Zootaxa, Holorchis castex n. sp. (Digenea ...

Zootaxa 1426: 51–56 (2007) www.mapress.com / zootaxa/

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ZOOTAXA

Holorchis castex n. sp. (Digenea: Lepocreadiidae) from the painted sweet-lips Diagramma pictum (Thunberg, 1792) (Perciformes: Haemulidae) from New Caledonia RODNEY A. BRAY1 & JEAN-LOU JUSTINE2 1

Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD, UK. E-mail: [email protected] 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. E-mail: [email protected] 2

Abstract Holorchis castex n. sp. is described from the haemulid fish Diagramma pictum off New Caledonia. It is easily distinguished from all other species in the genus in that the vitellarium reaches well into the forebody. Its relationships with members of the genera Pseudaephnidiogenes and Aephnidiogenes are also discussed. The monorchiid Lasiotocus plectorhynchi is reported from the same host. Key words: Digenea, Lepocreadiidae, Holorchis castex n. sp., Haemulidae, Diagramma pictum, New Caledonia

Résumé Holorchis castex n. sp. est décrit de Diagramma pictum (Haemulidae) de Nouvelle-Calédonie. L’espèce est aisément distinguée des autres espèces du genre par son vitellarium qui se prolonge à l’avant du corps. Ses relations avec les membres des genres Pseudaephnidiogenes et Aephnidiogenes sont aussi discutées. Le Monorchiidae Lasiotocus plectorhynchi est signalé du même hôte.

Introduction Two species of Holorchis Stossich, 1901 have been reported from haemulids, the first being H. plectorhynchi Durio & Manter, 1968 from the yellowbanded sweetlips Plectorhinchus lineatus (Linnaeus) [as P. goldmanni (Bleeker)], off New Caledonia (Durio & Manter 1968), and the second being H. legendrei Dollfus, 1946 which, although mainly reported in mullids and sparids, was reported in the rubberlip grunt, Plectorhinchus mediterraneus Guichenot [as Diagramma mediterraneum (Guichenot)], off Senegal in the eastern Atlantic by Fischthal & Thomas (1972). Here, we report another species of Holorchis from the haemulid, the painted sweetlips Diagramma pictum (Thunberg).

Material and methods Digeneans were collected live, immediately fixed in hot seawater and then transferred to ethanol. Wholemounts were stained with Mayer's paracarmine, cleared in beechwood creosote and mounted in Canada balsam. Measurements were made through a drawing tube on an Olympus BH-2 microscope, using a Digicad Accepted by N. Dronen Jr: 31 Jan. 2007; published: 15 Mar. 2007

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Plus digitising tablet and Carl Zeiss KS100 software adapted by Imaging Associates, and are quoted in micrometres, with the range and the mean in parentheses. The following abbreviations are used: BMNH, the British Museum (Natural History) Collection at the Natural History Museum, London, UK; MNHN, Muséum National d’Histoire Naturelle, Paris.

