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Redescription of Pseudogilquinia pillersi (Southwell, 1929)
(Cestoda, Trypanorhyncha) from serranid and lethrinid fishes
from New Caledonia and Australia
Ian Beveridge
1*
, Claude Chauvet
2
and Jean-Lou Justine
3
1
Department of Veterinary Science, University of Melbourne, Veterinary Clinical Centre, Werribee, 3030, Victoria, Australia;
2
Laboratoire d’
Études des Ressources Vivantes et de l’Environnement Marin, Université de Nouvelle Calédonie, BP R4, 98847 Nouméa
Cedex, Nouvelle-Calédonie;
3
Équipe Biogéographie Marine Tropicale, Unité Systématique, Adaptation, Évolution
(CNRS, UPMC, MNHN, IRD), Institut de Recherche pour le Développement, BP A5, 98848 Nouméa Cedex, Nouvelle-Calédonie
*
Corresponding author: ibeve@unimelb.edu.au
Introduction
Many species of trypanorhynch cestodes described from fish-
es from Sri Lanka (Ceylon) and southern India in the early
1900s are still poorly known (Beveridge et Campbell, 1998).
In a re-examination of the remaining collections of authors
such as A. Shipley, J. Hornell and T. Southwell, Beveridge and
Campbell (1998) redescribed several species and allocated
them to currently recognised genera. One of these was Tenta-
cularia pillersi, described from plerocerci collected from
a number of species of teleost fish by Southwell (1929) off
the coast of Sri Lanka. Although their redescription was in-
complete, limited by the quality of the material available, Bev-
eridge and Campbell (1998) placed the species in the genus
Dasyrhynchus Pintner, 1928 following Reimer (1984) who
reported new specimens from Saurida undosquamis (Rich-
ardson, 1848) (Synodontidae) and Psettodes erumei (Bloch et
Schneider, 1801) (Psettodidae) from Mozambique, but did
not provided a detailed redescription. Most recently, Palm
(2004) has allocated the species to the genus Pseudogilquinia
Bilquees et Khartoon, 1980. Since the precise taxonomic posi-
tion of this cestode appears to be uncertain, the opportunity is
Skóra
Stefañski
DOI: 10.2478/s11686-007-0029-9
© 2007 W. Stefañski Institute of Parasitology, PAS
Acta Parasitologica, 2007, 52(3), 213–218; ISSN 1230-2821
Abstract
Pseudogilquinia pillersi (Southwell, 1929), a poorly known species of trypanorhynch, is redescribed from plerocerci collect-
ed from Epinephelus coioides (Hamilton, 1922), Epinephelus malabaricus (Bloch et Schneider, 1801) (Serranidae) and
Plectropomus laevis (LacépPde, 1801) (Serranidae) off New Caledonia. These were compared with specimens from Lethrinus
atkinsoni Seale, 1910 and Lethrinus miniatus (Forster, 1801) (Lethrinidae) off the north-east coast of Australia as well as syn-
types from Protonibea diacantha (LacépPde, 1802) from Sri Lanka. Although size differences were found in parts of the scolex
as well as in the sizes of the tentacular hooks, the hook arrangements were identical in all specimens. The differences observed
were attributed provisionally to intra-specific variation across a wide geographic and host range.
Résumé
Une espPce de trypanorhynque peu connue, Pseudogilquinia pillersi (Southwell, 1929), est redécrite B partir de plérocerques
récoltés chez Epinephelus coioides (Hamilton, 1922), Epinephelus malabaricus (Bloch et Schneider, 1801) et Plectropomus
laevis (LacépPde, 1801) (Serranidae) en Nouvelle-Calédonie, et chez Lethrinus atkinsoni Seale, 1910 et Lethrinus miniatus
(Forster, 1801) (Lethrinidae) de la c^te nord-est de l’Australie, et des syntypes provenant de Protonibea diacantha (LacépPde,
1802) du Sri Lanka. En dépit de la taille différente des constituants du scolex et des crochets des tentacules, l’arrangement des
crochets était similaire chez tous les spécimens. Les différences observées ont été provisoirement attribuées B une variation
intraspécifique dans une aire géographique étendue et un grande variété d’h^tes.
