Table III
Frequencies of different numbers of annules on female tails in the
type and other populations of P. fallax.
No. of annules | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | Total |
No. of specimens type pop. | 2 | 4 | 2 | 4 | 12 | 8 | 15 | 4 | 5 | 1 | 1 | 58 |
No. of specimens five other populations |
4
|
1
|
4
|
3
|
11 | 12 |
8
|
9
|
7
|
6
|
2
|
|
No. of specimens total |
6
|
5
|
6
|
7
|
23 | 20 | 23 |
|
12 |
7
|
3
|
|
Cephalic framework with thin posterior edges extending about two
body annules into body. Stylet with anteriorly flattened or forward-pointing
knobs. Dorsal oesophageal gland opening 2 or 3u behind spear
knobs. Excretory pore at or posterior to level of nerve ring.
Ovary outstretched, oocytes in single file except for a short
region near anterior end. Spermatheca round, sometimes empty and
then narrower and longer. Distance between vulva and spermatheca
42% to 71% of that between vulva and anus. Length of postvulvar uterine
branch about one-fourth to one-third of distance between vulva and anus;
posterior part often consisting of two or three rudimentary elements.
Male (allotype): L = 0.46mm; a = 27; b =
6.2; c = 21; T = 32; stylet = 15u; spicules = 15u.
Testes with double row of spermatocytes. There is about
one male per 5 females.
Holotype: female, collected by J.W. Seinhorst, March 1965,
slide no. TC 9/1 I.P.O. Nematode Collection, Wageningen.
Allotype: male, same data as holotype, slide no. TC 9/2,
I.P.O. Nematode Collection, Wageningen.
Paratypes: 41 females and 15 males, same data as holotype,
slides TC 9/3-9/10 I.P.O. Nematode Collection, Wageningen and one slide
with females and males in each of the following places, Plantenziektenkundige
Dienst, Wageningen; Rothamsted Experimental Station, Harpenden, Herts,
England; Plant Industry Station, Beltsville, Md., U.S.A. and Nematology
Department, University of California, Davis, Cal., U.S.A.
Type locality: apple orchard near Doornenburg, The Netherlands.
Type habitat: apple orchard with grass undergrowth on loam
soil.
Relationships
P. fallax is most closely related to P. penetrans, from
which it differs only in having a crenate tail tip. The species differs
from P. convallariae in having more and narrower annules on the
tail (generally fewer than 20 in P. convallariae), in being
smaller and in the lower ratio of males to females (almost 1:1 in P.
convallariae). Females with an empty spermatheca can be distinguished
from P. crenatus by the shorter postvulvar uterine sac (length 25%
to 35% of the distance between vulva and anus, against almost 50% of this
distance in P. crenatus).
P. fallax is distinguished from P. pratensis by
the round spermatheca, which is placed more posteriorly than in P.
pratensis.
Moreover, P. fallax is less slender than
P. pratensis.
It is easily distinguished from P. irregularis Loof (1960) by the
shape of the tail tip and differs from P. cerealis Khak, 1966, in
the more posterior position of the excretory pore, the tail not being particularly
short and the lip annules being rather flat and obscure.
P. fallax is widespread in the Netherlands. It occurs
especially in meadows and orchards on loam and sandy loam soils and in
places with a more or less natural vegetation. It is rare in arable
land on sandy soils. Unlike P. penetrans the species most
probably is indigenous to the country. It has probably not been reported
before because it was confused with P. penetrans, P. crenatus
and perhaps occasionally P. pratensis. The species was also
found in samples from Rochefort, France; Naples, Italy and in England,
being the unnamed species of Pitcher, Way & Savory (1966) and of Corbett
& Webb (1967).