5.8 vs. 8), and the differently shaped tail (elongate conoid versus conoid then spicate). The new species differs from I. ernsti by the much shorter and differently shaped tail (less than 201 µm and elongate conoid vs. up to 710 µm and conoid, tapering to filiform terminal portion), the longer body (more than 2.7 mm vs. less than 2.5 mm), the more anterior vulva (48-54% vs. 54-63%), and the differently positioned vulva (transverse versus longitudinal). (ref. ID; 7242)

    Descriptions

    Female: Body posture after fixation more or less straight (1 specimen) or slightly curved ventrad (3 specimens). Maximum body width between base of pharynx and half distance between vulva and anus. Cuticle smooth, with faint intra-cuticular canals (lateral body pores?) that were seen as faint lines reaching the outer layer of the cuticle from inside, mostly conspicuous behind mid-body; external opening to seen. Metanemes inconspicuous in most, 2 orthometanemes seen only in one specimen. Dense crystalloid bodies distributed in all parts of the body, most concentrated between base of pharynx and anus, situated probably in the pseudocoelom as well as in the musculature. Size and shape of crystalloid bodies variable: 1.0-2.0 µm wide and 2.0-75.0 µm long. An inner circle of six outer labial papillae and an outer circle of four cephalic setae on the lip region. Inner labial sensilla inconspicuous, probably papilloid and small. Outer labial papillae on the anterior side of lip region. Cephalic setae 27.8-32.1% lip region width, situated on the sides of the lip region at the level immediately anterior to the weak constriction-line between the conspicuously bulging lip region and the rest of body. Cheilostome short (2.0-3.0 µm long) and narrow. Rest of stoma well sclerotized, very long, and composed of two parts, an anterior wider chamber followed by a more or less cylindrical, posterior part. Three almost equally developed anteriorly curved teeth, one dorsal and two ventrosublateral in the wider part of the stoma. Three pharyngeal gland openings in the stoma, two anteriorly situated (about 15.0 µm from anterior body end) ventrosublateral gland openings and one more posteriorly (about 54.0 µm from anterior body end) situated dorsal gland opening. Amphids stirrup shaped, opening situated at the level of lip region constriction, slightly more than half corresponding body width wide. Pharynx cylindrical for most of its length with a narrower part at the level of the nerve ring. Where exactly the pharynx musculature starts was not evident, but muscles are unambiguously conspicuous on the dorsal side around the middle of the stoma. Pharyngeal musculature on the ventral side becomes conspicuous about 10.0 µm anterior to the end of the stoma. Nerve ring surrounds pharynx at about a third of pharyngeal length. Excretory pore seen in one specimen, situated 47.0 µm from anterior body end. Ventral gland not seen. Cardia triangular, one-third to two-fifths of corresponding body width. Cells of the intestinal wall filled with brown granules. Intestine leading to 38.0-47.0 µm long rectum. Female reproductive system didelphic, amphidelphic with reflexed ovaries, position with respect to intestine variable. Spermatheca well defined, in some fully packed with spermatozoa. Uterus separated from gonoduct by strongly muscled, well scerotized and refractile sphincter. In female without egg, sphincter situated 80-110 µm from vulva. Vagina muscular; 44.1-50.0% corresponding body width long. Vulva a transverse slit, situated slightly posterior to mid-body. Eggs 3.3-4.2 times longer than wide (147-167 µm x 40.0-45.0 µm). Tail more or less elongate-conoid, drastically narrowing 65.0-75.0 µm from anus; gradually tapering more posteriorly, ending in a fine sharp tip; about 5.0 rectal lengths long. (ref. ID; 1899)