Key words
Cestoda, Trypanorhyncha, Pseudogilquinia pillersi, redescription, fishes, New Caledonia, Australia
Ian Beveridge et al.
taken here of redescribing the species based on new material
collected in New Caledonia and comparing this material with
specimens from Australia as well as with syntypes.
Materials and methods
Plerocerci collected from fish were dissected free from blas-
tocysts, were flattened or shaken in hot (60°C) saline to ensure
that the tentacles were everted and were fixed in 70% ethanol.
They were stained in either carmine or celestine blue, dehy-
drated in ethanol, cleared in clove oil or methyl salicylate and
mounted in Canada balsam. Individual tentacles were sepa-
rated from scoleces with a scalpel blade, mounted individual-
ly in balsam and manipulated to display specific surfaces of
the tentacle. Drawings were made with drawing tube attached
to an Olympus BH microscope. All illustrations have been
made from specimens from Epinephelus coioides. Measure-
ments are given in micrometres unless otherwise indicated as
the range followed by the mean and the number of specimens
measured (n) in parentheses. Some specimens were prepared
for scanning electron microscopy by dehydrating in ethanol
and allowing to dry following transfer to hexamethyldisil-
asane (Pro Sci Tech, Townsville, Australia). They were then
coated with gold and examined using a Phillips 505 SEM at an
accelerating voltage of 10–20 kV. Terminology for the mor-
phological features of trypanorhynch cestodes follows Camp-
bell and Beveridge (1994) and Jones et al. (2004). Specimens
were deposited in the Muséum National d’Histoire Naturelle,
Paris (MNHN) or the Natural History Museum, London
(BMNH).
Results
Pseudogilquinia pillersi (Southwell, 1929) Palm, 2004
Synonyms: Tentacularia pillersi Southwell, 1929; Dasyrhynchus
pillersi (Southwell, 1929) Reimer, 1984.
Material examined: syntype from Protonibea diacantha
(LacépPde, 1802), Sri Lanka (BMNH 1997.10.18.148-155);
1 specimen from body cavity of Lethrinus atkinsoni Seale,
1910, Heron Island, Queensland, Australia (BMNH 2004.3.
18.98-99); 1 specimen from body cavity of Lethrinus minia-
tus (Forster, 1801) (= L. chrysostomus Richardson, 1848, label
name), Heron Island, Queensland, Australia (BMNH 2004.3.
18.97); 15 specimens from body cavity of Epinephelus coioi-
des (Hamilton, 1922), between Ilôt Goëland and Ilôt Maître,
off Nouméa, New Caledonia (22°31´S, 166°24´E), 13.v.2005,
MNHN JNC 1535; 11 specimens from body cavity of Epine-
phelus malabaricus (Bloch et Schneider, 1801), off Ouen Toro,
Nouméa, New Caledonia (22°19´S,166°27´E), 18.v.2005,
MNHN JNC 1536; 17 specimens from Plectropomus laevis
(LacépPde, 1801), Récif Aboré, off Nouméa, New Caledonia
(22°20′S, 166°15′E), 2.vi.2006, MNHN JNC 1887; 1 speci-
men from P. laevis, Fausse Passe de Uitoé, external slope, off
Nouméa, New Caledonia (22°12´S, 166°7´E), 11.vi.2006,
MNHN JNC 1865.
Redescription
Based on specimens from New Caledonia; measurements from
5 specimens each from Epinephelus coioides, E. malabaricus
and Plectropomus laevis. Measurements of specimen from
Lethrinus miniatus also provided.