Results Family Lepocreadiidae Odhner, 1905 Subfamily Lepidapedinae Yamaguti, 1958 Genus Holorchis Stossich, 1901 Holorchis castex n. sp. (Figs 1–5) Type-host: Diagramma pictum (Thunberg, 1792), Haemulidae, painted sweet-lips. Site: Digestive tract. Type-locality: Rocher à la voile, Nouméa, New Caledonia (22°18’30’’S, 166°25’50’’E, 01/06/2006). Prevalence: 1 of 1 (100%). Intensity: 6. Type-specimens: holotype MNHN JNC1848–D1, paratypes MNHN JNC1848–D2–3, BMNH 2006.12.6.40–41. Etymology: ‘Castex’ or ‘loche castex’ is the common name of the host in New Caledonia (Laboute & Grandperrin 2000). Description. Based on five specimens. Body elongate, large; 6,793–8,577 × 1,145–1,438 (7,569 × 1,317); width 16.8–18.4 (17.4)% of body-length (Figure 1). Tegument spinous to posterior extremity, sparser in hindbody. Pre-oral lobe distinct, 42–66 (51) long. Oral sucker subglobular, subterminal, with distinct groove in dorsal margin; 401–463 × 418–500 (422 × 456) (Figure 4). Ventral sucker rounded, in anterior third of body; 349–419 × 332–416 (382 × 375). Forebody 1,998–2,376 (2,149) long; 27.7–29.4 (28.4)% of body-length. Sucker-ratios: length 1:0.87–0.94 (0.91); width 1:0.79–0.86 (0.82). Prepharynx short; mainly within posterior concavity of oral sucker, reaching 0–16 (11) posterior to oral sucker. Pharynx large, doliiform; 211–288 × 218–278 (250 × 246). Pharynx: oral sucker ratio 1:1.64–1.93 (1.86). Oesophagus short; 63–225 (141) long. Intestinal bifurcation in anterior forebody, 1,230–1,505 (1,327) from ventral sucker. Caeca long, narrow, apparently terminate blindly near posterior extremity, terminations obscured by vitellarium, post-caecal distance approximately 249–440 (342). Testes 2, entire, oval, almost tandem, contiguous or slightly separated, just in anterior half of hindbody; anterior 498–652 × 407–556 (581 × 508); posterior 509–699 × 468–590 (640 × 524). Intertesticular distance 0–151 (66); 0–1.76 (0.83)% of body-length. Post-testicular distance 2,407–3,022 (2,673); 33.5–37.0 (35.3)% of body-length. External seminal vesicle long, convoluted, reaches dorsal to about mid-level of ventral sucker. Cirrus-sac oval, thick-walled with distinct layer of gland-cells between outer wall and male-duct (Figure 2). Internal seminal vesicle long, slightly undulating, with thickened muscular wall; 405–471 × 248–551 (442 × 284). Pars prostatica vesicular, subglobular, with thick wall, sparsely lined with anuclear cell-like bodies. Ejaculatory duct short, muscular, may be extended through genital pore as cirrus. Genital atrium distinct, thick-walled. Genital pore submedian, well anterior to ventral sucker. Ovary oval, entire, 349–429 × 220–323 (400 × 271); 628–894 (764) (9.59–10.8 (9.91)% of body-length) pre-testicular, separated from anterior testis by bulk of uterus, 56–136 (89) (0.73–1.58 (1.16)% of bodylength) from ventral sucker. Seminal receptacle oval, postero-median to ovary. Laurer’s canal opens dorsally

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median to ovary (Figure 5). Mehlis’ gland median to ovary. Uterus intercaecal, overlaps anterior testis, narrows at level of ovary, loops dorsally to ventral sucker. Metraterm about half length of cirrus-sac, with slightly thickened wall, runs dorsally to cirrus-sac (Figure 3). Eggs tanned, operculate, extremely numerous, 75–87 × 27–33 (80 × 31). Vitellarium follicular, fields reach well into forebody, 380–688 (542) anterior to ventral sucker, and close to posterior extremity, mainly lateral, dorsal and ventral to caeca, confluent dorsal and ventral in post-testicular region. Vitelline reservoir ventral to posterior part of ovary. Excretory pore terminal. Excretory vesicle I-shaped, passes sinistrally to posterior testis, dextrally to anterior testis, not traced beyond anterior testis, but presumably terminates somewhere dorsally to uterus.

