A new species of Haliotrema (Monogenea: Ancyrocephalidae) from a Japanese puffer fish Takifugu niphobles (tetraodontiformes: Tetraodontidae)

8

0020-7519/93 166.00 + 0.00 Pergamon Press Lid Societyfir Parasitology

1993 Austrolim

A NEW SPECIES OF HALIOTREMA (MONOGENEA: ANCYROCEPHALIDAE) FROM A JAPANESE PUFFER FISH TAKIFUGU NIPHOBLES (TETRAODONTIFORMES: TETRAODONTIDAE)

G. J. KLASSEN* Division

of Fishes, Natural

History

Museum,

Smithsonian

Institution,

Washington,

DC 20560,U.S.A.

(Received 19 October 1992; accepted 3 March 1993) Abstract-KLAssaN G. J. 1993. A new species of Haliotrema (Monogenea: Ancyrocephalidae) from a Japanese puffer fish Takifugu niphobles (Tetraodontiformes: Tetraodontidae). International Journal for Parasitology 23: 777-783. A new species of Huliotrema is described on the basis of material from the gills of the Japanese puffer fish Tukifugu niphobles. The new species is compared to other ancyrocephalids from tetraodontid hosts and congeners with similar copulum morphology from unrelated hosts. It is distinguished from these species based on a combination of reproductive and haptoral characters. Comparison of the haptor musculature of the new species with that described for Huliofrema balisticus revealed a potential for additional taxonomic characters. Resolution of differences in the interpretation of the functional morphology of the muscle groups in the two species will require further investigation. INDEX

KEY WORDS:

Haliolrerna; Monogenea;

Takijiigu; puffer fish; Tetraodontidae.

PhD dissertation, University of Toronto, 1992). Details of the haptoral musculature are compared to a similar study of H. balisticus conducted by Kearn (1971).

INTRODUCTION

FEW Monogenea have been recorded from tetraodontid hosts (Wheeler & Klassen, 1988; Ogawa, 1991) and of these only 3 species are members of the Ancyrocephalidae. Haliotrema obesum (Caballero, Bravo-Hollis & Grocott, 1955) was recorded from Arothron hispidus off the Pacific coast of Panama (Caballero et al., 1955) and off Queensland (Young, 1968); Ancyrocephalus ornatus Yamaguti, 1968 was recorded from Arothron hispidus off Hawaii (Yamaguti, 1968); Thylacicleidus serendipitus Wheeler and Klassen, 1988 was recorded off the fresh water puffer Tetraodon nigroviridus from Indonesia [Wheeler & Klassen, 1988; these authors erroneously reported the host as T.juviatilis, and the generic designation, sensu Dekkers (1975), may be inaccurate (Tyler, 1980)]. In this paper I present the description of a new species of Haliotrema from the Japanese puffer Takifugu niphobles. This new species is compared to the above-mentioned ancyrocephalids from tetraodontid hosts in addition to other congeners with similar copulum morphology (Klassen, unpublished

*Present

address

of Biology, St Mary’s Canada B3H 3C3.

MATERIALS AND METHODS Dr K. Ogawa (Department of Fisheries, University of Tokyo) sent material of an undescribed species of Haliotrema from a Japanese puffer (Tukifugu niphobles). This material consisted of 68 specimens mounted on 8 slides. Material on 4 slides was collected from fishes reared at the Fisheries Laboratory, University of Tokyo. They were fixed in Schaudinn’s solution; 2 of these slides were stained with Heidenhein’s iron hematoxylin, the other 2 slides with alum carmine. Material on the remaining 4 slides was collected at Hagi, Yamaguchi Prefecture. Two of the slides were fixed in ammonium picrate-glycerin, the other 2 sides were fixed in AFA and stained with alum carmine. All specimens were mounted in Canada balsam. Reconstruction of soft body morphology, sclerite drawings and morphometric measurements were accomplished according to the protocol outlined by Klassen (1991). RESULTS

Haliotrema kusafugu new species Description. Body elongate. Head organs in two fields. Peduncle variously prominent, depending on state of contraction. Indistinct ridges over entire tegument.

c/o Dr

David Cone, Department University, Halifax, Nova Scotia,

777

778

G. J. KLASSEN

FIGS. 2-6. Haliofrema kusajiigu new species, haptoral sclerites. 2: ventral hamulus. 3: ventral transverse bar. 4: doral hamulus. 5: dorsal transverse bar. 6: marginal hook. Scale bar = 50 pm.