Scolex craspedote, 6.1–12.0 (8.03, n = 15) mm long, maxi-
mum width in region of pars bulbosa 1.17–2.52 (1.94, n = 15)
mm. Bothria generally wider than long, with indistinct margin
but with distinct notch in posterior border (Fig. 1); pars both-
rialis 320–500 (418, n = 15) long, bothrial width 500–1030
(655, n = 15) bothrial groove prominent; microtriches of ad-
herent surface of bothrium multidigitate with 3–5 elongate,
terminal projections (Fig. 13). Pars vaginalis 3.50–7.30 (5.29,
n = 15) mm long; sheaths straight in anterior part of scolex,
sinuous in posterior part. Bulbs elongate, 2.02–2.63 (2.45,
n = 10) mm long, width 230–350 (289, n = 15), bulb ratio
7.06–10.19 (8.40, n = 15); bulbs extend into appendix; retrac-
tor originates near anterior extremity of bulb (Fig. 8), band of
nuclei present from site of attachment of retractor to posteri-
or extremity of bulb. Scolex ratio (mean): 1:23.3:5.8. Based
on incompletely everted tentacles, longest tentacle 1.65 mm;
tentacles slightly bulbous at base, diameter at base 110–150
(135, n = 10), diameter in metabasal region 130–150 (146, n
= 10). Metabasal armature heteroacanthous, heteromorphous;
hooks hollow; in metabasal region, space present between
hook files 1 and 1' (Fig. 3); rows begin on internal surface, ter-
minate on external surface (Fig. 2). Hooks 1(1’) uncinate,
113–130 (122, n = 10) long, base 88–125 (109, n = 10) long;
hooks 2(2') with more slender blade, shorter base, 88–115
(103, n = 10) long, base 55–80 (66, n = 10) long; hooks 3(3')
slender, falcate, 93–115 (102, n = 10) long, base elongate,
38–48 (43, n = 10) long; hooks 4(4') slender, falcate, 80–108
(95, n = 10) long, base 35–45 (41, n = 10) long; hooks 5(5')
slender, falcate, 80–100 (92, n = 10) long, base 30–38 (33, n
= 10) long; hooks 6(6') slender, falcate, 75–95 (80, n = 10)
long, base 15–33 (26, n = 10) long; hooks 7(7') slender, fal-
cate, 70–85 (78, n = 10) long, base 15–25 (21, n = 10) long;
hooks 8(8') slender, 55–70 (68, n = 10) long, base 13–20 (17,
n = 10) long. Intercalary hooks arranged in 2–3 (usually 2)
rows; first row of 4–5 hooks, commencing posterior to hooks
5(5'), 25–43 (34, n = 5) long, base 8–10 (9, n = 5) long; second
row of 3–4 intercalary hooks, hooks smaller than in first row,
23–30 (25, n = 5) long, base 4–8 (5, n = 5) long; additional
row, if present, extending beyond principal row of hooks (Fig.
4). Band of hooks in middle of external surface, arranged as
central hook and 2 flanking hooks, as long as intercalary
hooks but with much longer base, 23–35 (32, n = 5) long, base
11–18 (15, n = 5) long (Fig. 4).
Basal armature: axis of basal armature initially bothrial-
antibothrial, gradually becoming internal-external (Figs 6 and
10); at base, hook rows begin on bothrial surface of tentacle;
first row of hooks on bothrial surface tiny, elongate with en-
214
Œl¹ski
Redescription of Pseudogilquinia pillersi from serranid and lethrinid fishes
215
Stanis³a
Figs 1–8. Pseudogilquinia pillersi (Southwell, 1929). Specimens from Epinephelus coioides. 1. Scolex. 2. Metabasal armature of tentacle,
bothrial surface. 3. Metabasal armature of tentacle, internal surface. 4. Metabasal armature of tentacle, external surface. 5. Basal armature
of tentacle, internal surface on left-hand. 6. Basal armature of tentacle, internal surface; the dotted line indicates the shift in the orientation
of the armature. 7. Basal armature of tentacle, antibothrial surface, internal surface on right-hand side. 8. Anterior end of bulb showing attach-
ment of retractor muscle and band of nuclei continuing posteriorly from point of attachment. Scale-bars = 0.1 mm
Ian Beveridge et al.
216
Roborzyñski
rosbœŸæv
fjad kadsææ¿æ
Figs 9–13. Pseudogilquinia pillersi (Southwell, 1929), scanning electron micrographs; specimens from Epinephelus coioides. 9. Bothrium
and everted tentacles. 10. Basal armature, bothrial surface. 11. Metabasal armature, bothrial surface. 12. Metabasal armature, external surface.
