Hashim, Z.

Horizon / Pleins textes

Description of Pratylenchus jordanensis n. sp. 
(Nematoda : Tylenchida) and notes on other Tylenchida 
frsm Jordan 
Zeid H ASHIM 
Deparlment of Agricullural  Research & Extension,   Minis try  of Agriculture,  
P.O. B o x  326, A m m a n ,   J o r d a n .  
S U M M A R Y  
Pratylenchus jordanensis n. sp., recovered lrom the rhizosphere of grapcvine in Jordan, is dcscribed and illus- 
trated. Its main diagnostic features are absence of males, spermatheca devoid of spermatozoa, cephalic region 
slightly offset from  the  body  and  with two  annules,  short  stylet (14.6 pm) with  anteriorly  directed  knobs, V coeffi- 
cient of 77.8, presence of intestinal fasciculi, undifferentiated  post-vulval  sac (16.2 pm in  length),  four incisures in 
the  lateral field (often  with  additional  oblique  striae  in  the  central  band  at  mid-body), conoid tail  with 21 annules 
and  smooth  tail  terminus  with  a  characteristic  indentation.  Notes  are also given on certain morphological features 
of Helicotylenchus  microcephalus Sher, 1966, Tylenchorhynchus clarus Allen, 1955 and T .  goffarti Sturhan, 1966 
found  in  Jordan. 
RÉSUMÉ 
Description de Pratylenchus  jordanensis n. sp.   (Nematoda : Tylenchida)  
et notes sur  d’autres  Tylenchida  de  Jordanie 
Pratylenchus  jordanensis n.  sp.,  provenant  de la rhizosphère  de  vigne ( V i t i s  sp.) en Jordanie,  est  décrit  et  illustré. 
Ses grands  traits  diagnostiques  sont  l’absence  de  mâles,  la  spermatheque  dépourvue de spermatozoïdes,  la  région 
céphalique  légerement  séparée e t  avec  deux  anneaux,  un  stylet  court (14.6 Pm)  avec  boutons  basaux inclinés anté- 
rieurement,  un coefficient V de 77,8, la présence de fasciculi intestinaux,  un sac  post-vulvaire  long  de 16 pm et  non- 
différencié, quatre incisures dans le champ  latéral  (des  lignes obliques  supplémentaires  apparaissent  souvent  dans 
la  bande  centrale, à mi-corps),  une  queue  conoïde  comportant 21 anneaux, en  moyenne, et une  extrémité lisse avec 
une dentelure caractéristique. Des notes sont par ailleurs données sur Helicotylenchus microcephalus Sher, 1966, 
Tylenchorhynchus clarus Allen, 1955 et T.  goffarti Sturhan, 1966 trouvés en Jordanie. 
A new species of Pratylenchus Filipjev, 1936 was 
isolated from soil around roots of grapevine grown 
under  irrigation  in  Wadi  Dhulail,  Jordan. It is 
described herein as P. jordanensis n. sp. Notes are 
also given  on  certain morphoIogica1 features of 
Helicotylenchus  microcephalus Sher, 1966, Tylencho- 
rlzynchus clarus Allen, 1955 and T. gof farf i  Sturhan, 
1966 found  in  this  country. 
Materials  and  methods 
Nematodes  were  extracted  from soil by a tray 
modification of the  Baermann  funnel  method  [White- 
head & Hemming,  1965).  Specimens  were  subse- 
quently killed by  heat, fixed in  TAF,  stained  in  hot 
(60-650) lactophenol  containing  either Cotton blue 
(P.  jordanensis  n.  sp.) or  acid  fuchsin  (the  other 
nematodes)  and  finally  processed to  anhydrous 
glycerol  containing  traces of picric  acid by  the  rapid 
method of Baker  (1953).  A  Zeiss  Photomicroscope III, 
fitted  with an ocular  micrometer  and a camera  lucida, 
was used for measuring  and  drawing  the  specimens. 
Standard error of the mean has been calculated for 
each of the  main  measurements  and coefficients. 
Revue  Nèmatol. 6 ( 2 )  : 187-192 (1983) 187 
Z. H a s h i m  
Pratylenchus  jordanensis n. sp. 
(Fig. 1 A-H) 
DIMENSIONS 
Hololype female : L = 0.43 mm ; a = 29 ; b = 
5.2 ; b’ = 3.5 ; c = 16.5 ; C’ = 2.9 ; V = 30.5-79.3-3.3 ; 
stylet = 14.5 pm. 