FIG. I. Haliotrema kusafugu new species, whole animal, ventral view. Drawing is a composite based on the holotype. Scale bar = SOOpm.

Two pairs of eyes present near anterodorsal and dorsolateral surface of pharynx, posterior pair larger than anterior. Cephalic glands parallel with anterior margin of intestine; glands opening anterolaterally via three bilaterally symmetrical pairs of ducts on lateral margins of head. Mouth midventral in head, opening posterodorsally into pharynx. Oesophagus indistinct. Intestinal caeca passing posteriorly along lateral body margin, uniting just anterior to peduncle (Fig. 1). Haptor truncate, wider than long. Two pairs of hamuli, 1 ventral 1 dorsal, with associated transverse bars, 14 marginal hooks, and kidney-shaped “nephroids” present (“nephroids” is introduced to replace the more cumbersome term “kidney-shaped

structure” used in the past). Superficial roots of ventral hamuli moderately elongate, with hamular loops. Deep root short. Shaft evenly curved. Root/ shaft junction apparent but groove absent (Fig. 2). Ventral transverse bar with straight median portion, pair of lateral projections reduced. Two flanges with keyhole-like foramen arising at junction between median portion and lateral projections of transverse bar for muscle attachment (Fig.3). Dorsal hamuli smaller than ventral. Superficial roots elongate with terminal cap, longer than deep. Deep roots elongate to just beyond level of notch. Shaft evenly curved. Root/ shaft junction apparent but transverse crimp absent (Fig. 4). Dorsal transverse bar slightly smaller than ventral with straight median portion and pair of lateral projections. Flange arising along median surface for muscle attachment (Fig. 5). Marginal hooks large, of equal size, and typical ancyrocephalid distribution. Domus present (Fig. 6). Four distinct groups of muscle/tendon associated with movement of ventral hamuli. Long, thin, paired group of muscles originate in interstitial tissue at about level of testis, passing posteriorly and inserting on lateral surface of nephroid (Fig. 7, ‘ml’). Large group of widespread muscle fibres originate in interstitial tissue of haptor at level of peduncle, collect together in funnel-shaped band of muscle which inserts on distal tip of superficial root (Fig. 7, ‘m2’). Similar muscle group associated with superficial root of dorsal hamuli. Thin band of muscle/tendon inserting on median surface of nephroids, connecting the pair of structures (Fig. 7, ‘m3’). This median band runs parallel with transverse band of muscles at level of peduncle. An additional pair of muscles/tendons arises on posteromedial surface of nephroids, passing

A new species of Haliotrema from a puffer fish

FIG. 7. Haliotrema kusafugu new species, haptor, ventral view. n = nephroid, tb = transverse bar, vh = ventral hamulus, = four muscle groups associated with haptoral sclerites, for details see description in text. Scale bar = 50 pm.

medially to insert on anteriorly oriented flanges of ventral transverse bar (Fig. 7, ‘m4’). Additional muscular connections were observed between lateral projections of both ventral and dorsal transverse bars and deep roots of associated hamuli. Testis posterior to ovary; dorsally overlying posterior margin of ovary (Fig. 8). Vas deferens arising from anterosinistral margin of testis (Fig. 8), short, constricted duct (Fig. 11) entering proximally expanded region (Figs. 8 and 11) which contracts before looping dorsoventrally around left intestinal caecum, passing anteromedially to left of base of copulum (Fig. 8); just anterior to level of base it loops posteriorly to form small, muscular seminal vesicle, duct leading from seminal vesicle to enter copulum base along with ducts from prostatic reservoirs (Figs. 8 and 9). Prostatic ducts receiving secretions from diffuse prostatic glands in region around copulum, ducts leading anteriorly to enter prostatic reservoirs. Two prostatic reservoirs of unequal size present alongside seminal

779

ml4

vesicle, forming posterior loop after receiving prostatic ducts, passing posteriorly just past base of copulum to loop anteriorly and enter base (Figs. 8 and 9). Copulum consisting of shaft and base. Shaft narrows just distal to shaft/base junction, curving slightly anteriorly; opening oblique. Base short, distally inflated; terminal opening directed laterally to body axis; posterior margin slightly enlarged (Fig. 10). Retractor muscle attached to enlarged portion of base. Copulum enclosed by non-muscular sheath extending from base to shaft opening. No accessory piece or spiralling filament present. Ovary ovoid, oviduct arising from anterior margin of ovary, passing anteriorly to open ventrally just posterior to male genital pore. Mehlis glands on anterolateral margin of ovary, ducts leading to oviduct just anterior to ovary (Fig. 8). Vitellaria throughout body from lateral body margin medially around dorsal and ventral margins of intestine. Vitelline collecting ducts arising in midbody region, leading medially to

