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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ditylenchus

Ditylenchus Filipjev, 1934 (ref. ID; ?) or 1936 (ref. ID; 7210)

Suborder Tylenchina: Family Anguinidae (ref. ID; 3547)

Family Anguinidae (ref. ID; 6182, 6740)

ref. ID; 1923

Female with 1 ovary. (A large genus, about 30 species, sometimes aquatic, usually terrestrial). (ref. ID; 1923)

ref. ID; 6859

Hyphal feeder. (ref. ID; 6859)

ref. ID; 7210

In the most recent revisionary study of the genus Ditylenchus, Fortuner (1982) identified seven relatively stable characters which permit with facility the separation of species and species groups of close affinities. Of the species having a stylet length of less than 10 µm, a pointed tail terminus, six incisures, a short postuterine sac, a V value of 77-83, an short bursa, D. valveus is most closely related to D. tenuidens Gritzenko, 1971. These species appear to differ only in spicule length (17-20 µm versus 15 µm for D. tenuidens) and in length of the female esophagus (less than 140 µm in D. valveus versus 155 µm). (ref. ID; 7210)
  1. Ditylenchus equalis Heyns, 1964 (ref. ID; 7210)
  2. Ditylenchus destructor (ref. ID; 3547)
  3. Ditylenchus dipsaci (Kuhn) Filipjev (ref. ID; 6692) reported author and year? (ref. ID; 1751, 3547)
  4. Ditylenchus filimus Anderson, 1983 (ref. ID; 7210 original paper)
  5. Ditylenchus intermedius (de Man, 1880) (ref. ID; 2588)
  6. Ditylenchus major (Fuchs, 1914) (ref. ID; 2588)
  7. Ditylenchus microdens Thorne & Malek, 1968 (ref. ID; 7210)
  8. Ditylenchus myceliophagus (ref. ID; 3547)
  9. Ditylenchus nortoni (Elmiligy, 1971) Bello & Geraert, 1972 (ref. ID; 7210)
  10. Ditylenchus sibiricus German, 1969 (ref. ID; 7210)
  11. Ditylenchus tenuidens Gritzenko, 1971 (ref. ID; 7210)
  12. Ditylenchus triformis (ref. ID; 7621)
  13. Ditylenchus valveus Thorne & Malek, 1968 (ref. ID; 7210 emended description paper)

Ditylenchus dipsaci (Kuhn) Filipjev (ref. ID; 6692) reported author and year? (ref. ID; 1751, 3547)

Descriptions

Plant-parasites. (ref. ID; 6692)

Ditylenchus filimus Anderson, 1983 (ref. ID; 7210 original paper)

Diagnosis

A short stylet and postuterine sac, 4 incisures, pointed or filamentous tail terminus, vulva at more than 77% of body length, and esophageal bulb never overlapping intestine related D. filimus n. sp. most closely the D. equalis Heyns, 1964, D. microdens Thorne & Malek, 1968, D. nortoni (Elmiligy, 1971) Bello & Geraert, 1972, and D. sibiricus German, 1969. From these species D. filimus is distinctive by its long spicules (29 µm versus no more than 25 µm) and its tail often ending in a filamentous process. In addition, D. equalis differs from D. filimus by having the nerve ring near midisthmus (based on illustration), and a vulva to anus distance equal to, or slightly less than, length of tail. Ditylenchus microdens differs by having the nerve ring and excretory pore at midisthmus, a shorter tail (illustrated as less than 50 µm) that is less than vulva to anus distance. Ditylenchus nortoni differs from D. filimus slitlike amphids at base of lip region, excretory pore, nerve ring and deirid near midisthmus, and shorter bursa (illustrated as enveloping about 30% of tail). Ditylenchus sibiricus has a longer tail, 100 µm versus less than 80 µm, and a shorter gubernaculum, 4 µm versus 7 µm. (ref. ID; 7210)