Paralype  females  ( n  = 14) : L = O .  49 f 0.014 
(0.38-0.59) mm ; a = 29 f 0.49 (26-32) ; b = 5.3 f 
0.10 (4.5-5.9) ; b’ (n  = 13) = 3.8 f 0.08 (3.2-4.1) ; 
c ( n  = 11) = 18.3 f 0.88 (16.1-25.0) ; cf ( n  = 11) = 
stylet = 14.6 f 0.05 (14.5-15.0) pm. 
2.6 f 0.12 (2.1-3.0); V = 77.8 f 0.25 (75.1-79.1) ; 
DESCRIPTION 
Pemales  : Body  almost  straight  to  ventrally  arcuate 
when  killed by  heat.  Annule  width 1.0-1.5  pm a t  mid- 
body.  Lateral field about  1/3 of mid-body  diameter, 
non-areolated and  with  four  incisures ; additional 
oblique  striae  often  occur  in  *the  central  band of 
lateral #field a t  mid-body. In%&g, incisures smooth, 
fusing  in the oesophageal and caudal regions ; outer 
incisures  crenate. Cephalic  region  low, 2.0-2.5 pm 
high, with two annules and slightly offset from the 
body.  Cephalic  framework  sclerotized,  with the  outer 
margins  extending  into  the  body for almost  wo 
annules. Stylet knobs indented anteriorly. Vestibule 
extension 9-10 pm long. Anterior cephalids 2-3 an- 
nules  behind  cephalic region ; posterior  cephalids 
rarely observed, 8-9 annules behind cephalic region. 
Excretory pore 1-13 annules anterior to  the  oeso- 
phago-intestinal junction, from 1-6 annules behind 
hemizonid and  at  81.2 f 1.52  (67-90) pm from  ante- 
rior end. Hemizonid 2-3 annules long. Hemizonion 
observed in  four  specimens, 5-9 annules  behind 
excretory pore. Orifice of dorsal oesophageal gland 
3.4 f 0.06 (3.0-3.5) pm from stylet base.  Median 
oesophageal bulb 12.5-14 x 8.5-10 pm. Oesophageal 
glands overlapping the intestine, with the longest 
overlap ventrally situated and 39.0 f 2.28  (29.0- 
52.5)  pm  long ; gland  nuclei  arranged  almost  in 
tandem. Convoluted  canals (= intestinal  fasciculi) 
present  in the  intestinal  region : in a few  specimens, 
extensive  portions of these  canals  are  evident, 
appearing  to  interwine  and, a t  least  occasionally, 
anastomose ; in others, only exceedingly short sec- 
tions of the canals could be discerned, possibly due 
I o  the almost complete collapse of these structures 
during  fixation  and/or processing. Post-rectal  sac 
absent.  Vulva  raised  on a protuberance.  Vagina  about 
1/2 of vulval  body  diameter.  Genital  tract  monodel- 
188 
~ ~~ ~~ ~ 
phic, prodelphic and 134.1 Ij, 4.81 (103.5-163.5) pm 
long. Columella distinct,  but  the  number of rows of 
cells not  determined.  Spermatheca  devoid of sperm- 
atozoa,  sometimes  dificult  todiscern.  Oocytes 
arranged in a single row within ovary. Post-vulval 
sac  16.2 f 0.74 (13.0-20.5) pm  long,  undifferentiated. 
Tail  conoid,  with 21.4 f 0.47  (19-24)  annules  (ventral 
side).  Tail  terminus  smooth,  with a characteristic 
indentation  observed  only  in  lateral  view.  Phasmids 
a t  44.4 f 1.60 (31.5-56) % of tail  length. 
M a l e s  : Not  found. 
TYPE HABITAT AND LOCALITY 
Soi1 around roots of grapevlne ( V i t i s  sp.), Wadl 
Dhulail, Jordan. 
TYPE SPECIMENS 
Collected by  the  author  in  August, 1981 and 
January, 1982. Holotype female and five paratype 
females a t  Rothamsted Experimental Station, Har- 
penden,  Hertfordshire,  England.  Five  paratype 
females a t  Commonwealth Institute of Parasitology, 
St. Albans, Hertfordshire, England. Four paratype 
females a t  Muséum national  d’Histoire  naturelle, 
Laboratoire des  Vers, Paris,  France. 
RELATIONSHIP 
Pralylenchus  jordanensis  n.  sp.  is  differentiated 
from  previously  described Pratylenchus species, 
except P. agilis Thorne & Malek;  1968, P. hexincisus  
Taylor & Jenkins, 1957, P. crassi Das & Sultana, 
1979 and P. scribneri Steiner, 1943, by  the absence 
of males,  empty  spermatheca of the female,  cephalic 
region  with  two  annules  and  slightly  offset  from the 
body,  short  stylet f < 18 Pm), V coefficient less than 
80,  undifferentiated  postlvulval  sac  (16.2  pm  in 
length)  and  smooth  tail  terminus. It differs from  the 
above-mentioned four species in the indentation of 
the tail terminus. It also differs from P. agilis (as 
described by  Thorne  and Malek, 1968)  in  its  shorter 
stylet (14.6 us. 17-18 pm)  and  apparently slower 
movements,  and  from P. hexincisus  (as described 
by  Taylor  and  Jenkins, 1957 and  Thorne  and Malek, 
1968) in having four incisures on the lateral field, 
often with additional oblique striae in the central 
band a t  mid-body  (six  incisures,  some of which 
are  irregularly  broken a t  mid-body,  in P. hexincisus) .  