Discussion This species keys to the genus Holorchis in Bray (2005). The three currently recognised species of Holorchis are the type-species, H. pycnoporus Stossich, 1901 from sparids and labrids in the Mediterranean Sea and northeastern Atlantic, H. legendrei (syn. H. ioannoui Brinkmann, 1967) from mullids, sparids and several other families, including a haemulid, in the Mediterranean Sea, eastern Atlantic and south-western Indian Oceans and H. plectorhynchi from a haemulid and a lethrinid off New Caledonia (Durio & Manter 1968; Bartoli & Bray 1996; Bray & Cribb 1997; Lozano et al. 2003). H. plectorhynchi was described by Durio & Manter (1968) based on 2 specimens from the haemulid Plectorhinchus lineatus and 1 immature specimen from the trumpet emperor Lethrinus miniatus (Forster) [Lethrinidae]. We have examined 3 specimens of P. lineatus from the same locality (Nouméa, New Caledonia) and found no digeneans and we have also examined 4 specimens of L. miniatus and found several digenean species, but not H. plectorhynchi. Several other species of Lethrinus have also been examined and no specimens of Holorchis have been recovered. H. castex n. sp. can be easily distinguished from all recognised Holorchis species by the extension of the vitelline fields into the forebody. The genus Pseudaephnidiogenes Yamaguti, 1971 is rather similar to Holorchis, differing only in the oblique testes and the distinct encroachment of the uterus laterally to the anterior testis. Although the testes in H. castex may be considered to be very slightly oblique and the uterus overlaps the anterior testis slightly, these conditions in members of Pseudaephnidiogenes are much more marked. Nevertheless, as the vitellarium reaches into the forebody in some members the genus, namely P. rhabdosargi (Prudhoe, 1956) and P. laciniosus Gaevskaya, 1983, a comparison has been made with these species. Pseudaephnidiogenes rhabdosargi is reported in the sparids, the goldlined seabream Rhabdosargus sarba (Forsskål) and the Cape stumpnose R. holubi (Steindachner) from the Indian Ocean off Natal and Cape Province, respectively (Prudhoe 1956; Bray 1985). The vitellarium reaches into the forebody only in the specimens from R. sarba. These differ from H. castex in body-proportions (length 1,600–3,500 × width 1,000– 1,200, i.e. width about 34–63% of body-length) and the lobed, distinctly oblique testes. Pseudaephnidiogenes laciniosus from the haemulid, the Sompat grunt Pomadasys jubelini (Cuvier) from off Angola in the southeastern Atlantic (Gaevskaya 1983), was considered a species of ‘uncertain status’ by Bray & Cribb (1997). It is the only putative Pseudaephnidiogenes species from a haemulid host and has, in common with H. castex, the vitellarium reaching into the forebody. It differs from H. castex in being relatively squat (length 1,430–2,530 × width 550–830, i.e. width about 33–38% of length), with distinctly lobed, oblique testes and small eggs (57–59 × 27–32). The genus Aephnidiogenes Nicoll, 1915 has a similar general morphology to Holorchis, in that the bulk of the uterus lies between the testes and the ovary, and is found mainly in haemulids. It is distinguished, currently even at the subfamily level, by the lack of a cirrus-sac (see Bray & Cribb 1997; Bray 2005). The diagnosis of the genus in Bray & Cribb (1997) and the subfamily in Bray (2005) state that the vitellarium reaches to the ovary, another feature distinguishing species of Aephnidiogenes from H. castex.

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FIGURES 1–5. Holorchis castex n. sp. 1. Ventral view of holotype, uterus in outline. 2. Male terminal genitalia, part of ventral sucker indicated. 3. Metraterm and terminal part of uterus, cirrus-sac and part of ventral sucker indicated. 4. Oral sucker showing dorsal groove (g). 5. Region of female proximal system, uterus in bold outline, vitellarium omitted. Abbreviations: c, caecum; Lc, Laurer’s canal; Mg, Mehlis’ gland; ov, ovary; sr, seminal receptacle; vr, vitelline reservoir; vs, ventral sucker. Scale-bars: 1, 1mm; 2, 3, 5, 200μm; 4, 100μm.


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Other parasite recorded and comments on the host We also found the monorchiid Lasiotocus plectorhynchi (Yamaguti, 1934) in the same fish. This species was originally described as Proctotrema plectorhynchi Yamaguti, 1934 from ‘Plectorhynchus pictus’ from the Inland Sea of Japan (Yamaguti 1934). The name Plectorhinchus [or erroneously Plectorhynchus] pictus has been used for two distinct species and in the recent parasitological literature it is not always clear which species is referred to. These two species are the painted sweetlips Plectorhynchus [now Diagramma] pictum (Thunberg) [originally Perca picta Thunberg] and the trout sweetlips Plectorhynchus [correctly Plectorhinchus] pictus (Tortonese) [originally Hapalogenys pictus Tortonese] (see Froese & Pauly 2006). The date of the original record of L. plectorhynchi indicates that the host referred to must be Diagramma pictum.

