Comparative Parasitology 67(1) 2000 - Peru State College

78 COMPARATIVE PARASITOLOGY, 67(1), JANUARY 2000
(proximal subunit expanded); 8) a sinistral vaginal
aperture; and 9) absence of eyes. Of dactylogyrid
genera with members infecting freshwater
siluriforms in the Neotropics, characters
defining Ameloblastella suggest a relationship
with Vancleaveus Kritsky, Thatcher, and Boeger,
1986, and Philocorydoras Suriano, 1986. Members
of these 3 genera share the characteristics
of possessing overlapping gonads (testis dorsal
to germarium), a ventral bar with a medial process,
hook shanks comprised of 2 subunits
(proximal subunit expanded), subspherical eye
granules, and a dilation of the vas deferens to
form the seminal vesicle. Ameloblastella differs
from both Vancleaveus and Philocotydoras by
the position of the vaginal aperture (ventral in
Vancleaveus and Philocorydoras). It further differs
from Philocorydoras by lacking eyes and
having a coiled male copulatory organ (male
copulatory organ an arced tube in Philocorydoras)',
and from Vancleaveus by the absence of a
basal fold on the superficial root of the dorsal
anchor and an expanded distal subunit of the
hook shank (both present in Vancleaveus) (see
Kritsky et al., 1986; Suriano, 1986b).
Of the 22 species of Urocleidoides considered
incertae sedis by Kritsky et al. (1986), 2 of them
are transferred to Ameloblastella as A. chavarriai
(Price, 1938) comb. n. and A. mamaevi
(Kritsky and Thatcher, 1976) comb. n. While A.
chavarriai is the type species of Ameloblastella
and defines the genus, A. mamaevi possesses all
diagnostic features of Ameloblastella (see Kritsky
and Thatcher, 1976).
Suriano and Incorvaia (1995) described Vancleaveus
platensis from the gills of the pimelodid,
P. c. maculatus. This helminth is not a member
of Vancleaveus because of the absence of
basal folds on the superficial root of the dorsal
anchor and the presence of a sinistral vaginal
aperture (vaginal pore ventral in Vancleaveus
spp.). The original description of the species indicates
that it possesses all of the diagnostic features
of Ameloblastella, except for the presence
of a nonarticulated male copulatory organ and
accessory piece. However, specimens of this
species in the senior author's collection and collected
from Pimelodus clarias (Lacepede) from
the Rio de la Plata, Argentina, show a delicate
articulation process attaching the base of the
male copulatory organ to the accessory piece.
The latter finding supports the transfer of V. platensis
to Ameloblastella.
Copyright © 2011, The Helminthological Society of Washington
Ameloblastella chavarriai (Price, 1938)
comb. n.
(Figs. 1-9)
REDESCRIPTION: Body 596 (408-742; n =
30) long; greatest width 113 (92-134; n = 33)
usually in posterior trunk. Cephalic lobes poorly
to moderately developed. Accessory eye granules
in cephalic, anterior trunk regions. Pharynx
ovate, 27 (24-30; n = 33) in greatest width;
esophagus short to moderately long. Peduncle
contracted, broad (ambient temperature formalin
fixation) or elongate, narrow (hot formalin fixation);
haptor subhexagonal, 84 (69-108; n =
28) wide, 72 (60-88; n = 29) long. Ventral anchor
33 (30-36; n = 22) long, with elongate
superficial root, short deep root, slightly curved
shaft, straight point; base 19 (16-21; n = 16)
wide. Dorsal anchor 27 (23—31; n = 16) long,
with well-developed roots, slightly curved shaft,
elongate straight point; deep root protruding
posteriorly from anchor base; anchor base 18
(17-20; n = 10) wide. Ventral bar 33 (29-37;
n = 22) long, yoke-shaped, with posteromedial
process usually bent anteriorly dorsal to bar.
Dorsal bar 30 (26-34; n = 20) long, broadly Vshaped,
with slightly enlarged ends. Hook with
protruding truncate thumb, delicate point; hook
24 (20-27; n = 36) long; filamentous booklet
(FH) loop extending to level of union of shank
subunits. Male copulatory organ 141 (128-158;
n = 8) long, a coil of about 2.5 rings; diameter
of proximal ring 17 (15-20; n = 20); base of
male copulatory organ with small sclerotized
plate. Accessory piece 32 (27—38; n = 26) long,
25 (22—32; n — 22) wide, comprising 2 subunits;
dextral subunit terminally acute, subtriangular,
with expanded lateral margins; sinistral subunit
L-shaped with flared termination, serving as
guide for male copulatory organ. Testis elongate,
fusiform (lateral margins indistinct); seminal
vesicle large, fusiform, lying diagonally in median
field of anterior trunk posterior to male copulatory
organ; prostatic reservoir lying to right
of seminal vesicle and body midline, posterior
to male copulatory organ. Germarium an inverted
elongate cone, 119 (84-166; n = 20) long,
35 (27—53; n = 21) wide; oviduct, ootype not
observed; uterus delicate, infrequently with single
egg; vagina a sclerotized tube; vaginal aperture
on sclerotized papilla lying in small indentation
of body margin; seminal receptacle