P. jordanensis  n. sp. is also distinguished  from 
P. crassi by the shorter stylet (14.6 us. 17-18 Fm), 
Revue Nèmalol. 6 ( 2 )  : 187-192 (1983) 
Pratylenchus  jordanensis n. sp. 
B 
H 
Fig. 1. Pratylenchus jordanensis n. sp. (paratype females). A : anterior region ; B : whole specimen ; C : 
reproductive  system  (with  a  portion of the  intestinal fasciculi in  vulval  region) ; D : oesophageal  region ; 
E : part of lateral field at  mid-body ; F & G : tail  termini ; 13 : caudal region. 
Revue Nématol. 6 ( 2 )  : 187-192 (1983) 189 
Z. H a s h i m  
the  greater  distance  between  the  dorsal  oesophageal 
gland orifice and  stylet base (3.4 us. 2.1 Pm) and  the 
greater  number of tail  annules (21 us. 12-15). (Accord- 
ing  to Das and Sultana, 1979, P. crassi has a large 
oval  spermatheca filled with  spermatozoa ; however, 
this  structure was not  illustrated for this species and 
males were not. found.) P. jordanens is  n. sp. is also 
differentiated  from P. scribneri (as described by 
Sher and Allen, 1953, Thorne and Malek, 1968 and 
Roman  and  Hirschmann,  1969)  by  the  slightly  more 
conoid tail with a slight21y narrower terminus, the 
greater  distance  between  the  dorsal  oesophageal 
gland orifice and stylet base (3.4 us. 2.15 Pm, the 
latter according to Roman and Hirschmann, 1969) 
and Lhe inner  incisures fusinf distally on the tail 
(apparently not fusing on the tail in P. scribneri) .  
Eight.  specimens of P. scribneri from  the USA (Cali- 
fornia),  originally ident.ified by J. Roman, were made 
available  to  the  author  by  courtesy of D. J. Hooper. 
These differed from P. jordanens is  n.  sp.  in  the  broad- 
er tail terminus which is not indented, the lower cf 
coefficient (2.1 (2.0-2.3) us. 2.6 (2.1-3.0) ; n = 6)  and 
the absence of intestinal  fasciculi (l). The  lateral fields 
were  difficult to discern on  the  caudal region of these 
specimens of P. scribneri, so that  the  apparent differ- 
ence in  lateral field morphology  between  this species 
and P. jordanensis n.  sp.  (inner  incisures  fusing  in  this 
region in P. jordanensis but  not  in P. scribneri)  could 
not be confirmed.  Moreover, the difference in the 
position of the  dorsal  oesophageal  gland orifice 
between  the  two species is perhaps  too  small  to  be of 
diagnostic  value. 
Helicotylenchus microcephalus Sher, 1966 
(Fig. 2 A-F) . 
This species  was found  in  citrus  groves  in  the low- 
lying,  irrigated  areas of Jordan  where it was  reported 
as H .  cf. abunaamai  Siddiqi, 1972 (Hashim, 1979a). 
A critical  re-examination of twelve  specimens of 
these  populations  indicated  that  hey  belong  to 
H .  microcephalus because of a combination of the 
following characteristics : absence of males, sperm- 
athecae  devoid of spermatozoa,  cephalic  region 
truncate  in  most  specimens  and  invariably  with  four 
or five indistinct annules, stylet 22.3 f 0.11 (21.5- 
23.0) Fm long, stylet knobs with indented anterior 
surfaces, O coefficient (n  = 8) 33.6 f 1.04 (31-39.5), 
dorsally convex-conoid tail  with a  terminal  projection 
(l) The intestinal fasciculi of P .  jordanensis do not 
constitute a unique  character  within  the  genus Praty- 
Zenchus, 1 have  observed  similar  structures  in P. 
Goodeyi Sher & Allen, 1953 from  the  Canary  Islands. 
190 
of variable form and length and with, 6-12 annules 
of approximately uniform width, phasmids situated 
from three annules posterior to six annules anterior 
to  anal level and  lateral fields not areolated on tail 
and  with  their  inner incisures  normally  fusing  distally 
on  tail. 
