Measurements. Female: see Table 1.
Table 1. Comparison of measurements of Pratylenchus subranjani n. sp. with P. ranjani
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Mean ± SD | (range) | Paratypes mean | Paratypes (range) | Holotype | Drw1 |
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Ex. pore4 (um) |
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33.8 |
Holotype (female): L = 470 um; L’ = 438 um;
a = 27; b = 6.5; b’ = 3.8; c = 14.5; c’
= 3.2;
V = 74.9%; V’ = 80.5%; spear = 16.5 um; MB
= 73%; G1 = 25%’; G2 = 7.3%; U = 2.2; Tail/V-a = 37.8%; E.P. = 17.0%; Ph.
= 66.3%
Description. Females (n = 40): Body curved
ventrally when heat-relaxed (Fig. 1, A). Annules fine, 1.1 um
± 0.14 (0.9-1.4) wide at mid-body. Lip region medium height,
3.0 um ± (2.3-3.6) high, 8.8 um ± 0.66 (7.6-10.6)
wide, rounded and barely flattened anteriorly, mostly continuous to body
contour or very slightly off-set. Labial framework well developed,
expanding laterally, highly arched and extending into body at 2 annules.
Lip annules 3 in transmitted light, although it is occasionally difficult
to determine whether there are 3 or 4 lip annules due to continuous lip
and highly arched labial framework is apparently the 1st body annule.
SEM en face view, though distorted, showed no division between sub-median
and lateral segments, classified into “Group 1” of CORBETT and CLARK (1983).
Six inner labial sensilla are observed. No Cephalids are seen.
Spear moderately long, 1.9 times ± 0.13 (1.6-2.2) the head dia.
Spear knobs massive, 5.0 um ± 0.33 (4.0-5.6) wide, 1.9 um
± 0.23 (1.4-2.3) high: shape varies from flattened anteriorly to
acutely indented, calculated 8.5 ± 0.75 (7-10: n = 40) using
knob indices , i.e. mostly in the indented conditions and by no means rounded.
Dorsal esophageal gland orifice at 3.3 um ± 0.56 (2.6-5.3)
from spear base. Metacorpus oval, 12.5 um ± 0.88 (10.6-13.9)
long, 8.5 um ± 0.78 (6.9-9.9) across, length 1.5 times ±
0.13 (1.2-1.8) (n = 30) of width, occupying about half of the corresponding
body diameter; valve conspicuous, 52.6 um ± 3.56 (38.0-58.1)
from anterior body end, or 68.1 % ± 4.42 (59.1-76.9) of esophagus
length. Esophageal gland thin and short, extending 123.1 um
± 10.2 (97.4-155.1) from anterior body end, ventrally overlapping
the intestine 45.6 um ± 8.61 (28.4-67.3) or a distance of
2.5 times ± 0.43 (1.6-3.4) the corresponding body diameter; esophageal
glands nuclei line up. Excretory pore 103.2 % ± 7.74 (90.8-119.8)
of esophageal length or at the 75th ± 4.35 (65-85) (n = 26) body
annules from anterior body end; annules between anterior body end and excretory
pore 1.1 um ± 0.11 (0.9-1.3) in average width. Hemizonid
flat, 2.5 to 4 annules long, immediately to 3 annules anterior to excretory
pore; hemizonion lenticular, 7.2 ± 2.24 (4-12) annules posterior
to excretory pore.
Gonad outstretched, 126.7 um ± 24.1 (90.4-214.5)
(n = 39) long or 25.1 % ± 4.3 (17.4-43.5) (n = 39) of body length;
ovary with oocytes in single row; spermatheca empty, rarely observed.
Post-uterine branch long, twice as long as body diameter or longer, in
which only the columnar part of the uterus can be recognized. Vulva
plane; vulval lips slightly protruding; vagina tubular, perpendicular to
body axis, rarely slightly bent anteriorly, 8.1 um ± 0.80
(6.6-9.9) (n = 38) long or 45.6 % ± 4.44 (36.7-56.6) (n = 29) of
vaginal body diameter. Annules between vulva and anus 81.6 ±
6.0 (67-91) in number, 1.1 um ± 0.11 (0.9-1.3) in average
width.
Tail variable in shape ; sorting 40 individuals according to
tail tip shape codes of FREDERICK and TARJAN (1989), their frequencies
are: bluntly pointed (BLP) = 53 %, subhemispherical (SHM) = 30 %,
subdigitate (SBD) = 15 % and truncate (TRC) = 3 % respectively. Presence
of tail tip annules is also determined using codes of FREDERICK and TARJAN
(1989) with tails in the exact lateral orientation (28 individuals); the
frequencies then are: annulated (ANN) = 71 % (including evidently
ANN = 50 % and barely ANN = 21 %), smooth (SHM) = 18 % and cleft (CFT)
= 11 % respectively. Tail terminal cuticle or hyaline part 3.0 um
± 0.6 (1.5-4.3) thick; phasmids pore-like, centered in lateral field,
14.2 um ± 2.64 (7.9-19.1) behind anus or 18.2 um ±
3.34 (12.5-27.7) from tail tip, i.e. 56.0 % ± 7.9 (39.6-77.4) of
tail length.
Lateral fields 5.2 um ± 0.52 (4.0-6.3) wide, i.e.
