Pratylenchus gibbicaudatus
Minagawa, Nozomu, 1982
Female. Paratypes: n = 30, L = 409-532 um
(483±34: mean standard deviation), a = 0.16-29.7 (20.0±3.6),
b = 5.3-9.5 (6.5±0.8), c = 12.8-19.0 (15.5±1.4), c’ = 1.6-3.9
(2.4±0.5), V = 69.5-77.4 (72.8±1.8), stylet = 13.9-16.4 um
(15.3±0.6), prorhabdion = 7.6-9.1 um (8.2±0.4). Holotype:
L = 507 um, a = 17.9, b = 6.6, c = 16.0, c’ = 2.1, V = 72.3, stylet
= 15.2 um, prorhabdion = 8.2 um.
Body stout, straight to open C-shape after fixation. Body
width slightly increasing around median esophagus bulb to vulva and decreasing
regularly from vulva to near tail terminus. Lip region stepped by
sides from body contour, flattened in front, with two annules, 1.9-2.5
um
(2.4±0.2) high, 6.6-8.2 um wide. Labial framework well
developed, strongly sclerotized, arch-shaped, margin extending into two
body annules. Stylet stout; knobs round or slightly flattened at
anterior surface, 1.9-2.5 um (2.1±0.2) high, 3.2-4.4 um
(4.0±0.3) wide. Dorsal esophageal gland orifice at 2.5-3.8
um
(3.2±0.3) behind stylet base. Metacorpus round, occupying
nearly whole body width, 34.7-61.9 um (51.9±5.1) from anterior
end. Esophagus 61.3-98.5 um (76.6±9.4) long from anterior
end of body to esophageal-intestinal junction. Glandular esophageal
basal lobe ended 107.4-217.9 um (131.7±25.6) from lip.
Excretory pore at 71.4-105.5 um (83.8±6.8), 15.6-20.3% (17.5±1.1)
of body from anterior end. Hemizonid located immediately in front
of excretory pore, two-annules long; hemizonion one-annule long, around
15 um posterior to hemizonid in some specimens. Lateral field
about 6.3-10.1 um wide with four incisures, inner posterior end.
Reproduction system well developed. Spermatheca round without sperms.
Postvulval uterine branch 21.5-46.7 um (33.5±8.4) long, 0.7-2.6
times (1.5±0.5) body width at vulva. Distance between vulva
and anus 2.8-4.5 times (3.3±0.5) tail length. Tail 25.3-36.6
um (31.2±2.9) long with 24-39 (30±2.5) annules. Phasmid
at posterior half of tail, 7.6-15.8 um (12.5±2.0) from tail
tip. Tail terminus annulated, truncate, or broadly rounded with shallow
notch at the top, and rarely bifurcate. Body annules faint, about
0.7-1.2 um (1.0±0.1) apart at midbody.
Male. Paratype: n= 1, L = 470 um,
a = 32.2, b = 7.9, c = 18.6, c’ = 2.0, stylet = 14.8 um, prorhabdion
= 8.2 um, stylet knob 1.9 um thick and 3.2 um wide,
spicules = 17.7 um, gubernaculums = 5.1 um. General
view similar to female but body more slender and esophagus gland less developed.
Spicules arch-shaped; gubernaculums small.
Type specimens. Holotype: female collected
by N. Minagawa on September 2, 1980. Paratypes: 30 females,
1 male and 3 larvae same data as holotype. Holotype and 28
female- and other paratype specimens are deposited in the Herbarium and
Insect Museum of the National Institute of Agricultural Sciences in Yatabe,
Ibaraki Pref. Two-paratype females are deposited in the Kyushu National
Agricultural Experiment Station, Nishigoshi, Kumamoto Pref.
Type habitat and locality. Specimens were collected
from rhizosphere of Scirpus Wichurai Böcklr. f. concolor (Maxim.)
T.
Koyama grown in a swamp adjacent to pastures in the Somma area of Mt.
Aso, Kumamoto Pref (860 m alt.).
Diagnosis. Pratylenchus gibbicaudatus n. sp. is
characterized by two lip annules and crenated tail terminus. This
species is most closely related to P. flakkensis Seinhorst, 1968,
but differs from it by flattened anterior surface of stylet knobs, more
posteriorly located phasmid, and greater number of tail annules (24-39
vs. 18-24). P. gibbicaudatus n. sp. also resembles P. bicaudatus
Meyl, 1954, which was usually treated as species inquirenda (Loof, 1960),
in the shape of tail terminus, but differs from it by smaller V-value (Meyl,
1961).