Descriptions

  • Female: Body usually curved ventrally, sometimes nearly straight, robust, width at midbody 21-33 µm (25 µm, SD 3.4), body annule width 1-2 µm. Lateral field 4-6 µm wide, one sixth of body diameter, with 4 equally spaced incisures. Head low, with 1 or 2 fine basal annules, continuous with body. Amphids indistinct, observed on head apex when marked by amphidial secretions. Basal ring of head skeleton less than 2 µm deep. Stylet knobs rounded, about 2 µm in diameter. Dorsal esophageal gland duct about 2 µm posterior of stylet. Esophagus 88-105 µm (99 µm, SD 4.6) long, from head to metacorpal valve 38-47 µm (43 µm, SD 2.5), and from valve to base of esophagus 50-60 µm (56 µm, SD 3.6). Metacorpus fusiform, 8-9 µm wide, occupying less than half of corresponding body width. Metachorpal valve weakly cuticularized or indistinct in processed specimens, well cuticularized and conspicuous in living specimens. Basal esophageal bulb pyriform, length 16-21 µm (19 µm), width 8-10 µm (9 µm), without intestinal overlap. Nerve ring at base of isthmus. Excretory pore 89-106 µm (98 µm, SD 4.6) posterior to head end, ranging in levels from 11 µm anterior to base of esophagus in half the specimens, to 7 µm posterior. Excretory duct strongly cuticularized. Hemizonid usually conspicuous, immediately anterior to excretory pore. Deirid 6-13 µm (9 µm) posterior to excretory pore. Ovary outstretched, with one to three flexures in six specimens, extending to esophagus in two specimens. Oocytes in single row. Vulval lips protuberant. Postuterine sac short, 13-28 µm (16 µm, SD 2) long, 0.5-0.9(0.7) of body width at vulva, typically spheroid, never collapsed. Vulva to anus distance 43-56 µm (48 µm, SD 4). Tail 62-78 µm (72 µm, SD 4.6) long, 1.4-1.8(1.5) times vulva to anus distance. Tail conoid attenuated, terminus sharply pointed or ending in a filament 1.4-6.2 µm (3.9 µm) long in 78% of specimens. (ref. ID; 7210)
  • Male: Similar to female in general body characteristics. Esophagus 107 µm long, 42 µm from head to metacorpal valve, from valve to base of esophagus 65 µm. Excretory pore 91 µm posterior to head end. Bursa enveloping 61% of tail, margin crenate. Tail ending in a filamentous process. (ref. ID; 7210)

    Type locality

    Collected from beet pulp amended mushroom compost, Assiniboine Mushroom Inc., Oakville, Manitoba. Host unknown. (ref. ID; 7210)

    Type designations

    Deposited in the Canadian National Collection of Nematodes, Ottawa. (ref. ID; 7210)
  • Holotype (female): Type slide No.274.
  • Paratype (male): Type slide No.274a.
  • Paratypes (17 females): Type slide Nos.274b-274g.

    Measurements

  • Holotype (female): L=707 µm, a=32, b=7.0, c=9.8, c'=5.8, V=83, Ov=62%. Stylet length 8 µm. (ref. ID; 7210)
  • Paratype (17 females): L=619-788 µm (718 µm, SD 46), a=24-31(29, SD 2.7), b=6.3-8.3(7.3, SD 0.5), c=9.4-11.2(10.0, SD 0.5), c'=4.3-6.4(5.2, SD 0.7); V=83-85(84, SD 1), Ov=60-69% (64%, SD 2.8). Stylet length 7-9 µm (8 µm). (ref. ID; 7210)
  • Pataype (male): L=684 µm, a=31, b=6.1, c=10.1, c'=3.8. Stylet length 8 µm. Spicule length 29 µm. Gubernaculum length 7 µm. (ref. ID; 7210)

    Ditylenchus valveus Thorne & Malek, 1968 (ref. ID; 7210 emended description paper)