    Body slender, slightly curved ventrally. Cuticle smooth. Head 16-17 µm wide, flattened, set off from body by a constriction. Head setae 4-5 µm long. Amphids stirrup shaped 8-10 µm wide, and 50-60% of head width. Stoma base 98-105 µm from head apex, stoma width 5 µm. Anterior portion of stoma smooth becoming finely transversely striated about 35 µm posterior to head. Dorsal esophageal gland orifice at 48-50% of stoma length. Onchia strongly curved, pointed, 6-7 µm along longitudinal axis. Esophago-intestinal valve hemispherical. Vulva transverse, ovaries paired, opposed, reflexed. A conspicuous, highly refractive, funnel-shaped sphincter separates the oviduct and uterus in each ovary. Rectum 1.6-1.8 anal body widths long, set off from intestine by a conspicuous sphincter. Tail 175(158-201) µm long, elongate conoid tapering to a finely rounded tip. Crystalloids very numerous, variable in size and shape. (ref. ID; 7242)
  • Males: Unknown. (ref. ID; 7242)

    Type habitat and locality

    Collected by the Quebec Ministry of the Environment, October 1982 from St. Lawrence River bottom samples at Montreal, P.Q. (ref. ID; 7242)

    Type deposition

    Holotype female mounted on type slide No.279 and deposited in the Canadian National Collection of Nematodes, Ottawa. Paratypes of slides 279a-279g and deposited as above. (ref. ID; 7242)

    Measurements

  • Holotype (female): L=3.08 mm, a=43, b=5.2, c=17.8, c'=5.1, V=50. (ref. ID; 7242)
  • Paratypes (10 females): L=3.2(2.76-3.48) mm, a=46(40-52), b=5.7(5.2-6.6), c=18.5(16.3-20), c'=5.3(4.9-5.8), V=51(48-54). (ref. ID; 7242)

    Ironus terranovus Ebsary, 1985 (ref. ID; 7242 original paper)

    Differential diagnosis

    Ironus terranovus n. sp. is most similar to I. macramphis Schuurmans Stekhoven and Teunisson, 1938 and I. paramacramphis Altherr and Deboutteville, 1972. The new species differs from I. macramphis by a longer stoma (102-110 µm vs. 90-100 µm) with the posterior two thirds finely transversely striated (strations absent in I. macramphis according to Altherr and Deboutteville (1972)). The new species also differs by the amphid width/head width percentage of 35 vs. 50, the smaller c values (3.0-3.7 vs. 4.0-5.6), and a more anterior vulva (37-40 vs. 41-46%). The new species differs from I. paramacramphis by being shorter (2.9-3.37 mm vs. 3.4-3.8 mm) and by having a narrower head (15-16 µm vs. 22 µm), more anterior vulva (37-40% vs. 41-43%), and a smaller c values (3.0-3.7 vs. 3.9-5). (ref. ID; 7242)

    Descriptions

    Female: Body slender, slightly curved ventrally. Cuticles smooth. Head 17-18 µm wide, flattened, set off from body by a constriction. Head setae 3-4 µm long. Amphids funnel shaped, 6-7 µm wide and about one-third head width. Stoma base 106(102-110) µm from head apex. Dorsal esophageal gland orifice 66(62-70) µm or 61(59-65)% from head. Anterior portion of stoma with three, 4-5 µm long, curved, pointed onchia. Stoma with fine transverse striae beginning about 35-40 µm posterior to head. Esophago-intestinal valve hemispherical. Vulva transverse. Vagina weakly developed, ovaries opposed, reflexed. Rectum 1.4-1.6 anal body widths long, set off from intestine by a distinct sphincter. Tail 921(777-1058) µm, conoid, tapering through a finely drawn out filiform portion. (ref. ID; 7242)

    Type habitat and locality

    Collected by the author, July 1981, from a bottom sample taken from a small stream at Cape Spear, Nfld. (ref. ID; 7242)

    Type deposition

    Holotype female mounted on slide No.280 and deposited in the Canadian National Collection of Nematodes, Ottawa. Paratypes mounted on slides 280 and 280a and deposited as above. (ref. ID; 7242)

    Measurements

  • Holotype (female): L=3.3 mm, a=51, b=6.9, c=3.3, c'=29, V=38. (ref. ID; 7242)
  • Paratypes (9 females): L=3.14(2.9-3.37), a=48(47-51), b=6.4(6-6.9), c=3.5(3.0-3.7), c'=27(24-30), V=39(37-40). (ref. ID; 7242)