Comparative Parasitology 67(1) 2000 - Peru State College

strictive traits that were basically descriptive of
specific features of P. umbellatus. These included
the number of proboscis hooks, collar and
trunk spines, and giant nuclei of the cement
gland, as well as the extent of distribution of the
trunk spines, and the position of the testes.
These same traits were used by subsequent
workers, e.g., Petrochenko (1956) and Yamaguti
(1963), despite the addition of more species adding
more variability to the diagnostic criteria of
the genus over the years. A new diagnosis of the
genus Pallisentis is provided below.
Pallisentis Van Cleave, 1928, sensu lato
DIAGNOSIS: Quadrigyridae, Pallisentinae.
Trunk slender, small-medium in length, with an
anterior set of collar spines and a posterior set
of trunk spines separated by region lacking
spines. Collar spines arranged in a few closely
set circles; circles of trunk spines more widely
spaced and may extend to posterior end of males
or females. Giant hypodermal nuclei may be
present. Proboscis short, cylindroid-spheroid
with 4 circles of 6-12 hooks each. Proboscis receptacle
single-walled, with large cerebral ganglion
near its base. Lemnisci long, cylindrical,
equal or unequal. Testes ovoid-cylindrical, contiguous.
Cement gland syncytial, medium-long,
with few to many giant nuclei. Cement reservoir
present. Saefftigen's pouch present or absent.
Parasites of freshwater fishes in Asia.
The Subgenera of Pallisentis
Based on the number of hooks in each of the
proboscis hook circles, Golvan (1959) erected 3
subgenera of Pallisentis: Farzandia Thapar,
1931, with 10 hooks per circle, Neosentis Van
Cleave, 1928, with 8 hooks per circle, and Pallisentis
Van Cleave, 1928, with 6 hooks per circle.
Some species were not assigned to a subgenus,
and others could be relegated to more
than 1 subgenus or not to any. By 1994 a greater
number of species had been described and the
number of nonassignments and exceptions increased
disproportionately. Golvan (1994) additionally
did not include 4 other species described
earlier (footnote, Table 1). The character (number
of hooks per circle) used by Golvan (1959)
is inconsistent and showed variations even within
the same species and, thus, should not be used
for subgeneric assignment of species. Yamaguti
(1963), Tadros (1966), Gupta and Verma (1980),
Soota and Bhattacharya (1982), Gupta and Fat-
AMIN ET AL.—REVISION OF THE GENUS PALLISENTIS 41
ma (1986), and Chowhan et al. (1987) also rejected
Golvan's (1959) system. Tadros (1966)
and Soota and Bhattacharya (1982) also agreed
with the above authors and evaluated other taxonomic
characters of Pallisentis. We found the
most consistent character to be the difference in
the size of proboscis hooks in subsequent circles.
Other characters of considerable consistency
included the size of the cement gland and the
number of its giant nuclei, the shape and distribution
of trunk spines, and the presence or absence
of Saefftigen's pouch. Based on the first 3
characters listed above, we designate herein 3
new subgenera. All characters (above) are used
to construct the subsequent key to species.
Demidueterospinus subgen. n.
DIAGNOSIS: With the characters of the genus
Pallisentis provided herein. Proboscis hooks in
circle 2 about half as long as hooks in circle 1.
Cement gland usually small, with few giant nuclei.
Taxonomic summary
TYPE SPECIES: Pallisentis (D.) ophiocephali
(Thapar, 1931) Baylis, 1933.
OTHER SPECIES: Pallisentis (£>.) basiri Farooqi,
1958; Pallisentis (£>.) panadei Rai, 1967.
Remarks
Pallisentis basiri and P. panadei were synonymized
with Pallisentis colisai Sarkar, 1954,
by Soota and Bhattacharya (1982). We consider
these species to be valid. These and other synonymies
made by Soota and Bhattacharya
(1982) did not acknowledge the species-specific
differences that we outline in our key. Further,
their tabulated data often did not match the narrative
and were occasionally misplaced. These
synonymies were also not accepted by Khan and
Bilqees (1987) and were not followed by other
workers. The redescription of P. basiri by Gupta
and Fatma (1986) is inconsistent with the characteristics
of that species and appears to be of
another species. Pallisentis ophiocephali of Moravec
and Sey (1989) from Vietnam is conspecific
with our material from the same location
and is described herein as a new species.
Brevitritospinus subgen. n.
DIAGNOSIS: With the characters of the genus
Pallisentis provided herein. Proboscis hooks in
circle 3 about half as long as hooks in circle 2.
Copyright © 2011, The Helminthological Society of Washington