E. Řehulková1, J.-L. Justine2, M. Gelnar1
1Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37
Brno, Czech Republic
2Équipe Biogéographie Marine Tropicale, Unité Systématique, Adaptation, Évolution (CNRS, UPMC,
MNHN, IRD),
Institut de Recherche pour le Développement, BP A5, 98848 Nouméa Cedex, Nouvelle Calédonie
DACTYLOGYRIDS (MONOGENEA, PLATYHELMINTHES)
FROM THE ESOPHAGUS OF THE DEEP-SEE FISH HOPLICHTHYS CITRINUS (SCORPAENIFORMES: HOPLICHTHYIDAE)
Host: Hoplichthys citrinus (5 deeply frozen specimens).
Locality: Seamount Nova (22°48'S, 159°22'E), depth 330 m, south of the Chesterfield Islands, New
Caledonia.
Site: Esophagus.
Specimens examined: 7 flattened specimens fixed with GAP; 13 unflattened specimens fixed in 70 %
ethanol and stained with Schneider’s carmine.
Pharynx and esophagus of marine fishes
Endoparasitic dactylogyrids from the fish digestive system
Diplectanotrema Johnston & Tiegs, 1922
Pseudempleurosoma Yamaguti, 1965
Paradiplectanotrema Gerasev, Gayevskaya & Kovaleva, 1987
Pseudodiplectanotrema Gerasev, Gayevskaya & Kovaleva, 1987
Metadiplectanotrema Gerasev, Gayevskaya & Kovaleva, 1987
Neodiplectanotrema Gerasev, Gayevskaya & Kovaleva, 1987
Enterogyrus Paperna, 1963
Stomach of freshwater fishes
INTRODUCTION: The large majority of monogeneans are branchial or cutaneous ectoparasites and
relatively few of them are known to parasitise internal organs. Among those of the Dactylogyridae,
seven genera (see below) have been proposed to accommodate species colleted from the digestive
systems of freshwater and marine fishes.
Enterogyrus sp.
Hoplichthys citrinus Gilbert, 1905
RESULTS: During recent surveys of helminth parasites of marine fishes off New Caledonia, South
Pacific, 20 specimens of conspecific monogeneans were recovered from the esophagus of the deep-sea
fish Hoplichthys citrinus (Hoplichthyidae) collected in the region of the Chesterfield Islands
(Coral Sea, about halfway between New Caledonia and Australia). The specimens found were
preliminary assigned to Paradiplectanotrema lepidopi based on the morphology of the sclerotised
structures (see on the right). However, re-examination of the type specimens of Diplectanotrema
balistes, Pseudempleurosoma carangis, and vouchers of Paradiplectanotrema lepidopi showed that the
type species of these genera share many more common features than it was believed earlier, and
therefore it is likely that all these genera are synonyms.
Distribution, ecology, habitat:
Benthic on soft-bottom habitats of the outer continental shelves and upper continental slopes (c.
100-435m) of the tropical west-central Pacific.
Paradiplectanotrema lepidopi
Gerasev, Gayevskaya & Kovaleva, 1987
from Hoplichthys citrinus
A: id – intestinal diverticulum; vf – vitelline follicles. B: t – testis; vd – vas deferens; sv –
seminal vesicle; pr – prostatic reservoir
o – ovary; mg – Mehlisglands; e – egg; u – uterus; ma – muscular aperture;
gp -genital porus
Paradiplectanotrema lepidopi from Lepidopus caudatus (Perciformes: Trichiuridae); North Atlantic
Ocean: vouchers (USNPC 094763.00). Sclerotised structures: da – dorsal anchors; db – dorsal bar; va
– ventral anchors; vb – ventral bar(s); h – hook; co – copulatory organ
da
da
va
db
vb
h
va
co
da
da
va
db
vb
h
va
co
da
Paradiplectanotrema lepidopi from Hoplichthys citrinus; southwest Pacific. Sclerotised structures:
da – dorsal anchors; db – dorsal bar; va – ventral anchors; vb – ventral bar(s); h – hook; co –
copulatory organ
Paradiplectanotrema lepidopi from Hoplichthys citrinus (Nomarski DIC). : A. Haptor; B. Copulatory
organ
A
B
vf
id
A
vd
t
u
sv
o
e
ma
gp
mg
pr
B
CONCLUSIONS and FURTHER WORK:
•Species of Diplectanotrema, Pseudempleurosoma and Paradiplectanotrema share the same composition
of the haptoral hard structures and general features of internal anatomy, which signifies the close
relationship between the 3 genera and raises the question of synonymy.
•Our examination revealed some errors in the original diagnosis of the above genera but a „mass“
concerning the presence and position of the vagina remains unidentified.
•Live specimens and histological sections of a newly collected specimens of the
diplectanotrema-like dactylogyrids can provide helpful insights into the position of the vagina and
the structure of the intestine.
Our examination of the type materials of Pseudempleurosoma carangis showed that the structure
originally noted as the ventral bar attached to the ventral anchor is in reality markedly elongated
outer root. Therefore, we believe that the haptor has only 2 instead 4 ventral bars.
In the original description of Diplectanotrema balistes, Johnston and Tiegs (1922) stated that the
haptor possesses only 1 pair of simple bars. Nevertheless, our examination of its type specimens
revealed that the haptor actually contains 1 dorsal and 2 ventral bars. Also the accessory piece of
the copulatory organ is absent in the original drawings.
Diplectanotrema balistes (MacCallum, 1915): syntype (USNPC 035696.02) from Balistes capriscus
(Tetraodontiformes: Balistidae)
da
da
va
va
db
vb
co
h
Pseudempleurosoma carangis Yamaguti, 1965: holotype (USNPC 063505.00) from Caranx lugubris
(Perciformes: Carangidae)
da
da
va
va
db
vb
co
h
Acknowledgments:
This study was supported by Ichthyoparasitology Research Centre, Project No. LC 522 and Research
Project of Masaryk University, MSM 0021622416.
Composite whole-mount drawing: specimen from Sarotherodon galilaeus
Composite whole-mount drawing: syntype (USNPC 035696.02) from Balistes capriscus
Thickness of the tegument
Presence of the head organs
Morphology of the haptor
Structure of the intestine
Position of the gonads
Distribution
of the vitelline follicles