13. Bothrial groove and microtriches. Scale-bars = 0.1 mm
Redescription of Pseudogilquinia pillersi from serranid and lethrinid fishes
larged, ovoid tips; on antibothrial surface, whole basal region
covered with similar hooks in apparently irregular arrays (Fig.
6); rows 2–3 of hooks on bothrial surface uncinate, decreasing
in size around internal and external surfaces of tentacle; rows
4–7 forming array of enlarged hooks, diminishing in size ante-
riorly as well as internally and externally, hooks 28–65 (50,
n = 5) long, base 18–40 (26, n = 5) long, anterior to array of
large hooks, rows of slender, spiniform hooks commence,
gradually merging into principal rows of metabasal armature;
on antibothrial surface of base, prominent tightly-packed ar-
ray of small spiniform hook 5–15 (10, n = 5) long; approxi-
mately 12 hooks in length and 12 hooks across array (Fig. 7);
immediately anterior to array, area with tiny spiniform hooks
on antibothrial surface before principal rows begin.
Specimen from L. miniatus: 4.4 mm long, maximum
width in region of pars bulbosa 810, pars bothrialis 230, both-
rial width 320, pars vaginalis 3.4 mm, bulb 1050 long, 170
wide.
Discussion
The specimens described here closely resemble P. pillersi
in the features of the scolex, the small bothria and elongate
bulbs, in the metabasal armature with eight hooks in each
principal row, with two to three rows of intercalary hooks and
with a slender band of very slightly enlarged hooks in the
middle of the external surface of the tentacle. The basal arma-
ture also resembles that of P. pillersi with the area of tiny
hooks with lobed tips at the very base and the compact array
of spiniform hooks. However, the basal armature of P. piller-
si is incompletely described (Beveridge and Campbell 1998),
being based on a series of syntype specimens, none of which
provided all views of the basal armature. Re-examination of
one of these (BMNH 1977.10.18.148-155) confirmed that the
enlarged hooks on the internal surface at the base of the ten-
tacle describe above are present in the type material but are
not clearly visible and could not be illustrated.
Beveridge and Campbell (1998) described the arrange-
ment of hooks on the external surface of the tentacle as a cen-
tral chainette, with each chainette element flanked by a small-
er pair of hooks. In the current specimens from New Caledo-
nia, the arrangement is similar, but there is no difference in the
length of the hooks, even though they are distinguishable from
the intercalary rows. Although this distinction is not evident in
the scanning electron micrographs, as only the hook tips are
visible, the principal difference is in the sizes of the hook
bases, which are longer in the hooks of the central files (11–
15) compared with the intercalary hooks (8–10). There is also
some variation within the new material from New Caledonia,
with the differences between the central files of hooks on the
external surface of the tentacle and the intercalary rows of
hooks being more pronounced in some specimens than in oth-
ers. This variation is not related to the host species from which
the specimens originated. In the Australian specimens, there is
no obvious difference in the size of the central hooks on the
external surface of the tentacle.
The specimens described here from New Caledonia and
Australia also differ in size from the type series. Scolex length
in the specimens described here from New Caledonia was
smaller (6.1–12.0 mm) than in the types (10.1–14.7 mm) as
were the bulbs (2.02–2.63 mm in the specimens described
here compared with 3.0–5.5 mm in the types). The scolex
ratios of the two sets of specimens were 1:23:5.8 for the spec-
imens described from New Caledonia, compared with 1:14:7.5
in the types. The principal difference lies in the ratio of the
pars bothrialis to the pars vaginalis, with the latter greatly de-
pendent upon the degree of relaxation of the specimen. The
specimen from Lethrinus miniatus from Australia was even
smaller with a total length of 4.35 mm. In addition, the sizes of
hooks in the principal rows were smaller in the specimens
described here (hooks 1,1' 113–130 long in specimens from
New Caledonia, 60–113 long in specimens from Australia and
173–198 in the syntypes). In spite of these differences, every
other feature including hook shape was identical between the
types and the specimens from Australia and New Caledonia.
