Indi4n {. Nemato/.
OBSERVATIONS
ON THE MORPHOLOGY
XIPHINEMA
ZAHRA
Section of Nematology,
OF ADULTS AND JUVENILES OF
COBB, 1913
AMERICANUM
MALIK and M. SHAMIM
Department
14(2), (1984) : 152-159
JAIRAJPURI
of Zoology, AIi~arh Musliqt University,
A)igarh 202001, India
Abstract: Observations on the morphology of adults and juveniles or Xiphinema americanum are based on the study or a very large number of specimens collected from the campus
of Aligarh Muslim University, AIigarh, during different periods of the year. Both sexes
occur though males are extremely rare and their role in reproduction is doubtful.
The
four juvenile stages can easily be distinguished
from each other as well as from the adults on
the basis of their body length, size of functional and replacement
odontoslyle, size of genital
primordia etc.
Key words:
Xiphinema americanum, Qlorphology
Xiphinema americanum
Cobb, 1913 is a
widely distributed
species and has been
reported from almost all the countries of the
world.
In India, it was first reported from
Aligarh by Siddiqi (1959) and later by many
workers from other localities
(Janarthan
et al., 1969; Bajaj and Jairajpuri,
1979;
Sethi and Swarup, 1969; Sharma et al., 1969
etc). Lima (1965) concluded
that X. americanum represented a species-complex
along
with X. brevicolle Lordello
& Da Costa,
196 I, X. opisthohysterum
Siddiq i. 196 I and
"four undescribed
species". Tarjan (I968)
studied the variability within different populations and regarded
them as geographical
variants of X. americanum. He, however,
considered
X. brevicolle, X. opisthohysterum
and "the four undescribed species" of Lima
valid and different
from X. americanum.
Recently,
several populations,
previously
identified
either as X. americanum or X.
brevicolle, were described as 15 new species
by Lamberti & Bleve-Zac.heo (1979). Keeping in view the existing confusion about the
systematics
of X. americanum and also its
wide occurrence in India, it was decided to
study this species, both adults and juveniles,
and record detailed
observations
on its
morphology and anatomy.
MATERIALS
AND METHODS
The nematode,
X. americanum,
was
collected
from within the campus of the
Aligarh Muslim University,
Aligarh from
soil around roots of mast trees (Pol)'athia
longefolia)
in· different
months
during
1980-81. The measurements
and observations were made on specimens mounted in
dehydrated
glycerine after being killed in
hot 4 per cent formalin and dehydrated by
the slow method.
The transverse
sections
were cut in glycerine jelly with an eye-knife
and mounted
in the same medium.
The
detailed description of the adults and various
juvenile stages is given below.
OBSERV ATlONS
Adults (Fig.
J
& 2)
Sexes a Imost similar in shape and size.
Body 1.6-2.4 mm long, slender, assuming
closed 'c' or spiral shape upon death.
Cuticle 2-3 fLm thick at midbody and 7-8
fLm on tail, many layered, outer and inner
cuticle marked
with fine striae.
Dorsal,
ventral and lateral
series of body pores
pres~ntl laterals vi~ible tl1fl;mout body whil~
MORPHOLOGY
OF AOUJ,.TS AND JVVENILES
OF XIPHINBMA
AMERICA NUM
20um
E
F
Fig. 1. A. Entire female, B. Lip region showing amphids, C. Anterior extremity, D. Female
~onad, E. Femal~ tail, F. Oesophageal bulb, G. Male tail.
153
154
ZAHRA MAUl(; AND M, SHAMIM lAIR~lPlJRI
I
IA-G,H &
~
I
AF
JOJ,Jm
E
10J,Jm
~
G
Fig. 2.
C
H
Cross sections of body of the adults, A. En face view, B. At level of odontostyle. C. At
level of guiding ring, D-F. At various levels of basal flanges, G. At level of oesophageal
bulb, H. At level of vagina, I. At level of rectum.
dorsal and ventral pores confined to anterior
end of body. Lateral chords one-sixth to
one-third of midbody width, hypodermis
separated from cuticle by a thin basement
membrane.
three-fifths of labial-width wide, located at
base of lip region.
Odontostyle 74-87 fLmor 8-9 labial-widths
long, odontophore 40-56 fLm long with
prominent flanges. Basal guiding ring situaLip region 9-11 fLm wide and 3-5 fLm ted at 6-7 labial-widths from anterior extrehigh, rounded, set off from body contour by mity.
a constriction. En face view lihows six lips
each bearing a papilla on inner circlet and
Expanded part of oesophagus 54-75 !Lm
a papilla on the outer. The submedian lips long or 23-25 per cent of total oesophageal
bear an additional papilla each. Amphids length. Cardia short and conoid. Nerve
stirrup-shaped, apertures slit-like, half t9 rin~ abotlt tWO laQial-wiqth~ from Qase of
MO}tPItOLOGY
of! ADULTS
ANb
JUVENltES OF XIPHINEMA AMEincANtJM
odontophore.