G. J. KLASSEN

780

TABLE 1-COMPARATIVEMORPHOMETRICMEASUREMENTS(~M)FOR Haliotremakusafugu,

H. kusafugu

H. kurodai Ogawa & Egusa (1978) Range

Present Study

Variable

N

Body length width Haptor length width Pharynx diameter Dorsal hamulus a b

68 68 68 68 65 66 66 66 66 66 66 66 66 66 67 67 67 68 68 68 68 68 68 68 68 68 67 67 67 66 67 68 61 68 68

: e

D bar length 1 2 width Ventral hamulus

a b d

V bar length 1 L

width Marginal hook I Copulum shaft 1 max w min w base length max w

Means f S.D. 1202~t208 307 f 48 102* 18 216f4l 8O~t 14 43*3 33~k2 30&2 14f2 20f2 25*2 l3*2 llf2 35f3 66*6 47&6 7f2 47f3 45&2 38+2 22*2 31*2 29f2 16+2 12*2 53f4 74f6 43*6 llf2 13fl lllf7 8fl 3fl 13f2 26f3

H. kurodai~~D Thylacicleidusserendipitus

Range SOS-1702 175423 60-135 130-322 50-108 3450 26-38 25535 9-19 16-24 19-31 9-18 6-15 25-41 5 l-78 35-61 3-11 38-5 1 3749 3342 15-28 24-37 22-34 I l-20 7-19 44-62 56-93 32-65 615 11-16 90-132 5-11 2-5 S-17 19-31

490-850 130-179 62283 82-123 37-50 25 (23-27)

T. serendipitous Wheeler & Klassen (1988) Mean (Range) 3 19 (232430) 110 (622156) 53 (42-81) 73 (57-105) 25 (19-34) 29 (2640) _

_ _

_ 28 (25-35)

46

(38-56)

3-5 26 (2428)

29

(2042) _ _ _ _ _

46

(30-67) _ _

_ 27 (25-30) 24 9-11 3348* 7-9 I Z-2

17 (1618) 148 (11 l-193** _

* = straight line measurement. ** = combined shaft and base length. N = number of individual measurements per able. enter oviduct via conspicuous expansion at level of opening for Mehlis glands and vitelline collecting ducts (Fig.@. Egg a rounded tetrahedron with single polar filament. Material examined. Sixty-eight specimens. Holotype (note that as the holotype was mounted with several other specimens on the same slide it is distinguished in being encircled in a ring made with a diamond pencil on the undersurface of the slide) and paratypes deposited with MPM (Meguro Parasitological Museum, Tokyo), additional paratypes

deposited Museum,

with USNM (United States National Parasitology Collection, Beltsville, MD). Type host. Tukifugu niphobles, (Tetraodontiformes: Tetraodontidae), Japanese common name: kusa-fugu. Type locality. Hagi, Yamaguchi Prefecture. Etymology. The specific epithet “kusa-fugu” is derived from the Japanese common name for the type host, Takifugu niphobles. This species is named in honor of Dr Kazuo Ogawa, who generously based.

donated

the specimens

on which

this work

is

A new species of Haliotrema from a puffer fish

781

prostatic reservoir with 2 or more prostatic ducts leading into it (Klassen, 1991, dissertation cited above). The proximate expansion of the vas deferens of H. kusufugu was not reported for either T. serendipitus or H. kurodui. However, Yamaguti (1968) did report a similar expansion for H. bodiuni, H. minutospirule, and H spirule.

All 3 species with similar copulum morphology (H. T. serendipitus, and H. kurodui) also lack the crimp and groove of dorsal and ventral hamuli so distinctive for many Huliotremu species (Klassen, 1991, dissertation cited above). However, the crimp is also absent in H. caballeroi, H. trochaderoi, and H. minutum, and presence/absence has not yet been determined for H. epinepheli, H. btfiircocirrus, and H. recurvutum. Similarly, the groove is absent in H. kusufugu,

obesum,

H. epinepheli,

trochuderoi,

FIG. 8. Haliotrema kusafigu new species, male and female reproductive systems, ventral view. cs = copulum shaft, pr = prostatic reservoirs, vd = vas deferens, pe = proximate expansion of vas deferens, t = testis, o = ovary, mg = mehlis glands, v = vagina, od = oviduct. Scale bar = 150 pm.

