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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Paratylenchus

Paratylenchus Micoletsky, 1922 (ref. ID; 5916) or Micoletzky, 1922 (ref. ID; ?)

Family Paratylechidae (ref. ID; 5916)

Family Tylenchulidae (ref. ID; 6168, 6182)

Subfamily Paratylenchinae (ref. ID; 7195)

ref. ID; 1923

A large genus, primarily terrestrial. (ref. ID; 1923)

ref. ID; 6691, 6859

Plant parasite. (ref. ID; 6691, 6859)
  1. Paratylenchus aciculus Brown, 1959 (ref. ID; 7195)
  2. Paratylenchus aculentus Brown, 1959 (ref. ID; 7195)
  3. Paratylenchus audriellus Brown, 1959 (ref. ID; 7195)
  4. Paratylenchus brevihastus Wu, 1962 (ref. ID; 7195)
  5. Paratylenchus hamatus Thorne & Allen, 1950 (ref. ID; 7195)
  6. Paratylenchus macrophallus (de Man, 1880) (ref. ID; 2588)
  7. Paratylenchus neoprojectus Wu & Hawn, 1975 (ref. ID; 5916 original paper, 7195)
  8. Paratylenchus projectus Jenkins, 1956 (ref. ID; 5916, 7195 redescribed paper)
  9. Paratylenchus robustus Wu, 1974 (ref. ID; 7195)
  10. Paratylenchus tateae Wu & Townshend, 1973 (ref. ID; 7195)
  11. Paratylenchus tenuicaudatus Wu, 1961 (ref. ID; 7195)

Paratylenchus neoprojectus Wu & Hawn, 1975 (ref. ID; 5916 original paper, 7195)

Diagnosis

Paratylenchus neoprojectus n. sp. is closely related to P. projectus. Its differs from the latter in having a longer spear, 28 to 31 µm long, a more posterior position of the excretory pore, usually at the level of basal esophageal bulb, and the head region is usually rounded. The spear of P. projectus is 24 to 28 µm long, excretory pore is usually at the level of isthmus and the sides of the head region usually straight and with a truncate front. (ref. ID; 5916)

Descriptions

Female: Body posture of heat-killed specimen bent ventrally. Head region generally rounded or broadly rounded, sometime faintly truncate front. Body annulation fine, about 1 µm wide. Lateral field about 3 µm wide with four faintly visible incisures. Hemizonid consists of two annules. Deirids present at the level of excretory pore. Location of the excretory pore usually at the level of basal esophageal bulb and frequently near the base of the basal esophageal bulb, ranging from 72 to 88 µm from anterior end. Spear slender, 28 to 31 µm long (100 spears measured), junction between two portions weak. Spear knob 3 µm across. Esophagus 82 to 94 µm long. Dorsal gland orifice about 6 µm posterior to the base of spear knob. Cardia present. Ovary well-developed, oocytes in single row, except in the region of multiplication. In mature females, tip of ovary usually reaches from the level of the basal esophageal bulb to 53 µm posterior to the basal esophageal bulb, in some specimens it reaches to the level of the median esophageal bulb. Posterior uternie branch present, comprised of 2 or 3 rudimentary ovarian cells, which are more clearly shown in young females as other cellular structures at the vulva region are less complicated. Crustaformecia well-developed, the columnar arrangement of the cellular structures is usually not clearly displayed. In a mature young female the crustaformeria has five columns, each column with four cells. Spermagonium present. Egg in uterus about 42x13 µm. Anus inconspicuous. Tail length 23 to 27 µm, 2.3 to 3.0 times body width at anal region. Tail terminus usually conically rounded, in some cases broadly or narrowly rounded. Vulva-anus distance 29 to 44 µm. (ref. ID; 5916)

Type locality

Collection No.6533, soil around alfalfa (Medicago sativa L.), collected from Breton, Alberta, June 1971. (ref. ID; 5916)

Type specimens

Holotype female type No.221, and 75 paratype females were reared from a single larva from collection No.6533. All deposited in Canadian National Collection of Nematodes, Ottawa, Canada. (ref. ID; 5916)

Measurements

  • Holotype (female): L=0.390 mm, a=23, b=4.5, c=14, V=84.4, spear 30.7 µm (posterior portion 10.5 µm), esophagus 87 µm long; excretory pore 82 µm from anterior end; tail 27 µm long; vulva-anus distance 35 µm. (ref. ID; 5916)
  • Paratypes: L=0.327-0.405 mm, a=18-26, b=3.8-4.6, c=14-16 (18 females), V=82.0-85.7 (N=76). (ref. ID; 5916)

    Paratylenchus projectus Jenkins, 1956 (ref. ID; 5916, 7195 redescribed paper)

    Descriptions

    Female: Body of heat-killed specimen generally curved ventrally. Sides of the head region straight, in some cases slightly depressed. Body annulation fine, about 1 µm. Annules on head region generally obscure, a few fine annules occasionally seen. The front of the head region truncate with rounded corners. Labial projection present in some specimens and absent in others. Length of spear varied from 24 to 28 µm, occasionally 28.5 to 29 µm. Spear knob about 3 µm across, slightly flattened in front, but varied slightly in shape. Dorsal gland orifice about 6 or 7 µm from spear base. Excretory pore usually at the level of the isthmus, generally less than 80 µm from anterior end. Esophagus typical of Paratylenchus. Hemizonid consists of two annules, usually in front of the excretory pore. Lateral field with four, faintly shown incisures. Anus inconspicuous in most cases. Shape of the tail terminus generally conically rounded, with the following variations: rounded, digitate, subacute, dorsally flattened, and slightly depressed dorsally. Deirids present at the level of excretory pore. Ovary outstretched, oocytes in single file, except on the region of multiplication. Spermagonium present, occasionally with one or two sperm cells. Crustaformeria well developed, the columnar arrangement of the cells usually not well displayed. Postuterine branch present, as a small sac. Two or three vestigial ovarian cells occasionally seen. (ref. ID; 7195)

    Remarks

    The shape of the tail terminus in P. projectus varied. It was usually conically rounded, but it might be subacute, bluntly rounded, slightly depressed dorsally or slightly dentate, which might appear to be slightly digitate and to a definitely digitate terminus. The tail terminus of P. neoprojectus was less variable, and a digitate terminus was rare. The location of the excretory pore apparently is of taxonomic significance in this group. In 10 populations of P. projectus reared individually, only in four females of 367 specimens examined was the location of excretory pore at 80 or 81 µm from the anterior end. In the rest, about 99% of the females, the excretory pore was less than 80 µm from the anterior end and the location could be as forward as 61 µm. In P. neoprojectus, 46% of the 114 females examined, reared from a single larva, had the excretory pore 80 µm or more from the anterior end and the most forward position was 72 µm from the anterior end. Paratylenchus nanus was quite distinct from the P. projectus group. Besides other characters, its spear knob was 6 µm across, a much stronger kob, and with a spermatheca. The topotypes of P. nanus were closely related to the P. projectus group and the possibility that it could be another species cannot be discounted. The digitate tail terminus is not only present in P. nanus, but also in P. projectus. (ref. ID; 7195)