Intestine composed of six
cells in circumference, displaced dorsally in
the region of gonads. Prerectum 5-7 anal
body-widths long, distinguishable from intestine in being narrow and its cells having
fewer granules. Rectum about one anal
body-width long.
Female reproductive system amphidelphic, reflexed. Each sexual branch consisting
of an ovary, a distal narrow and a proximal
expanded part of oviduct, and a muscular
uterus. Vagina thick-walled, about onethird of corresponding body-width long.
Organ-Z, pseudo-organ-Z or other uterine
differentiation not present. Uterine eggs
light brown, elongate-oval measuring 10U200 X 16-24 [Lm. Vulva a transverse slit
located at mid body.
Males extremely rare Cl : 1000) and their
role in reproduction doubtful. Male reproductive organs comprise a pair of testes
extending in opposite directions and each
connected to a short seminal vesicle uniting
to from vas deferens. 'fhe latter leads to
ejaculatory duct which gradually narrows
posteriorIy and joins rectum to form cloaca.
Spicules about two anal body-widths long
along median axis. Lateral guiding pieces
obscure. Supplements consist of an ad anal
pair and a series of 5-7 ventromedians.
Tail short, convex-conoid, 28-48 [Lm or
anal body-widths long with two
caudal papillae on either side
1.1-2.0
JUVENILES
(Figs. 3-5)
First stage juvenile :
Body 0.57-0.59 mm long. Lip region
rounded, set off from body contour, 7-8 p.m
wide, 2-3 I-'m high. Functional odontostyle
38-42 [Lmor 5-6 labial· widths long. Odontophore about four-fifths of odontostyle length.
Basal guiding ring 4-5 labial-widths from
anterior extremity. Replacement odontostyle
42-49 [Lmor 6-7 labial-widths long, with it
anterior end lying enclosed within walls of
odontophore, a characteristic feature of the
first stage juveniles of Xiphinema (Coomans
IS;
& De Coninck, 1963).
Basal oesophageal
bulb 32-40 p.m long or 22-25 per cent of neck
length. Nerve ring at 8-12 [Lm from base of
odontophore. Rectum 5-6 pm long. Genital
primordium 7-8 p.m situated near middle of
bbdy and consists of two cells. Tail short,
convex-conoid, ventraIly curved, 22-27 p.m
or 2.0-2.7 anal body-widths long, with two
caudal papillae on either side.
Second stage juvenile
Body 0.6-0.8 mm long. Lip region
markedly set off from body contour, 8-9 p.m
wide, 3-4 p.m high. Functional odontostyle
43-45 [J.mor 5-6 labial widths long. Odontophore about three-fifths of odontostyle
length. Fixed guiding ring 4-5 labial-widths
from anterior extremity. Replacement odontostyle 50-54 [Lmor 6-7 labial-widths long,
enclosed within the walls of anterior slender
part of oesophagus. Basal oesophageal bulb
38-45 [J.m long or 17-23 per cent of neck
length. Nerve ring at 8-12 [J.mfrom base of
odontophore. Rectum 7-8 [J.mlong. Genital
primordium 14-16 [J.m, consists of four
cells. Tail short, conoid, 22-31 [Lmor 1.1-2.7
anal body-widths long with two caudal
papillae on both side.
Third stage juvenile
Body 0.8-1.2 mm long. Lip region
markedly set off from body contour, 9-11
[J.mwide, 3-4.[Lm high. Enface view showing
six lips, bearing three papillae on each submedians, and two on each lateral lip.
Functional odontostyle 46-55 [Lm or 5-6
labial-widths long. Odontophore three-fifths
of odontostyle length. Fixed guiding ring at
4-5 labial-widths from anterior extremity.
Replacement odontostyle 61-67 [1.mor 6-7
labial-widths long. Basal oesophageal bulb
42-50 !J.mlong, occupying 17-23 per cent of
neck length. Nerve ring 10-12 [J.mfrom base
of odontophore. Intestine composed of six
cells in circumference. Prerectum distinguishable from intestine. its cells have fewer
granules. Rectum 9-11 [J.mor 0.6-0.7 anal
body-width long. Genital primordium 21-24
[J.m, consists of eight cells. Tail short,
conoid, 24-48 pm or 1.7-2.5 anal body-
1%
ZAHRA MAtlK AND M. SItAMtM JAtRAtPtilH
W
I
iJ
«
E
:J
oIf)
1I
I
II!
-.UI,!;;:J;i.
I
III
III
111'········J'IIH
lL.
1IIIIirr.·:)i]
..~
1'1
III
111:(:·:····11
lit;:::·'
III
11
III
Fig. 3.
ll:,;·····::l·'1
11 ~;:.:
'. ':'~:
::.::.' . .'
::: I
11
I···
t:.·......
:·.::jj,1
A. Entire female, B. Fourth stage juvenile, C. Third stage juvenile,
juvenile, E. First stage juvenile,
F-I. Genital primordia
of L"
respectively.
D. Second stage
L3, L2 and Ll
MOIlPHotOGYOF
Fig. 4.
