sphyraena qenie klunzinger (sphyraenidae) off new...
TRANSCRIPT
Anisakid nematodes (Nematoda: Anisakidae)from the marine fishes Plectropomus laevis Lacepede(Serranidae) and Sphyraena qenie Klunzinger(Sphyraenidae) off New Caledonia, including two newspecies of Hysterothylacium Ward & Magath, 1917
Frantisek Moravec . Jean-Lou Justine
Received: 26 June 2015 / Accepted: 2 August 2015
� Springer Science+Business Media Dordrecht 2015
Abstract Based on light and scanning electron
microscopical studies, two new species ofHysterothy-
lacium Ward & Magath, 1917 (Nematoda: Anisaki-
dae) are described from the digestive tract of
perciform fishes off New Caledonia: H. alatum n. sp.
from Plectropomus laevis (Lacepede) (Serranidae)
and H. sphyraenae n. sp. from Sphyraena qenie
Klunzinger (Sphyraenidae). The former species
(H. alatum) is mainly characterised by its large body
(male 42.05 mm, gravid females 51.18–87.38 mm
long), the shape of the dorsal lip, conspicuously broad
cervical alae, a short caecum and a long ventricular
appendix, the length of the spicules (925 lm), the
number (25 pairs) and distribution of the genital
papillae and the tail tip bearing numerous minute
cuticular protuberances. The other species
(H. sphyraenae) is mainly characterised by the
presence of narrow lateral alae, a short caecum and a
long ventricular appendix, the length (762–830 lm)
and shape of the spicules, the number (37–38 pairs)
and arrangement of the genital papillae, and by the tail
tip which lacks any distinct cuticular projections
visible under the light microscope. In addition, and
unidentifiable at the species level, conspicuously large
(45.71–66.10 mm long) larvae of Contracaecum
Railliet & Henry, 1912, were found in the body cavity
of P. laevis, which serves as a paratenic host for this
parasite.
Introduction
Our knowledge of the species diversity of anisakid
nematodes (Anisakidae) which parasitise marine
fishes and elasmobranchs in New Caledonian waters
remains incomplete, since only four nominal species
of these parasites have previously been recorded in
this region: Terranova scoliodontis (Baylis, 1931)
from the shark Galeocerdo cuvier (Peron & Lesueur)
(Carcharhinidae),Hysterothylacium cenaticum (Bruce
& Cannon, 1989) from Tetrapturus audax (Philippi)
(Istiophoridae), Raphidascaris (Ichthyascaris) ne-
mipteri Moravec & Justine, 2005 from Nemipterus
furcosus (Valenciennes) (Nemipteridae), and
R. (Ichthyascaris) etelidis Moravec & Justine, 2012
from Etelis coruscans Valenciennes and Pristipo-
moides filamentosus (Valenciennes) (both Lutjanidae)
F. Moravec (&)
Institute of Parasitology, Biology Centre of the Czech
Academy of Sciences, Branisovska 31,
370 05 Ceske Budejovice, Czech Republic
e-mail: [email protected]
J.-L. Justine
Institut Systematique, Evolution, Biodiversite, ISYEB,
UMR7205 CNRS, EPHE, MNHN, UPMC, Museum
National d’Histoire Naturelle, Sorbonne Universites,
CP51, 57 rue Cuvier, 75231 Paris cedex 05, France
123
Syst Parasitol (2015) 92:181–195
DOI 10.1007/s11230-015-9597-5
(Moravec & Justine, 2005, 2006, 2012). Anisakid
nematodes unidentified to species or genera, mostly as
larval stages, have also been reported from fishes
belonging to different families by Justine et al. (2010a,
b, 2012) and Shamsi et al. (2015).
Recent examinations of anisakid nematodes col-
lected from two species of perciform fishes, the
blacksaddled coralgrouper Plectropomus laevis
(Lacepede) (Serranidae) and the blackfin barracuda
Sphyraena qenieKlunzinger (Sphyraenidae), revealed
that they represent two new species of Hysterothy-
lacium Ward & Magath, 1917 plus one species of
larval Contracaecum Railliet & Henry, 1912, which
are described herein.
The blacksaddled coralgrouper P. laevis (maximum
body length 125 cm, weight 24.2 kg) and the blackfin
barracuda S. qenie (maximum body length 200 cm,
weight up to 50 kg) are both tropical marine, reef-
associated fishes. The former has an Indo-Pacific
distribution, whereas the latter is distributed in the
Indo-Pacific from the Red Sea and East Africa to the
central Indian Ocean, French Polynesia and the eastern
Pacific (Mexico, Panama). Both species are targeted
by commercial and recreational fishermen (Froese &
Pauly, 2015).