DISCUSSION Among the ancyrocephahd species recorded from tetraodontids, T. serendipitus appears superficially most similar to H. kusufugu, based mainly on the morphology of the tegument and the male copulatory structure. Ogawa & Egusa (1978) described another similar species, Huliotrema kurodui, from an unrelated host, the Japanese Black Sea Bream, Acanthopugrus schlegeli. In these 3 species the copulum shaft is a very thin, slightly curved, elongate structure. The base is short and thin walled, distally inflated, with a terminal opening. Neither accessory piece nor spiralhng filament are present. The copula of H. kusufugu and T. serendipitus are of similar size, but that of H. kurodui appears much smaller. However, Ogawa & Egusa’s (1978) results were based on straight line measurements and are not strictly comparable (Table I). H. kusufugu and H. kurodai share the presence of 2 prostatic reservoirs. Yamaguti (1968) reported that H. epinepheli and Pseuduncyrocephulus kulu also have 2 prostatic reservoirs. This character was not reported for T. serendipitus by Wheeler & Klassen (1988) and most other Huliotrema species appear to have a single

A. ornatus,

H. caballeroi,

H.

and H. minutum, and undetermined for H. recurvutum (Klassen, dissertation cited above). The sinistral vagina of T. serendipitus is distinctive; the vaginae of H. kusufugu and all other described species of Huliotremu being dextral. Furthermore, the distinct tegumental transverse ridges described for Thylucicleidus are, although present, extremely difficult to discern in H. kusufugu, even under oil with interference contrast. Since I have not examined other species of Huliotremu for this tegumental character, and it has not been reported in the literature, it is difficult to determine whether the indistinct ridges of H. kusufugu are homologous with those of T. serendipitus. Haliotremu kusufugu is not the first Huliotremu species for which haptoral musculature has been described. Kearn (1971) described the musculature of H. balisticus (Hargis, 1955) and discussed its functional morphology. Associated with the ventral hamuli are the “extrinsic muscles” which originate anterior to the peduncle. Another pair of muscles is directly attached to the superficial roots of the dorsal hamuh. The latter pair of muscles appears homologous with those found attached to the superficial roots of H. kusufugu. Kearn’s (197 1) extrinsic muscles appear similar to ‘ml’ of H. kusufugu (Fig. 7). Two differences are apparent. Kearn described a ring (of muscle or fibrous tissue), at the level of the peduncle, through which the extrinsic muscles pass. This ring is absent in H. kusafugu (also in H. kurodai and T. serendipitus), although I have observed this structure in other Huliotrema species (notably H. bodiuni). Furthermore, Kearn (1971) described the extrinsic muscle (actually its tendinous extension) as passing through “fibrous loops” attached to the superficial roots of the ventral hamuli. If Kearn’s (1971) fibrous loops and the nephroids are

782

G. J. KLASSEN

FIGS. 9-l 1. Huliotrema kusujiigu new species, male reproductive structures. 9: mc = male copulatory apparatus, prl-2 = prostatic reservoirs. 10: male copulatory apparatus, cp = copulum pore, cs = copulum shaft, cb = copulum base. 11:origin of vas deferens, t = testis, pc = proximal constriction and pe = proximal expansion ofvas deferens. Scale bar = 25 pm.