AbULTS ANb n.iVliNtLM 017j,tpltlNEMA
AMEIlICANUM
A. Oesophageal
region of adult. B-E. Oesophageal
region of Lt,
respectively, F. Female llnl, G-J. Tails of L4,-I,.f, L2 and Ll respectively.
La, L2 and Lt
151
158
ZAHRA MAUl( AND M. SHAMIM 1AIltA1PUR'
'----"'" B
G
,B\,
........
\ •.g(' .....
H
~
~F
Ae
20um
J
Pig. 5.
fA-K
o
c
K
E
Cross sections of body of juveniles, A-E. Third stage juvenile, A. Ell face view, B. At
level of basal flanges, C. At level of replacement odontostyle, D. At level of basal
oesophageal bulb, E. At level of intestine.
P-K. Fourth stage juvenile, F. En face view, G. At level of functional odontostyle,
H. At level of basal flanges, 1. At level of replacement odontoslyle, J. At level of
intestine, K. At level of genital primordium.
widths long
both side.
with
two
caudal
papillae
on
Fourth stage juvenile
Body
1.1-21 mm long.
Lip region
markedly set off from body contour, 9-11
(l.m wide, 4-5 [Lm high. Enface
view same
as third stage juvenile.
Functional
odontostyle 61-74 [lom or 6-8 labial-widths
long.
Odontophore
about three-fifths of odontostyle length. Fixed guiding ring at 5-7 labialwidths from anterior extremity. Replacement
odontostyle
76-87 (Lm or 7-9 labial-widths
long. Basal oesophageal
bulb 48-60 (Lm
long, occupying
20-25 per cent of neck
length. Nerve ring at 13-18 (Lm from base
of odontophore.
Prerectum
more clearly
distinguishable
from
intestine
in being
narrow and its cells having fewer granules.
Rectum 10-16 [Lmor 0.6-0.7 anal body-width
long.
Genital primordium
elongate oval,
30-34 [Lm long, consists of sixteen cells, a
hyaline area indicates place of formation of
future vulv~. Tail short, conoid, 30-44 p.m
MRRPHOLOGY
OF ADULTS
AND JUVENILES
or 1.3-2.4 anal body-widths long with two
caudal papillae on both side.
Remarks
The present population of X. americanum
from Aligarh conforms with the Canadian
population described by Lamberti & BleveZacheo (1979) except for some minor differences. The specimens from Aligarh are
slightly longer, have a narrower body,
smaller oesophagus, longer odontophore and
slightly shorter tail (L= 1.5-1.8 mm; a=
46-54; b=4.7-8.0; odontophore=38-50 fLm;
c=43-S1 in the adult specimens as described
by Lamberti & Bleve·Zacheo, 1979).
The authors are thankful to Prof. Nawab
H. Khan, Chairman of the Zoology Department for providing necessary laboratory
facIlities. The first author thanks the University Grants Commission for financial
assistance.
REFERENCES
BAlAJ, H.K. & JAIRAJPURI. M.S. (1979). A review
of the genus Xiphinema Cobb, 1913 with
descriptions of species from India. Rec.
Zool. Surv. India 75: 255-325.
COOMANS,' A. & DE CONINCK, L. (1963). Observations on spear formation
in X'phinema.
Nematologica 9: 85-96.
OF XIPHINEMA
AMERICANUM
159
JANARTHAN, R .. SBSHADRI. A.R. & SUBRAMANIAM. T.R. (1969). Studies on Xi phinema spp. and Longidorus spp. from Madras state. All India Nematology Symposium,
New Delhi, August 1969, 21-22: 34.
LAMBERTI, F. & BLEVE-ZACHEO, T. 1979).
Studies on Xiphinema americanum Sensulato
with descriptions
of fifteen new species,
(Nemotoda
: Longidoridae).
Nematol.
medit. 7 51-106.
LIMA, M.B. (1965). Studies on species of the
genus Xiphinema
and other nematodes.
Ph. D. thesis University London, 165 pp.
SETHI, C.L. & SWARUP, G. (1969).
and distribution frequency of
sitic nematodes with temperate
in Himachal Pradesh. All India
Symposium New Delhi, August
24.
Association
plant-parafruit trees
Nematology
1 69, 21-2~ :
SHARMA, BB., SHARMA, H.C. & KHAN, E. (1969).
Nematodes associated
with sweet orange
and mandarin plants in relation to Diebaek.
All India Nematology
Symposium,
New
Delhi, August 1969,21-22: 16.
SIDDlQI, M.R. (1959). Studies on Xiphinema spp.
(Nematoda : Dorylaimoidea)
from A1igarh
(North India), with cemments on the genus
Longidorus Mieolelzki,
1922. Proc. Helminth. Soc. Wash. 26: 150-163.
T ARJAN, A.C. (1968). Variability in: Xiphinema
americanum Compt. Rend. VIII Symp.Int.
Nemato/. Antibes, 1969, France. E.J. Brill,
Leiden, Holland, p. 29.
Accepted for publication
: March, 1984