Materials and methods
Fish were caught off New Caledonia by various
means. The nematodes intended for morphological
studies were fixed in hot 70 % ethanol. For light
microscopical examination (LM), the specimens were
cleared with glycerine. Drawings were made with the
aid of a Zeiss drawing attachment. Specimens used for
scanning electron microscopical examination (SEM)
were postfixed in 1 % osmium tetroxide (in phosphate
buffer), dehydrated through a graded acetone series,
critical-point-dried and sputter-coated with gold; they
were examined using a JEOL JSM-7401F scanning
electron microscope at an accelerating voltage of 4 kV
(GB low mode). All measurements are in micrometres
unless otherwise indicated. The classification system
of the Ascaridoidea adopted follows Keys to the
Nematode Parasites of Vertebrates (Anderson et al.,
2009; Gibbons, 2010). The fish nomenclature follows
FishBase (Froese & Pauly, 2015).
Family Anisakidae Railliet & Henry, 1912
Hysterothylacium alatum n. sp.
Type-host: Blacksaddled colargrouper Plectropomus
laevis (Lacepede) (Perciformes: Serranidae); fork
length 550 mm.
Site in host: Digestive tract (pyloric caecum).
Type-locality: Off New Caledonia, Passe de Teramba
off La Foa (collected 27.iii.2003).
Prevalence and intensity: 1 of 6 fish infected; 6
nematode specimens.
Type-material: Holotype and allotype (anterior and
posterior body ends mounted on SEM stub and
remaining parts of bodies preserved in 70 % ethanol)
plus 2 paratypes in the Helminthological Collection of
the Institute of Parasitology, Biology Centre of the
Czech Academy of Sciences, Ceske Budejovice (Cat.
No. N–1090); 2 paratypes in the Museum National
d’Histoire Naturelle, Paris (MNHN JNC357A).
Etymology: The specific name alatum (=winged) is a
Latin adjective relating to a characteristic feature of
this nematode, i.e. the presence of conspicuously
broad cervical alae.
Description (Figs. 1–3)
General. Body large, elongate, yellowish in colour.
Anterior part of body slender. Broad asymmetrical
cervical alae, widest in region of c. 1/3 of oesophageal
length, extend posteriorly to about level of middle of
oesophagus (Figs. 1D, 2A); from there they continue
posteriorly to tail as narrow cuticular ridges (Figs. 2E,
F, 3A). Deirids not observed. Anterior end with 3 large
lips provided with broad lateral flanges; each lip has
narrow base. Posterior part of dorsal lip roughly
rectangular, broad, with margins of lateral flanges
almost parallel, bears 2 lateral double papillae;
anterior part of dorsal lip much narrower, anteriorly
rounded, separated from posterior part of lip by 2
fairly deep lateral depressions (Figs. 1B, 2B–D).
Subventral lips with 1 double, 1 single papilla and
amphid. Interlabia well developed, conical, reaching
anteriorly to about level of labial papillae (Figs. 1C,
2B–D). Oesophagus cylindrical, long, ending in small
spherical ventriculus; ventricular appendix narrow,
182 Syst Parasitol (2015) 92:181–195
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Fig. 1 Hysterothylacium alatum n. sp. ex Plectropomus laevis. A, Anterior end of young female, lateral view; B, Dorsal lip; C,
Cephalic end of gravid female, sublateral view; D, Anterior body end of largest female, ventral view; E, Tail of largest female, lateral
view; F, Tail tip of largest female, ventral view; G, Tail of male, ventral view; H, Egg; I, Vulva, lateral view; J, Posterior end of male,
ventral view; K, Tail of male, lateral view; L, Posterior end of male, lateral view
Syst Parasitol (2015) 92:181–195 183
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very long. Anterior intestinal caecum short, slightly
longer than length of ventriculus (Fig. 1A, D). Cae-
cum to ventricular appendix length ratio 1:8–18.
Nerve-ring encircles oesophagus at about 1/6 of its
length. Excretory pore at level of nerve-ring or just
posterior to it (Fig. 1A, D). Tail conical; its tip with
numerous minute but distinct protuberances.
Male [Based on 1 specimen, holotype.] Length of
body 42.05 mm, maximum width 558. Lips 105 long;
length of interlabia 45. Length of oesophagus
1.90 mm, representing 4.5 % of body length;
maximum width 190. Nerve-ring and excretory pore
653 and 680, respectively, from anterior extremity.
Ventriculus 109 9 136; ventricular appendix
5.30 mm long, maximum width 204. Intestinal cae-
cum 299 long, with maximum width 82. Caecum to
ventricular appendix length ratio 1:18. Posterior end of
body curved ventrally. Spicules equal, alate, 925 mm
long, representing 2.2 % of body length (Fig. 1L).