The specimens described here from New Caledonia and
Australia may therefore represent new species, very similar to
P. pillersi or may belong to this species. Given the limited in-
formation on variability within the species, a conservative ap-
proach has been adopted and the specimens have been refer-
red tentatively to P. pillersi. In spite of collections from sig-
nificant numbers of elasmobranchs from New Caledonia and
the Great Barrier Reef, Australia, adults of this species have
not been found. The characteristics of the adults may provide
insights into whether the cestodes described here represent a
single variable species or several very closely related spe-
cies. Similarly, nucleotide sequences may provide such evi-
dence in the future, but are not available currently.
A feature noted in the current redescription was a shift in
orientation of the basal armature, with an initial orientation
from bothrial-antibothrial to internal-external in the meta-
basal region. The syntype material is not adequate to deter-
mine whether this character also exists in the original speci-
mens. A similar shift in orientation, but from internal-exter-
nal to bothrial-antibothrial has been reported in the eutetra-
rhynchoid genus Hemionchos Campbell et Beveridge, 2006
from species of Mobula from the Gulf of California, Mexico
(Campbell and Beveridge 2006). Although not described as
such, examination of illustrations of Dasyrhynchus pacificus
Robinson, 1959 (see Beveridge and Campbell 1993, fig. 3)
and D. talismani Dollfus, 1935 (see Beveridge and Campbell
1993, fig. 17) suggests that the same phenomenon may occur
in the related genus Dasyrhynchus Pintner, 1928.
Palm (2004) distinguished Dasyrhynchus from Pseudogil-
quinia and placed the latter in the subfamily Grillotiinae Doll-
fus, 1942, closely aligned to Dasyrhynchus. Both genera were
characterised (Palm 2004, p. 255) as having a craspedote
scolex with a distinct pars proliferans scolecis and a poe-
ciloacanthous armature, that is with a chainette. Dasyrchyn-
217
Ian Beveridge et al.
chus was differentiated from Pseudogilquinia on the basis that
Dasyrhynchus had cordiform bothria, bulbs not extending into
the pars proliferans scolecis and a characteristic basal arma-
ture without a trapezoidal array of small hooks while Pseu-
dogilquinia had collar-like bothria, the bulbs extended into the
pars proliferans scolecis and the trapezoidal array of hooks
was absent. In addition, Dasyrhynchus had longer bulbs. The
current redescription of P. pillersi conforms with some of
these distinctions. The species is craspedote and the bulbs
project into the pars proliferans scolecis; in addition, the bulb
ratio 7.06–10.19 (8.4) is generally (though not invariably)
smaller than species of Dasyrhynchus (9.3–19.0) and the pars
bothrialis is extremely short. However a compact array of
hooks is present at the base of the tentacle as it is in P. micro-
bothria (MacCallum, 1917) rendering this differential char-
acter dubious. The principal differentiating character, the pres-
ence of a chainette, becomes more difficult as, in the present
redescription, the identification of the central files of hooks on
the external surface of the tentacle as a chainette is quite sub-
tle. Using the key provided by Palm (2004, p. 255), the species
could also be allocated to Pseudogrillotia Dollfus, 1969.
The above comments suggest that the definition of genera
within this subfamily warrants additional attention and that
detailed redescriptions of poorly understood species such as
P. pillersi may eventually lead to a more robust classification
of the Grillotiinae.
Pseudogilquinia pillersi was found only in large species
of epinephelines in New Caledonia. Numerous specimens of
smaller epinepheline species (E. fasciatus, E. maculatus, E.
merra) have been examined by one of us (J.-L. J) and none has
been found infected with P. pillersi. It is possible that, since
the parasite occurs primarily in large predatory fish, that there
may an earlier larval stage in smaller fishes.
(Accepted May 21, 2007)
Acknowledgements. Students involved in fishing operations and the
collection of parasites in New Caledonia were Amandine Marie,
Damien Hinsinger, Aude Sigura and Géraldine Colli; Prof. Pierre
Legendre (Université de Montréal, Canada) also assisted in the
examination of fishes. Soazig Le Mouellic (UNC) and Angelo di
Matteo (IRD) provided technical help. We wish to thank Eileen
Harris for the loan of specimens from BMNH and Joan Clarke for the
scanning electron micrographs.
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