Type Habitat and Locality
Soil around roots of grapevine (Vitis sp.), Wadi Dhulail, Jordan.
Type Specimens
Collected by the author in August, 1981 and January, 1982.
Holotype female and five paratype females at Rothamsted Experimental Station,
Harpenden, Hertfordshire, England. Five paratype females at Commonwealth
Institute of Parasitology, females at Muséum national d’Histoire
naturelle, Laboratoire des Vers, Paris, France.
Relationship
Pratylenchus 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 (<
18 um), V coefficient less than 80, undifferentiated post-vulval
sac (16.2 um 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 & Malek,
1968) in its shorter stylet (14.6 vs. 17.8 um) and apparently slower
movements, and from P. hexincisus (as described by Taylor &
Jenkins, 1957 and Thorne & Malek, 1968) in having four incisures on
the lateral field, often with additional oblique striae in the central
band at mid-body (six incisures, some of which are irregularly broken at
mid-body, in P. hexincisus). P. jordanensis n. sp.
is also distinguished from P. crassi by the shorter stylet (14.6
vs. 17-18 um), the greater distance between the dorsal oesophageal
gland orifice and stylet base (3.4 vs. 2.1 um) and the greater number
of tail annules (21 vs. 12-15). (According 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. jordanensis 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 slightly narrower terminus, the greater distance between the dorsal oesophageal
gland orifice and stylet base (3.4 vs. 2.15 um, the latter according
to Roman and Hirschmann, 1969) and the inner incisures fused distally on
the tail (apparently not fusing on the tail in P. scribneri).
Eight specimens of P. scribneri from the USA (California), originally
identified by J. Roman, were made available to the author by courtesy of
D.J. Hooper. These differed from P. jordanensis n. sp. in
the broader tail terminus which is not indented, the lower c’ coefficient
(2.1 (2.0-2.3) vs. 2.6 (2.1-3.0); n = 6) and the absence of intestinal
fasciculi (1). The lateral fields were difficult
to discern on the caudal region of these specimens of P. scribneri,
so that the apparent difference in lateral field morphology between these
species and P. jordanensis n. sp. (inner incisures fusing in this
region in P. jordanensis but not 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.
(1) The intestinal fascuculi of P.
jordanensis do not constitute a unique character within the genus Pratylenchus,
I have observed similar structures in P. goodeyi Sher & Allen,
1953 from the Canary Islands.