A new species of Haliowema from a puffer fish

homologous (Kearn, pers. comm.), then ‘ml’ + ‘m3’ may represent the extrinsic muscles and their tendons. This would, however, require reinterpretation of the function of these muscles. In H. kusufugu ‘ml’ inserts on the lateral surface of the nephroids (which do not appear to be attached to the ventral hamuli). It is ‘m2’, the analogue to Kearn’s (1971) muscles attaching to the superficial roots of the dorsal hamuli, which inserts on the surface of the superficial roots of the ventral hamuli (Fig. 7). Although Kearn (1971) described such a muscle for the dorsal hamuli, the homologue of ‘m2’ is missing from his description for H. balisticus. According to this interpretation, ‘ml’ has no direct contact with the hamuli but instead, it appears to act on the ventral transverse bars through ‘m4’. These observations indicate that further study of the haptoral musculature may provide some fruitful and as yet unexpected results for the understanding of both the taxonomic relations and functional morphology of Haliotrema species. Thus, although H. kusajiigu is clearly distinct from other species of Haliotrema its degree of relatedness to other taxa is far from resolved. Ogawa & Egusa (1978) considered Haliotrema kurodai to most closely resemble members of Young’s (1968) species group 6 (H. chrisostomi, H. jetiS and H. lethrini), possibly based on the copulum morphology [Young (1968) described his group 6 as having a copulum with inflated base and without accessory piece]. In addition, they described H. kurodai as having only six pairs of marginal hooks in the same arrangement as H. johni and H. chrysotaeniae [members of Young’ (1968) group 21. Finally, they saw the closest resemblance between H. kurodai and Paperna’s (1972) Placodiscus acanthopugri. Clearly both specific and generic revisions are called for. Acknowledgements-I am deeply indebted to Dr K. Ogawa for his generous donation of the material described in this manuscript. I also thank Drs K. Ogawa and G. Kearn for reviewing a previous version of the manuscript. I would particularl) like to thank Dr G. Kearn for his frank and open discussion of functional morphology of the haptoral musculature; I acknowledge that my interpretations based on the material examined are not entirely consistent with those of Dr Kearn. I further thank the staff of the Fisheries Laboratory, University of Tokyo, Shizuoka Prefecture and Mr. S. Shinagawa, Hagi, Yamaguchi Prefecture for providing the host fishes. This research was funded in part by Natural Sciences and Engineering Research Council (Canada) Doctoral and Post-Doctoral Fellowships and the Ito Foundation for the Advancement of Ichthyology (Japan).

783 REFERENCES

CABALLEROy CABALLERO E., BRAVO-H• LLISM. & GROCOTT R. G. 1955. Helmintos de la Republica de Panama. XIV. Trematodos monogeneos y digeneos de peces marinos de1 Ocean0 Pacific0 de1 Norte, con description de nuevas formas. Annales del Institute Biologico de1 Universidad National Autonom de Mexico, Series Zoologica 26: 117147. DEKKERSW. J. 1975. Review of the Asiatic freshwater puffers of the genus Tetraodon Linnaeus, 1758 (Pisces, Tetraodontiformes, Tetraodontidae). Bijdragen Tot De Dierkunde 45: 87-142. HARGIS JR W. Monogenetic trematodes of Gulf of Mexico fishes. Part II. The superfamily Gyrodactyloidea (continued). Journal of Parasitology 41: 185-193. KEARN G. C. 1971. The attachment of the ancyrocephalid monogenean Haliotrema balisticus to the gills of the trigger fish, Balisres capriscus (= carolinensis). Parasirology 63: 157-162. KLASSEN G. J. 1991. Revision of Haliotrema species (Monogenea: Ancyrocephalidae) from Atlantic boxfishes (Tetraodontiformes: Ostraciinae): morphology, morphometrics, and distribution. Canadian Journal of Zoology 69: 2523-2539. OGAWA K. 1991. Redescription of Heterobothrium terrodonis (Goto, 1894) (Monogenea: Diclidophoridae) and other related new species from puffers of the genus Takifugu (Teleostei: Tetraodontidae). Japanese Journal of Parasirology 401 388-396. OGAWA K. & EGUSA S. 1978. Haliotrema kurodai n. sp. (Monogenea, Dactylogyridae, Ancyrocephalinae), a monogenean parasite obtained from the Japanese Black Sea bream, Acanthopagrus schlegeli (Bleeker). Bulletin of rhe Japanese Sociery for ScientiJic Fisheries 44: 1329-1332. PAPERNA I. 1972. Monogenea of Red Sea fishes. III. Dactylogyridae from littoral and reef fishes. Journal of Helminthology 46: 47-62. TYLER J. C. 1980. Osteology, phylogeny and higher classification of the fishes of the order Plectognathi (Tetraodontiformes). National Oceanographic and Atmospheric Administration, Technical Report, National Museum of Fisheries Sciences, Circular No. 434. WHEELER T. A. & KLASSEN G. J. 1988. Thylacicleidus serendipitus n.gen., n.sp. (Monogenea: Ancyrocephalidae) from the Indonesian freshwater puffer Tetraodonjuviatilis (Tetraodontiformes: Tetraodontidae). Canadian Journal of Zoology 66: 1928-1930. YAMAGUTI S. 1968. Monogenetic trematodes of Hawaiian fishes. University of Hawaii Press, Honolulu. YOUNG P.C 1968. Ten new species of Haliotrema (Monogenoidea: Dactylogyridae) from Australian fish and a revision of the genus. Journal of Zoology (London) 154: 41-74.