A truncate cephalic  region is characteristic of 
H. mic~*ocephaZus (Sher,  1966),  but  this  was  not  always 
evident  in  the  populations  from  Jordan.  Instead, 
some  specimens  appeared  to  have a relatively 
rounded cephalic region (Fig. 2 A, B). A somewhat 
comparable variation was noted in populations of 
this species from  the  Fiji  Islands  in  which  the  cephalic 
region , although anteriorly flattened, had rounded 
sides in some specimens (Van den Berg & Kirby, 
1979). 
The  tail of H .  microcephalus t>ypically has a  distinct 
ventral projection, with a pointed or hemispheroid 
tip (Sher, 1966). However, the form and length of 
t.his projection Vary  considerably  between  populations 
(Van den Berg & Heyns, 1975 ; Ali, 1976 ; yan  den 
Berg,  1978 ; Van  den  Berg & Kirby,  1979).  The 
Jordanian populations of this species most,ly exhib- 
ited a relatively short tail projection (less than   the  
width of two annules) with a rounded tip ; in some 
specimens it was  almost  indistinguishable. 
H .  mangiferensis Elmiligy, 1970 was synonymized 
with H.  microcephalus by Ali (1976), but  Anderson 
(1979)  reinstated it as a valid species. The latter 
action  appears tlo  be justified  as  the  consistently 
indistinct,  cephalic  annulation of H. microcephalus 
contrasts  trongly  with  the  distinctly  annulated 
cephalic  region of W. mangiferensis,  and  the O coeffi- 
cient is greater  in  the  former species than  in  the labter 
(32-45 us. 21-25, according to  Sher, 1966, and Elmi- 
ligy, 1970, respectively). 
Tylenchorhynchus clarus Allen, 1955 
(Fig. 2 G-K) 
T.  clarus was originally described with anteriorly 
directed stylet knobs (Allen, 1955). Specimens from 
Egypt  had  flattened  to  anteriorly  directed  ones 
(Elmiligy, 1969). In contrast, T. clarus from Jordan 
had  laterally  to  posteriorly  inclined  stylet  knobs 
(Fig. 2 H-J),  except  one  population  from  the  Jubeiha 
area  which possessed anteriorly  directed  lmobs. 
Although  differently  illustrated by Elmiligy  (1969), 
the spicules of male T.  clarus have distinct ventral 
flanges at  their  distal  ends,  and  the  gubernaculum  is 
protrusible  through  the cloaca. Such  features  are 
characteristic of the subfamily Tylenchorhynchinae 
Eliava, 1964 (Siddiqi, 1971). 
Revue  NSmatol. 6 (2 )  : 187-192 (1983) 
Pratylenchus  jordanensis 11. sp.  
Fig. 2 .  Helicotylenchus microcephalus Sher, 1966. Female. A : anterior region ; B : cephalic region ; C-F : 
caudal regions. Tylenchorhynchus  clarus Allen.  1955. Female. G-J : stylets. Male. K : caudal region. Tylen-  
chorlzyrzchus' goffarti Sturhan, 1966. Male. L : cloaca1 region. 
Tylenchorhynchus goffarti Sturhan, 1966 gubernaculum  shape  in  the  original  description  was 
Note  that a few specimens  identified  as T.  dubius 
(Bütschli,  1873)  Filipjev, 1936 by Hashim (1979~) 
The  gubernaculum of male T.  goffarti typically  were  re-examined  and  found to  belong to  T.  goffarfi. 
has a  slight  proximal  curvature  (Sturhan,  1966). It is  possible tha t  al1 previous  records of T.  dubius 
However, in a population of this species from  Jubeiha,  in  Jordan  (Bridge,  1978 ; Hashim, 1979a & b) pertain 
the  gubernaculum  was siclrle-shaped (Fig. 2 L). The  to T .  goffarti. 
(Fig. 2 L) observed  in mal s  from  other parts of the  country. 
Revue Nimatol. 6 ( 2 )  : 187-192 (1983) 191 
Z. Hashim 
ACKNOWLEDGEMENTS 
The  author wishes to  thank D. J. Hooper of Roth- 
amsted  Experimental  Station,  England,  for  providing 
specimens of Pratylenchus scribneri, and to P. A. A. 
Loof of Landbouwhogeschool,  Wageningen, the 
Netherlands, and R. Fortuner of California Dept. of 
Food & Agriculture, USA, for their useful criticism of 
this  manuscript. 
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Accepté pour publication le 29 juillet 1982. 
192 Revue  Némaiol. 6 (2) : 187-192 (1983) 


Description of Pratylenchus jordanensis n. sp. (Nematoda : Tylenchida) and notes on other Tylenchida from Jordan

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