Total of 25 pairs of genital papillae present, 17 being
pre-anals, 1 adanal, and 7 postanals; papillae of several
posteriormost pre-anal pairs, adanal pair and of
postanal pairs very small; no double papillae present
Fig. 2 Hysterothylacium alatum n. sp., SEM micrographs. A, Anterior end of female, ventral view; B–D, Cephalic end, apical, dorsal
and subdorsal views, respectively; E, F, Posterior end of male, lateral and ventral views, respectively. Abbreviations: a, double cephalic
papilla; b, single cephalic papilla; c, amphid; d, dorsal lip; i, interlabium
184 Syst Parasitol (2015) 92:181–195
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(Figs. 1G, J–L, 2E, F, 3A). One papilla-like ventro-
median organ located on anterior cloacal lip present
(Figs. 1G,J, L, 2E, F, 3A). Tail conical, 136 long; tail
tip bearing numerous minute protuberances (Figs. 1G,
J–L, 2E, F, 3A, B).
Gravid female [Based on 2 complete and 1 incomplete
ovigerous specimens; measurements of allotype in
parentheses.] Length of body 51.18–87.38 (87.38) mm,
maximum width 598–789 (789). Length of asymmet-
rical cervical alae in allotype (3.67/2.72) mm, maxi-
mum width (299). Lips 136–190 (190) long; length of
interlabia 68–99 (99). Length of oesophagus 3.33–5.30
(5.30) mm, representing 6.0–6.5 (6.0) % of body
length; maximum width 204 (204). Nerve-ring and
excretory pore 612–843 (843) mm and 680–925,
respectively, from anterior extremity. Ventriculus
109–136 9 122–136 (136 9 122); ventricular
appendix 4.64–5.85 (4.64) mm long, maximum width
136 (136). Intestinal caecum 320–571 (571) long,
maximum width 82–95 (95). Caecum to ventricular
appendix length ratio 1:8–18 (1:8). Vulva pre-equato-
rial, 26.38–46.44 (46.44) mm from anterior end of
body, at 52–53 % (53 %) of body length; posterior
vulval lip protrudes distinctly (Fig. 1I). Vagina long (in
allotype 3.40 mm long, 163 wide), directed posteriorly
from vulva. Uterus forms numerous coils, contains
numerous almost spherical eggs 48–51 in diameter in
allotype (Fig. 1H); only immature eggs present in
paratype. Tail conical, 231–680 long (Fig. 1E); tip
rounded, bears numerous small cuticular protuberances
(Fig. 1E, F).
Non-gravid female [Based on 2 specimens.] Length of
body 11.48–14.21 mm, maximum width 258–299.
Maximum width of cervical alae 27–41. Lips 75–78
long; length of interlabia 33–36. Length of oesophagus
1.71–1.90 mm, representing 13.4–14.9 % of body
length; maximum width 82–109. Nerve-ring and
excretory pore 354–367 and 405–408, respectively,
from anterior extremity. Ventriculus 68–109 9 82–95;
ventricular appendix 1.67–1.85 mm long, maximum
width 41. Intestinal caecum 190–204 long, maximum
width 54–68. Caecum to ventricular appendix length
ratio 1:9. Vulva in larger specimen pre-equatorial,
5.98 mm from anterior end of body, at 42 % of body
length; vulval lips not protruding. Uterus empty. Tail
204–218 long; tip rounded, bears numerous small
cuticular protuberances.
Remarks
According to Moravec et al. (2012), a total of 67 valid
species of Hysterothylacium have been reported from
marine, estuarine and freshwater fishes. However, an
additional three species have since been described:
H. gibsoni Xu, Li & Zhang, 2014, H. simile Li, Zhang
& Liu, 2013 and H. zhoushanense Li, Liu & Zhang,
2012 (emend.) (see Li et al., 2012, 2013; Xu et al.,
2014). Consequently, at present this genus contains 70
recognised species.
Of these, as in the new species, the following ten
species possess a markedly short caecum and a long
ventricular appendix, spicules of about 1 mm in length
and the tail tip bearing numerous small cuticular
protuberances or spines: H. amoyense (Hsu, 1933),
H. anguillae Moravec, Taraschewski, Appelhoff &
Fig. 3 Hysterothylacium alatum n. sp., SEM micrographs. A,
Tail of male, ventrolateral view; B, Tail tip of male, lateral view
Syst Parasitol (2015) 92:181–195 185
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Weyl, 2012, H. arnoglossi Petter & Maillard, 1987,
H. fabri (Rudolphi, 1819), H. pelagicum Deardorff &
Overstreet, 1982, H. reliquens (Norris & Overstreet,
1975), H. rhacodes Deardorff & Overstreet, 1978,
H. scomberoideiBruce&Cannon, 1989,H. scombero-
mori Bruce, 1990 and H. zhoushanense (see Norris &
Overstreet, 1975; Deardorff & Overstreet, 1978, 1981,
1982; Petter & Maillard, 1987; Bruce & Cannon,
1989; Bruce, 1990; Li et al., 2008, 2012, 2013;
Moravec et al., 2012; Xu et al., 2014).