27.9 % ± 2.54 (23.0-33.3) of widest body diameter. In transmitted
light, this structure appears to have weakly crenate margins and 3 equally
spaced plain bands, which gives impression of 4 incisures. The SEM
photograph, however, shows that the outer bands are areolated at intervals
of 2, 3 or even more annules in mid-body region and completely in tail
region. The middle band is often sparsely areolated and accompanied
by one or 2 accessory incisures. Lateral fields in transmitted light
appear to be closed shortly before the tail tip, but they may extend to
tail tip and continue around the tail terminus.
Males: Unknown.
Type host and locality. Specimens were collected
from roots and rhizosphere of maize, Zea mays at Pukae, Phraphutthabat
district, Saraburi province, Thailand.
Type material. Collected on January 12, 1989 and
May 23, 1989 by Y. TOIDA and S. KEEREEWAN. Holotype (female:
Type no. 28-1) and paratypes (30 females and 10 juveniles) are at the Herbarium
and Insect Museum of the National Institute of Agro-Environmental Sciences,
Tsukuba City, Ibaraki, Japan. Paratypes (10 females) are also at
the Nematology Section, Department of Agriculture, Bangkok, Thailand.
Diagnosis and relationships. Pratylenchus subranjani
n. sp. shows a close relationship with P. ranjani KHAN and SINGH,
1975 by having rather low V-value (73-77 %), rather low c-value (13.2-18.3),
fine annule (0.9-1.3 um), numerous tail annules (21-32), and a long post-uterine
branch (29-54 um). The new species can be distinguished by the presence
of 3 lip annules (4 in P. ranjani), position of hemizonid (1-3 annules
vs. 5 annules anterior to excretory pore), E.P. value (14.3-18.1 % vs.
13.4 %).
The other species sharing V-values close to 73-77 % or the lip
regions bearing 3 or 4 annules with P. subranjani n. sp. are P.
barkati DAS and SULTANA, 1979; P. dasi FORTUNER, 1985; P.
delattrei LUC, 1958; P. exilis DAS and SULTANA, 1979; P.
goodeyi SHER and ALLEN, 1953; P. morettoi LUC et al., 1986;
P.
mulchandi NANDAKUMAR and KHERA, 1970; P. nizamabadensis MAHARAJU
and DAS, 1981; P. pratensis (DE MAN, 1880); P. pseudopratensis
SEINHORST,
1968; P. singhi DAS and SULTANA, 1979; P. thornei
SHER and
ALLEN, 1953; and P. zeae GRAHAM, 1951.
On the basis of the ranges in the measurements, the new species
cannot be conveniently separated from some of these other species, especially
those assigned to the “pratensis group” by FREDERICK and TARJAN (1989).
Differences between P. subranjani n. sp. and these species are indicated
in bold letters (Table 2).
Species | V | Spear (um) | U | C | Knob idx1 | Lip ann. | Tail ann. | Tail code2 | Males code3 |
Subranjani n. sp. | 754 (73-77)5 | 17 (16-19) | 2.3 (1.6-3) | 16 (13-18) | 8.4 (6-10) | 3 (3-4) | 27 (21-33) | Bip-shm/ann-smo | UK |
barkati | -
(74-79) |
-
(18-19) |
1 (-) | -
(17-21) |
9 (-) | 3 (-) | - (18) | Shm-sbd/ann | UK |
dasi | -
(72-78) |
-
(18-19) |
-
(1-1.5) |
-
(14-21) |
-
(4-5) |
3 (-) | -
(20) |
Shm/smo | UK |
delattrei | 75 (73-80) | -
(16-18) |
-
(1.3) |
-
(18-22) |
7 (-) | 3 (-) | -
(<20) |
Shm-blp/smo | UK |
exilis | -
(73-76) |
-
(17-18) |
-
(0.9-1) |
-
(15-20) |
-
(6-7) |
3 (-) | -
(17-20) |
Shm-blp smo | K |
goodeyi | -
(73-75) |
-
(16-17) |
1 (-) | -
(16-18) |
7 (-) | 4 (-) | 22 (19-24) | Fnp-dlg/smo | K |
morettoi | 76 (73-80) | 16 (14-19) | 2.7 (2-3.4) | 15 (13-19) | - (3-4) | - (3-4) | - (-) | Fnp-dlg/- | K |
mulchandi | 77 (75-78) | -
(16-20) |
-
(1.8) |
22 (17-27) | 6 (-) | 3 (-) | - (16-22) | Trc-shm blp-smo | UK |
nizamabadensis | -
(67-79) |
-
(17-19) |
-
(1.3) |
-
(17-27) |
3 (-) | 4 (-) | -
(15-24) |
Hem/ann | UK |
pratensis | 75 (74-78) | 16 (14-16) | - (>1) | 19 (14-27) | 5 (-) | 3 (-) | - (20-28) | Shm-blp/smo-ann | K |
pseudopratensis | 79 (76-80) | 14 (13-15) | 1 (-) | 22 (19-27) | 7 (-) | 3 (3-4) | 15 (12-19) | Hem-shm/smo | K |
ranjani | 75 (73-78) | 16 (15-17) | 2.0 (-) | 17 (12-21) | 5-6 (-) | 4 (-) | -
(25-35) |
Hem-shm/smo | UK |
singhi | -
(75-77) |
-
(17-18) |
- (<1) | -
(18-23) |
6 (-) | 3 (-) | - (-) | Shm/smo | (UK) |
thornei | 76 (73-80) | 17 (15-18) | -
(>1.5) |
20 (19-25) | -
(5-7) |
3 (-) | 23 (19-26) | Trc/smo | R |
zeae | 73 (69-75) | 16 (15-17) | 1 (-) | 16 (17-21) | -
(6-9) |
3 (-) | 25 (21-26) | Blp/smo-ann | UK |