Conclusions The record of another member of the morphologically similar group of genera including Aephnidiogenes, Holorchis and Pseudaephnidiogenes in a haemulid, sheds doubt on the distinction at the subfamily level of the former from the latter two genera. The feature distinguishing the subfamily Aephnidiogeninae Yamaguti, 1934 is the lack of a cirrus-sac, with the prostatic cells lying unconfined in the parenchyma. We are at present exploring this relationship further, utilizing inferences from molecular sequences.

Acknowledgements Gérard Mou-Tham (IRD, Nouméa) caught the fish specimen. Géraldine Colli and Lenaïg Hemery, students, participated in the fishing operations and parasitological survey. Angelo di Matteo (IRD) provided technical help. Tom Cribb (The University of Queensland) kindly read the manuscript.

References Bartoli, P. & Bray, R.A. (1996) Description of three species of Holorchis Stossich, 1901 (Digenea: Lepocreadiidae) from marine fishes off Corsica. Systematic Parasitology, 35, 133–143. Bray, R.A. (1985) Some helminth parasites of marine fishes of South Africa: Families Gorgoderidae, Zoogonidae, Cephaloporidae, Acanthocolpidae and Lepocreadiidae (Digenea). Journal of Natural History, 19, 377–405. Bray, R.A. (2005) Family Lepocreadiidae Odhner, 1905. In: Jones, A., Bray, R.A. & Gibson, D.I. (Eds), Keys to the Trematoda. Volume 2. CABI Publishing and the Natural History Museum, Wallingford, pp. 545–602. Bray, R.A. & Cribb, T.H. (1997) The subfamily Aephnidiogeninae Yamaguti, 1934 (Digenea: Lepocreadiidae), its status and that of the genera Aephnidiogenes Nicoll, 1915, Holorchis Stossich, 1901, Austroholorchis n. g., Pseudaephnidiogenes Yamaguti, 1971, Pseudoholorchis Yamaguti, 1958 and Neolepocreadium Thomas, 1960. Systematic Parasitology, 36, 47–68. Durio, W.O. & Manter, H.W. (1968) Some digenetic trematodes of marine fishes of New Caledonia. Part II. Opecoelidae and Lepocreadiidae. Journal of Parasitology, 54, 747–756. Fischthal, J.H. & Thomas, J.D. (1972) Digenetic trematodes of marine fishes from Senegal. Bulletin de l'Institut Fondamental d'Afrique Noire, 34A, 292–322. Froese, R. & Pauly, D. (2006) FishBase: World Wide Web electronic publication. Available on http://www.fishbase.org. Gaevskaya, A.V. (1983) New species of trematodes of the family Lepocreadiidae from the south Atlantic fishes. Zoologicheskii Zhurnal, 62, 788–791. (In Russian). Laboute, P. & Grandperrin, R. (2000) Poissons de Nouvelle-Calédonie. Éditions Catherine Ledru, Nouméa, New Caledonia, 520 pp. Lozano, C., Úbeda, J.M., de Rojas, M., Ariza, C. & Guevara, D.C. (2003) Estudio de dos digénidos de la familia Lepocreadiidae (Platyhelminthes, Digenea) en la costa sur de la Península Ibérica. Boletín de la Real Sociedad Española de Historia Natural (Sec. Biol.), 98, 41–45.

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Prudhoe, S. (1956) On a new trematode from South African fishes. Annals and Magazine of Natural History, Series 12, 9, 72–75. Yamaguti, S. (1934) Studies on the helminth fauna of Japan. Part 2. Trematodes of fishes, I. Japanese Journal of Zoology, 5, 249–541.


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