Of these ten species, only H. scomberoidei, a
parasite of Scomberoides commersonianus Lacepede
(Carangidae) off Australia, possesses lateral alae
conspicuously expanded in the cervical region, as in
the new species. In all of the other nine species, the
lateral alae are absent (H. amoyense), strongly reduced
(H. anguillae, H. reliquens, H. fabri) or very narrow
(H. arnoglossi, H. pelagicum, H. rhacodes,
H. scomberomori, H. zhoushanense). Hysterothy-
lacium scomberoidei differs from the new species
mainly in the shape of the dorsal lip (lateral flanges of
the posterior part of lip with straight rims vs rims
rounded), a conspicuously shorter ventricular appen-
dix (1.79–2.16 mm in males, 1.74–2.71 mm in
females vs 5.30 mm in male, 4.64–5.85 mm in
females), a non-elevated vulva (vs vulval lips
markedly elevated), a shorter body in gravid females
(23.5–52.5 mm long vs 51.2–87.4 mm) and by larger
eggs (53–60 lm vs 48–51 lm in diameter) (see Bruce
& Cannon, 1989).
Conspicuously broad lateral alae in the cervical
region are also present in H. fortalezae (Klein, 1973),
H. nipponense Moravec & Nagasawa, 1998 (syn.
H. japonicum Moravec & Nagasawa, 1998) and
H. tetrapteri (Bruce & Cannon, 1989) (Klein, 1973;
Deardorff &Overstreet, 1981; Bruce &Cannon, 1989;
Moravec & Nagasawa, 1998a, b; Xu et al., 2014).
However, H. nipponense and H. tetrapteri differ
markedly from the new species in having a very long
caecum, whereas the caecum of H. fortalezae is short,
resembling thus that of H. alatum n. sp. Hysterothy-
lacium fortalezae is a parasite of Scomberomorus spp.
(Scombridae) and allegedly also a carangid and a
serranid in the West Atlantic region (off Brazil and the
USA) (Klein, 1973; Deardorff & Overstreet, 1981).
However, in contrast to the new species, the body size
of H. fortalezae is much smaller (males
12.0–23.4 mm, females 10.0–15.4 mm long vs male
42.1 mm, females 51.2–87.4 mm), the spicules are
shorter (560–680 lm vs 925 lm), the medioventral
precloacal organ is absent (vs present), the ventricular
appendix is much shorter (506–835 lm long in males,
556–661 lm in females vs 5,300 lm in male,
4,638–5,848 lm in females), the length ratio of the
caeca and ventricular appendix is different (1:5.0–6.5
in males, 1:3.4–5.4 in females vs 1:18 in male, 1:8–18
in females), the vulval lips are not protruding (vs
protruding) and the female tail tip bears rather large
cuticular spines (vs numerous small protuberances)
(see Deardorff & Overstreet, 1981). Both species also
differ in the type-host family (Scombridae vs Ser-
ranidae) and geographical regions (Atlantic vs
Pacific).
Fairly broad lateral alae are typical also of
H. aduncum (Rudolphi, 1802), H. auctum (Rudolphi,
1802),H. sinense Li, An& Zhang, 2007 andH. spirale
Rossin, Datri, Incorvaia & Timi, 2011, but all of these
species have a relatively long caecum (Hartwich,
1975; Moravec et al., 1985; Moravec & Nagasawa,
2000; Rossin et al., 2011; Li et al., 2007, 2013).
Hysterothylacium alatum n. sp. has previously been
reported from P. laevis off New Caledonia as
Hysterothylacium sp. by Justine et al. (2010a). Figus
et al. (2005) recorded adultHysterothylacium sp. from
the serranid fish Serranus cabrilla (Linnaeus) in the
southwestern Mediterranean, which, as visible from
photos provided, seems to be morphologically similar
to H. alatum n. sp. However, judging from the
different host genera and remote geographical regions,
both these forms probably belong to different species.
