Aphelenchus
Aphelenchus Bastian, 1865
Subphylum Secernentia: Order Tylenchida: Suborder Aphelenchina: Family Aphelenchidae (ref. ID; 1276)
Order Tylenchida (ref. ID; 6180)
Suborder Aphelenchina: Family Aphelenchidae (ref. ID; 3547)
Family Aphelenchidae (ref. ID; 5951, 6168, 6182, 6740)
ref. ID; 1923
Female tail bluntly rounded. (A small genus of fungivorous forms) (ref. ID; 1923)
ref. ID; 3547, 6153, 6691
Fungivores. (ref. ID; 3547, 6153, 6691)
ref. ID; 5951
Subgenus: Anaphelenchus (ref. ID; 5951 original paper)
Diagnosis
Aphelenchidae. Parthenogenetic and gametogenetic species. Vagina very weakly developed; its wall symmetrical, isomorphic. Cuticle of vulval lips not or only slightly thickened. (ref. ID; 5951)
Remarks
Species in the nominate subgenus Aphelenchus differ from those of Anaphelenchus in having a strongly developed, anisomorphic vagina and prominently thickened vulval lips as shown by Aphelenchus avenae (Bastian, 1865). (ref. ID; 5951)
Type species
Aphelenchus (Anaphelenchus) isomerus (ref. ID; 5951)
ref. ID; 6859
Hyphal feeder. (ref. ID; 6859)
- Aphelenchus avenae Bastian, 1865 (ref. ID; 1756, 2588, 3547, 5951)
- Aphelenchus avenae (Goodey, 1963) (ref. ID; 1767)
- Aphelenchus (Anaphelenchus) isomerus Anderson & Hooper, 1980 (ref. ID; 5951 original paper)
- Aphelenchus parietinus Bastian, 1865 (ref. ID; 3439)
- Aphelenchus solani (Steiner, 1935) Goodey, 1951 (ref. ID; 5951)
Descriptions
Soil nematode. (ref. ID; 1767)
Aphelenchus (Anaphelenchus) isomerus Anderson & Hooper, 1980 (ref. ID; 5951 original paper)
Diagnosis
Aphelenchus isomerus n. sp. is distinctive because of its isomorphic vagina, width of the lateral field, which extends about a body width, and by its fine, often obscure body annulation. In other charactes it is like A. avenae as defined by Hooper (1974). Aphelenchus solani (Steiner, 1935) Goodey, 1951 also was collected with potatoes from Cuba. This species differ from A. isomerus by its shorter postuterine sac (about body width long versus more than three body widths) and in stylet length (20 µm versus 11-14 µm in A. isomerus). The structure of the vagina could not be resolved in the types of A. solani provided by Dr. A.M. Golden, Beltsville, MA. Steiner illustration, however, shows the vagina to be anisomorphic Isonchus (= Aphelenchus) radicicolus Cobb, 1913 was not available and Cobb's notes of 1909 state the relative size of the vagina only, which is consistent with that of A. avenae. Types of other species examind were Metaphelenchus rhopalocercus Steiner, 1941 and M. micoletzkyi Steiner, 1942, also provided by Dr. A.M. Golden. Females of these species had anisomorphic vaginas which further supports their synonymy with A. avenae by Goodey and Hooper (1965). A new subgenus is proposed to accommodate those species with an isomorphic vagina. (ref. ID; 5951)
Descriptions
Holotype (female): Body linear, midbody width 20 µm, body annules 0.5 µm. Excretory pore 88 µm from anterior extremity, about a body width behind metacorpus. Hemizonid indistict. Isthmus 33 µm long esophageal gland lobes 60 µm long, in tandem. Female monodelphic, prodelphic, ovary extending anteriorly 290 µm. Postuterine sac 64 µm long, 58% of vulval-anal distance. Tail subcylindrical, terminus rounded. Phasmids subterminal. (ref. ID; 5951)
Paratypes (9 females): Body slender, linear to slightly arcuate when relaxed. Body width 16-28 µm, annules very fine about 0.5 µm wide often obscure, interior cuticular annulation more prominent. Lateral field very wide, about a body width, with at least 14 incisures at midbody (14 in cross section of one paratype). Head low, broadly rounded, apex often flattened. Lips continuous with body contour or slightly set off by a shallow constriction. Verstibule lining cuticularized. Esophagus 124 µm (99-138) to esophago-intestinal valve, 177 µm (148-203) to end of gland lobes, lobes 36-66 µm long, in tandem. Metacorpus ovate to rarely hexagonal, dimensions 21 µm (19-24) x 15 µm (12-17). Valve plates of metacorpus 5-8 µm long. Isthmus 38(29-46) µm long. Nerve ring surrounding isthmus from near base of metacorpus to 7 µm posterior. Excretory pore 88 µm (74-110) from anterior extremity, 12 µm (7-17) behind metacorpus; in one female at level of anterior end of metacorpus, in anthor at posterior end of metacorpus. Hemizonid (5 females) 5-7 µm behind excretory pore, indistinct in other paratypes. Deirid 20 µm (12-29) behind level of metacorpus base, always at level of hemizonid or posterior. Anterior reproductive system 308 µm (202-488) long, outstretched, 46%(40-53) of body length. Ovarial epithelium a double row of prominent cells, becoming flattened and displaced in region of advanced oocytes. Oocytes in single row, obscured by epithelial nuclei in early stages of oogenesis. Vulval lips not thickened. Vagina isomorphic, weakly developed. Postuterine sac 72 µm (57-93) long, 54%(48-59) of vulva-anus distance, collapsed. Tail cylindrical to subcylindrical, 25 µm (20-29) long. Terminus hemispherical, sometimes obliquely flattened. Phasmids subterminal. (ref. ID; 5951)
Male: Unknown. (ref. ID; 5951)
Type locality and host
Cuba, associated with potatoes. (ref. ID; 5951)
Type designations
Holotype (female), type slide No.242, collection No.6584. (ref. ID; 5951)
Paratypes (9 females), type slide Nos.242a-f. Deposited in Canadian National Collection of Nematodes, Ottawa. Three female paratypes deposited in the Rothamsted Nematode Collection, Harpenden. Herts., England. Two paratypes deposited in the U.S. Department of Agriculture Nematode Collection, Beltsville, Maryland. (ref. ID; 5951)
Measurements
Holotype (female): L=638 µm; a=30; b=5.6; b'=3.6; c=21; c'=2.3; V=79. Stylet length=12 µm; M=38. (ref. ID; 5951)
Paratypes (9 females, 6 measured): L=689(499-926) µm; a=33(26-37); b=5.7(4.9-7.7); b'=4.1(3.4-4.9); c=28(22-32); c'=1.9(1.6-2.2); V=77(75-78). Stylet length=13(11-14) µm; M=35-44. Egg (1, intrauterine): 62 µm x 20 µm. (ref. ID; 5951)