    Descriptions

  • Paratype female: Body with slight ventral curvature, uniformly thin, width at midbody 16-22 µm, body annules about 1.5 µm wide. Lateral field about 6 µm wide, at least a third of body width, with 6 incisures. Head low, rounded, with 1 or 2 basal annules, continuous with body. Basal ring of head skeleton well developed, more than 2 µm deep. Stylet knobs rounded, minute, about 2 µm or less in diameter. Dorsal esophageal gland duct about 2 µm posterior to stylet. Esophagus 116-139 µm long, from head to metacorpal valve 47-65 µm, from valve to base of esophagus 69-84 µm. Metacorpus fusiform, width 6-8 µm, basal esophageal bulb pyriform, length 21-25 µm, width 9-12 µm, its lumen axial, shifted slightly ventrad in one specimen. Nerve ring near midisthmus. Excretory pore 97-108 µm posterior to head end, located anterior to basal bulb. Hemizonid large, indistinct in one specimen, immediately anterior to excretory pore. Deirid 5-12 µm posterior of excretory pore. Ovary outstretched, extending to near base of esophagus in one specimen, oocytes in a single row. Vulva lips protuberant. Postuterine sac short, 23-36 µm long, 1.0-1.3 times body width at vulva. Vulva to anus distance 79-91 µm. Tail length 59-88 µm, 0.7-1.0 times vulva to anus distance. Tail elongate conoid, slightly expanded near middle in two specimens, tail terminus abruptly tapering to a narrowly rounded point. (ref. ID; 7210)
  • Male paratypes: Similar to female in general body characteristics. Excretory pore 91, 108 µm posterior to head end, hemizonid 2 or 3 annules anterior. Testis reflexed 34% of its length in larger specimen, outstretched in smaller. (ref. ID; 7210)

    Remarks

    Thorne and Malek (1968) reported that the ovary in old females of D. valveus may be reflexed once or twice and extend anteriorly as far as the metacorpus. As this degree of ovarial development was not observed in the paratypes, these authors apparently based their description, in part, on specimens from other than the type locality. Other disparities in the original description were a stylet length of 12 µm (illustrated at about 8 µm), and an (a) value of 36 as compared with 38-44 in the paratypes. The far ventral position of the esophageal basal bulb lumen reported as a character of the species was either median in the paratypes and Canadian specimens or, at most, shifted slightly ventrad. Canadian specimens of D. valveus differ from the paratypes by the generally longer female tail of 88-89(92) µm versus 59-88(79) µm, smaller c values of 8.4-10.9 versus 9.4-12.0, and longer spicules of 19-20 µm versus 17-18 µm. Tail shape of the Canadian specimens also is more variable, with some specimens, by contrast to regularly conoid, having tails which taper more rapidly in the posterior part, and with more sharply pointed tail termini. For the present these differences are not judged to be of diagnostic importance. (ref. ID; 7210)

    Measurements

    [After Thorne & Malek, 1968]
  • Female: L=900 µm; a=36; b=7.4; c=12; V=81. Stylet length 12 µm.
  • Male: L=800 µm; a=34; b=6.9; c=11; T=61.
  • Paratypes (3 females, 2 males): Female: L=707, 795, 831 µm; a=44, 40, 38; b=5.7, 5.7, 6.1; c= 12.0, 12.0, 9.4; c'= 5.6, 5.3, 5.9; V=80, 81, 79. Stylet length 9, 8, 8 µm. Male: L=714, 860 µm; a=42, 43; b=5.8, 6.0; c=8.2, 9.7; c'=7.0, 5.8; T=52, 60. Stylet length 8, 8 µm. Spicule length 17, 18 µm. Gubernaculum length 6.5 µm. (ref. ID; 7210)

    [Canadian specimens (6 females, 3 males)]
  • Female: L=736-1088(883) µm; a=37-45(42); b=5.3-8.9(7.3); c=8.4-10.9(9.6); c'=5.8-8.8(7.5); V=80-82(81); Ov=49-71(58). Stylet length 7-9(8) µm.
  • Male: L=755-850(792) µm; a=37-43(40); b=.5-7.3(6.9); c=8.7-9.1(8.9); c'=6.5-6.8(6.6); T=37-43(40). Stylet length 9 µm. Spicule length 19-20 µm. Gubernaculum length 5.6 µm. (ref. ID; 7210)