From off New Caledonia, two other nematode
species were recently described from a congeneric
host, Plectropomus leopardus (Lacepede), namely the
trichosomoidid Huffmanela plectropomi Justine, 2011
and the capillariid Capillaria plectropomiMoravec &
Justine, 2014 (Justine, 2011; Moravec & Justine,
2014). It is likely that these two species can also
parasitise both Plectropomus leopardus and P. laevis
in the shared environment, as suggested by the finding
of unidentified capillariids in both species by Justine
et al. (2010a).
Hysterothylacium sphyraenae n. sp.
Type-host: Blackfin barracuda Sphyraena qenie Klun-
zinger (Perciformes: Sphyraenidae); fork length
630 mm, weight 1.5 kg
186 Syst Parasitol (2015) 92:181–195
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Site in host: Stomach.
Type-locality: Fish caught by trolling, off Noumea,
New Caledonia (collected 14.iv.2003).
Prevalence and intensity: Single fish examined; 3
nematode specimens.
Type-material: Holotype and allotype in the Museum
National d’Histoire Naturelle, Paris (MNHN
JNC394E).
Etymology: The specific name of this nematode relates
to the genitive form of the generic name of the host.
Description (Figs. 4–6)
General. Medium-sized nematodes with transversely
striated cuticle (Figs. 5A–G, 6B), green when alive,
whitish in ethanol. Maximum width near middle of
body. Lips almost equal in size (dorsal lip slightly
smaller than ventrolateral lips), slightly shorter than
wide, with narrow bases; their lateral flanges widest
just posterior to middle of lips; pulp with 2 anteriorly
protruding lobes. Dorsal lip with 2 subdorsal double
papillae; each subventral lip with 1 double subventral
papilla, 1 small single papilla and amphid situated
laterally (Figs. 4B, C, 5A, B, D). Interlabia well
developed, low, about 1/3 length of lips (Figs. 4C, 5A,
B, D). Cervical alae very narrow, starting about level
of lip bases, extending posteriorly in both sexes as
cordons almost to end of tail (Figs. 4E, 5C, E–G).
Deirids just posterior to level of nerve-ring (Fig. 4B).
Oesophagus long, slightly broader posteriorly than
anteriorly. Nerve-ring encircles oesophagus at about
one sixth of its length. Ventriculus small, almost
spherical; ventricular appendix long, narrow. Intesti-
nal caecum markedly short. Excretory pore just
posterior to nerve-ring (Fig. 4A). Tail of both sexes
conical; tip lacks distinct cuticular outgrowths visible
under LM.
Male [Based on 2 specimens; holotype; measurements
of paratype in parentheses.] Length of body 18.39
(18.71), maximum width 558 (544). Deirids slightly
asymmetrical, 544/589 (544/571) from anterior
extremity. Width of cervical alae 27(27). Lips 96
(93) long; length of interlabia 39 (45). Length of
oesophagus 2.51 (2.46) mm, representing 13.7
(13.2) % of body length; maximum width 122 (109).
Nerve-ring 517 (503) from anterior extremity; excre-
tory pore just posterior to nerve-ring. Ventriculus
95 9 105 (136 9 150); ventricular appendix 1.41
(1.52) mm long, maximum width 136 (109). Intestinal
caecum 204 (150) long, with maximum width 109
(109). Caecum to ventricular appendix length ratio 1:7
(1:10). Posterior end of body curved ventrally.
Spicules equal, alate, 762 (830) long, representing
4.1 (4.4) % of body length; fairly broad ventral
spicular ala forms distinct spike somewhat anterior
to mid-length of spicule (Fig. 4G). Total of 38 (37)
pairs of small subventral papillae present, 28 (27)
being pre-anals and 10 (10) postanals; papillae of
several posteriormost pre-anal and postanal pairs very
small; papillae of 4th subventral postanal pair doubled.
One papilla-like ventromedian organ located on
anterior cloacal lip present (Figs. 4D, E, G, 5C, E–
G, 6B). Posterior cloacal lip with granular surface
(Figs. 4E, 5F, G). Tail conical, 150 (150) long,
markedly narrowed at its distal third; tip obtusely
pointed, without caudal projections visible under LM,
but with few poorly developed protuberances visible
under SEM (Figs. 4D, E, G, 5C, E–G, 6A).
Female [Based on 1 specimen containing immature
eggs, allotype.] Length of body 19.11 mm, maximum
width 571. Lips 93 long. Length of interlabia 39.
Length of oesophagus 2.56 mm, representing 13.4 %
of body length; maximum width 272. Nerve-ring and
excretory pore 490 and 558, respectively, from
anterior extremity. Ventriculus 109 9 109; ventricu-
lar appendix 1.32 mm long, maximum width 95.
Intestinal caecum 245 long, maximum width 68.
