Heterodera graminophila
Golden and Birchfield, 1972
Measurements: 50 females- length (including neck), 460u
(290-650); width, 310u (160-560); 1/w ratio, 1.5 (1.1-2.1); stylet,
22.6u (21.3-23.8); outlet of dorsal esophageal gland from base of
stylet, 5.0 u (4.0-6.7).
Holotype (female)- Length, 530 u; width, 310u;
1/w ratio, 1.8; stylet, 22.0u; dorsal esophageal gland, 5.0u
Description of females: Body pearly white, basically lemon-shaped,
with protuding neck and vulva. Thick cuticle with zig-zag pattern,
subcuticular punctation, and commonly a granular surface obscuring
details of pattern. Head variable in shape, set off from neck,
bearing two annules with second one often larger than first. Cephalic
sclerotization distinct but weak. Stylet
strong and curving dorsally, with well-developed knobs sloping posteriorly.
Esophageal
region with excretory pore commonly at base of neck. Anterior
portion of neck on some specimens seen with peculiar protrusions.
Vulva prominent, and surface with wavy striae extending to vulva slit which
averages about 38 u in length. Anus small, inconspicuous,
and located approximately 20% of body length from vulva.
Measurements: 25 older cysts (washed from soil)- length
(including neck), 650 u (520-780); width, 470 u (350-560); 1/w ratio =
1.4 (1.1-1.6). Cysts light to dark brown in color, basically lemon-shaped,
with protruding neck and vulva; abullate, ambifenestrate, with prominent
underbridge having furcate ends. Vulval slit averaging about 45
u in length. External cyst pattern zig-zag, often appearing
granular and with conspicuous, irregularly arranged subcuticular punctation.
On the semifenestrae, which commonly persist even in older cysts, distinct
wavy lines extend from the outer edge to vulval slit. Anus small,
inconspicuous, without surrounding pattern, and located about 20% of cyst
length from vulval cone terminus.
Measurements: 25 males- length, 990 u (850-1110);
a = 32 (28-37); b = 6.0 (5.3-6.5) c = -; stylet, 24.7u (22.4-25.8);
outlet of dorsal esophageal gland from base of stylet, 5.3 u (4.0-6.2);
spicules 34 u (31-36); gubernaculum, 13 u (11-14).
Allotype (male)- Length, 1040 u; a
= 35; b = 5.8; c = -; sytlet, 24.4 u; outlet of doral esophageal
gland, 5.0 u; spicules, 33 u; gubernaculum, 12.4 u.
Description of males: Body slender, vermiform, tapering
slightly at both extremities. Cuticle with prominint annulation;
subcuticular annulation less distinct and appearing twice as often as on
cuticle. Lateral field without areolation, measuring about
6 u in width at midbody, gnereally with only three equally spaced
lines except two or one in anterior portion. At middle, body averages
31 u (27-35) in width. Head high, broadly hemispherical, slightly
set off, with five annules. Cephalic framework heavily sclerotized.
Median bulb ellipsoidal with its center 83 u 974-90) from anterior
end. Excretory pore about three annules posterior to the distinct
hemizonid. Spicules slightly arcuate, with bidentate tips.
Tail extremely short and with cloaca often extending beyond tail terminus.
The stylet guide in both males and larvae
appears as the usual lyre-shaped structure, plus a sleeve-like extension
reaching to approximately halfway of the basal of the stylet and ending
in a ring encircling the shaft at that point. This is the same arrangement
as described by Golden and Ellington for H. rostochiensis Wollenweber,
1923.
Description of second-stage larvae: Body vermiform, patering
at both extremities, but much more so posteriorly. Cuticle clearly
annulated; subcuticle annulation less distinct but twoice as numerous.
Lateral field without areolation, and composed of only three lines.
At widest part, body measures 22 u (20-23). Head slightly
set off, possessing five annules, and being wider at its base than in height.
Cephalic framework heavily sclerotized. Stylet strong, with prominent
inobs. Anterior and posterior cepahlids present. Prominent
median
bulb ellipsoidal, its valvated center located 64 u (59-710 from
anterior end. Excretory pore posterior and almost adjacent to hemizonid.
Tail
long,
tapering to a fine, rounded terminus. Phasmids exceptionally prominent
for a Heterodera species and located on lateral field in anterior fifth
portion of tail. Within eggs, larvae generally in four complete folds
plus a partial fifth one for the tail or portion of it.
Measurements: 25 eggs- length, 109 u (101-121);
width, 41u (37-45); 1/w ration, 2.6 (2.303.1). Egg shell hyaline,
without visible markings.
Two points about this interesting new species deserve further comment.
At first glance in the vulval cone, bullae appear to be present.
However, these structures, though seemingly bullae, are infact furcations
of the ends of the massive underbridge. They appear to have the same
texture as the underbridge, are commonly attached to it, and further unlike
bullae, occur only at either end of the underbridge. The other feature
of this species is the persistence of each semifenestra. Even in
many oldd cysts examined, the semifenestrae could still be seen, and the
disintegration and disappearance of the semifenestrae as generally occurs
in related species was not observed.
(Description-Golden and Birchfield, 1972)
DNA Sequences Obtained