Caecum to ventricular appendix length ratio 1:5.
Vulva pre-equatorial, 7.11 mm from anterior end of
body, at 37 % of body length. Vagina about 1.63 mm
long, directed posteriorly from vulva. Uterus forms
numerous coils and contains only immature eggs. Tail
conical, 340 long; tip obtusely pointed, without any
caudal projections visible under LM (Fig. 4F).
Remarks
Of the 70 previously described, recognised species of
Hysterothylacium (see above), 19 are characterised by
the presence of a markedly short intestinal caecum and
a long ventricular appendix; these features also typical
of H. alatum n. sp. and H. sphyraenae n. sp. However,
in contrast to H. sphyraenae n. sp., some of these
species possess conspicuously broad cervical alae
(H. alatum,H. fortalezae andH. scomberoidei) or their
spicules are much shorter, i.e. not exceeding 0.5 mm
Syst Parasitol (2015) 92:181–195 187
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Fig. 4 Hysterothylacium sphyraenae n. sp. ex Sphyraena genie. A, Anterior body end of female, lateral view; B, Cephalic end of male,
dorsal view; C, Same, enlarged; D, Posterior end of male, ventral view; E, Tail of male, ventral view; F, Tail of female, lateral view; G,
Posterior end of male, lateral view
188 Syst Parasitol (2015) 92:181–195
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Fig. 5 Hysterothylacium sphyraenae n. sp., SEM micrographs. A, Dorsal lip, dorsal view; B, Ventrolateral lip, ventrolateral view; C;
Posterior end of male, lateral view; D, Cephalic end, lateral view; E, Posterior end of male, ventral view; F, G, Tail of male, ventrolateral
and lateral views, respectively (arrow indicates postanal double papilla). Abbreviations: a, double cephalic papilla; b, single cephalic
papilla; c, amphid; e, precloacal median organ; g, cloacal aperture; i, interlabium
Syst Parasitol (2015) 92:181–195 189
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(H. gibsoni, H. physiculi Moravec & Nagasawa, 2000
and H. winteri Torres & Soto, 2004) or much longer,
i.e. not less than 1.3 mm [H. bifidalatum Petter &
Maillard, 1987, H. chaunaxi (Olsen, 1952), H. pelag-
icum and H. reliquens] (see e.g. Deardorff & Over-
street, 1981; Petter & Maillard, 1987; Bruce &
Cannon, 1989; Moravec & Nagasawa, 2000; Torres
& Soto, 2004; Xu et al., 2014).
Although most of the remaining 11 species have
narrow lateral alae, resembling H. sphyraenae, almost
all of these species are characterised by the presence of
numerous, distinct cuticular spines or protuberances
on the tail tip, which are readily visible under the LM
(H. amoyense, H. anguillae, H. arnoglossi, H. fabri,
H. rhacodes,H. scomberomori andH. zhoushanensis).
In contrast, three species, H. cornutum (Stossich,
1904), H. dollfusi (Schmidt, Leiby & Kritsky, 1974)
and H. ogcocephali (Olsen, 1952), were described as
lacking such ornamentation on the tip of the tail (e.g.
Schmidt et al., 1974; Deardorff & Overstreet, 1981;
Bruce & Cannon, 1989; Moravec & Nagasawa, 2000).
However, it is worth noting that two of them,
H. dollfusi and H. ogcocephali, were studied only
under the LM and the tail tip of H. cornutum was
observed by SEM only under low magnification
(Bruce & Cannon, 1989). The tail tip of all specimens
of H. sphyraenae studied under the LM appeared to
lack any cuticular ornamentation, resembling that in
H. cornutum, H. dollfusi and H. ogcocephali; only at a
very high magnification did the tail tip reveal the
presence of a few minute protuberances (Fig. 6A).
Hysterothylacium sphyraenae differs from H. cor-
nutum, a parasite of Thunnus spp., mainly in the absence
of ventral, precloacal, cuticular ornamentation, the
presence of a pair of double postanal papillae, the shape
of the female tail (markedly elongate inH. cornutum) and
its somewhat shorter spicules (Deardorff & Overstreet,
1982; Bruce & Cannon, 1989; Moravec & Nagasawa,
2000). It differs mainly from H. dollfusi, a specific
parasite of the freshwater paddlefish Polyodon spathula
(Walbaum) in North America, by the presence of lateral
alae, more numerous pairs of pre-anal papillae (27–28 vs
19–20) and somewhat shorter spicules (0.76–0.83 mm vs
1.07–1.45 mm) (Schmidt et al., 1974). From H. ogco-
cephali, a specific parasite of Ogcocephalus radiatus
(Mitchill) in theNorthAtlantic region, by the shape of the
lips (conspicuously elongate in H. ogcocephali), more
numerous pairs of postanal papillae (10 vs 3–4) and
somewhat longer spicules (762–830 vs 330–660 lm)
(Deardorff & Overstreet, 1981). A characteristic feature
of the new species, not reported in other Hysterothy-
lacium spp., is the presence of a distinct ventral spike
formed by each spicular ala (Fig. 4G).
Hysterothylacium sphyraenae is the first valid
nominal species of this genus described from fishes
of the family Sphyraenidae. Williams & Williams
(1996) listed ‘‘H.marinum’’ from Sphyraena barracu-
da (Walbaum) in the Pacific Ocean, but this informa-
tion is based on evident species misidentification. The
taxonomic status of the anisakid originally established
as Gordius marinus Linnaeus, 1767 remains uncertain
and the records of Contracaecum orHysterothylacium
marinum reported by Yamaguti (1935), Deardorff &
Overstreet (1981) and Moravec & Nagasawa (2000)
relate, in fact, to H. rigidum (Rudolphi, 1809). In
contrast to H. sphyraenae, H. rigidum is a specific
Fig. 6 Hysterothylacium sphyraenae n. sp., SEMmicrographs.
A, Tail tip of male, lateral view; B; Postanal double and single
papillae
190 Syst Parasitol (2015) 92:181–195
123
parasite of the Lophiidae in Europe, reported also off
Japan, and it is characterised by a very long caecum
extending anteriorly nearly to the level of the nerve-
ring, spicules usually longer than 1 mm and by the
presence of distinct numerous cuticular spines at the
tail tip in both sexes (Yamaguti, 1935; Hartwich,
1975; Deardorff & Overstreet, 1981; Moravec &
Nagasawa, 2000).
Unidentifiable ascaridoid larvae were inadequately
described as Ascaris sphyranurae Linstow, 1907 from
the body cavity of Sphyraena barracuda (reported as
Sphyranura barracuda) off Tasmania, Australia by
Linstow (1907a); apparently, S. barracuda only served
as a paratenic host. Adults or larvae of Hysterothy-
lacium, not identified to species, have frequently been
reported from other species of congeneric hosts
throughout the world (e.g. Petter & Sey, 1997;
Williams & Williams, 1996; Al-Zubaidy et al., 2012).
Contracaecum sp. third-stage larvae
Host: Blacksaddled colargrouper Plectropomus laevis
(Lacepede) (Perciformes: Serranidae); fork length
860 mm, weight 13.2 kg.
Site in host: Ensheated around intestine; bodies of
some specimens ensheathed by thin-walled capsule.
Locality: Off Noumea, New Caledonia, Recif Abore
(collected 2 July 2006).
Prevalence and intensity: 1 of 6 fish examined; 5
nematode specimens.
Voucher specimens: Museum National d’Histoire
Naturelle, Paris (MNHN JNC1887).
Description (Figs. 7, 8)
[Based on 5 specimens.] Body robust, whitish,
45.71–66.10 mm long and 1.22–1.59 mm wide. Cuticle
finely transversely striated (Fig. 8A–D), lateral alae
absent. Cephalic end rounded, with anteriormost part
somewhat elevated, separated from rest of body by
groove (Figs. 7B, C, 8A–C). Oral aperture demarcated
by2broad, lobular elevations (anlagenof lips) protruding
out of mouth, 12–41 high, 1 dorsal and 1 U-shaped
ventral; latter bearing small ventral cuticular tooth
(Figs. 7B, C, 8A–C). Four submedian cephalic papillae
surround oral aperture (Figs. 7B, C, 8A–C). Excretory
pore situated immediately posterior to ventral cephalic
tooth (Figs. 7B, E, 8A–C). Oesophagus narrow,
1.80–2.19 mm long, 163–204 wide. Ventriculus small,
rounded, size 136–204 9 122–190; posterior ventricular
appendix conspicuously large, 5.17–5.83 mm long,
326–490 wide. Nerve-ring 313–488 from anterior
extremity. Intestinal caecum short, extends only short
distance anterior to ventriculus; length 408–558, maxi-
mum width 204–218 (Fig. 7A). Length ratio of caecum
and ventricular appendix 1:10–14. Genital primordium
indistinct. Tail conical, 190–218 long, with few minute
terminal cuticular spines not visible in all specimens
(Figs. 7D, 8D).
Fig. 7 Contracaecum sp. third-stage larva ex Plectropomus
laevis. A, Anterior end of body, lateral view; B, Cephalic end,
apical view; C, Cephalic end, lateral view; D, Tail, lateral view;
E, Cephalic end, lateral view
Syst Parasitol (2015) 92:181–195 191
123
Remarks
The general morphology of these larvae, especially the
structure of the digestive tract and the location of the
excretory pore, indicates that they belong to Contra-
caecum. Species of this genus are parasites of fish-
eating birds and marine (rarely freshwater) mammals,
except sirenians (Anderson et al., 2009). However, as
compared with the known third-stage larvae of other
congeneric species, these larvae are considerably
larger (up to c.60 mm vs at most about 26 mm in
other congeners) (e.g. Anderson, 2000; Moravec et al.,
1993;Moravec &Van As, 2015) and their tail tip bears
a few minute cuticular spines, not reported for larvae
of other Contracaecum spp.
On the other hand, they are rather similar to adults
of the genus Paraheterotyphlum Johnston & Mawson,
1948, parasites of sea snakes in the Pacific region
(Johnston & Mawson, 1948; Schmidt & Kuntz, 1973;
Sprent, 1978), particularly in having a very long
ventricular appendix and a short caecum, the presence
of minute cuticular spines on the tail tip (found in
Paraheterotyphlum fourth-stage larvae; Sprent, 1978)
and in the large body measurements. However, adults
of Paraheterotyphlum spp. are 61–158 mm long
(Sprent, 1978), whereas those of Contracaecum spp.
are at most 90 mm long in C. osculatum (Rudolphi,
1802) (see e.g. Baylis, 1937; Mozgovoy, 1953;
Hartwich, 1975). However, according to Sprent
(1978), the excretory pore of P. australe Johnston &
Mawson, 1948 (the type-species of Paraheteroty-
phlum) is located slightly posterior to the nerve-ring,
whereas that in the present larvae is found just
posterior to the cephalic larval tooth (Fig. 8A–C).
Therefore, these larvae appear to belong to Contra-
caecum. In having minute cuticular spines at the tail
tip, they also resemble fourth-stage larvae of some
Hysterothylacium spp., but differ distinctly from them
by the location of the excretory pore, the much less
developed anlagen of lips and the markedly larger
body measurements.
Third-stage larvae of Contracaecum have fre-
quently been reported from the internal organs of
many species of freshwater, brackish-water andmarine
Fig. 8 Contracaecum sp. third-stage larva ex Plectropomus laevis, SEM micrographs. A, Cephalic end, lateral and apical views; B,
Cephalic end, apical view (arrow indicates ventral tooth); C, Cephalic end, apical view (another specimen) (arrow indicates ventral
tooth); D, Tail, ventral view. Abbreviations: a, cephalic papilla; c, cloacal aperture; e, excretory pore; o, oral aperture
192 Syst Parasitol (2015) 92:181–195
123
fishes, which serve as paratenic hosts (Anderson, 2000;
Moravec, 2009, 2013). Unfortunately, the species
identification of Contracaecum larvae from fishes
based on morphometrical features is practically
impossible. Judging by the structure of the digestive
tract, and especially the markedly short caecum and
long ventricular appendix, the present larvae tend to
resemble the adults ofC. rectangulum (Linstow, 1907),
as illustrated by Linstow (1907b) (see also Mozgovoy,
1953). This parasite of Antarctic seals was later
considered a junior synonym of C. osculatum (Rudol-
phi, 1802) by Baylis (1937), although Mozgovoy
(1953) did not agreewith this synonymy (the caecum is
much longer than the ventricular appendix in C. oscu-
latum). However, according to Linstow (1907b), the
body lengths of C. rectangulum is only 40 mm and
55–60 mm, respectively, for the male and females,
which is not comparable with the present third-stage
larvae. Apparently, these larvae belong to another,
perhaps undescribed species of Contracaecum.
Acknowledgements We thank Claude Chauvet (UNC,
Noumea) for providing fish, and Ronald Fricke (Staatliches
Museum fur Naturkunde, Stuttgart, Germany) for identifying the
barracuda (from photographs). Thanks are also due to the staff of
the Laboratory of Electron Microscopy, Institute of Parasitology,
BCCAS, in Ceske Budejovice for their technical assistance, and to
Blanka Skorıkova of the same Institute for help with the
illustrations. The authors also thank two anonymous reviewers
for their helpful suggestions, and to David Gibson, Natural History
Museum, London, for the linguistic revision of the MS.
Funding This study was partly supported by the Institute of
Parasitology (with institutional support RVO 60077344) and the
Czech Science Foundation (Project No. P505/12/G112).
Compliance with ethical standards
Conflict of interest The authors declare that they have no
conflict of interest.
Ethical approval All applicable institutional, national and
international guidelines for the care and use of animals were
followed.
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