Syst Parasitol (2009) 74:59–63 DOI 10.1007/s11230-009-9202-x A new species of Triloculotrema Kearn, 1993 (Monogenea: Monocotylidae) from a deep-sea shark, the blacktailed spurdog Squalus melanurus (Squaliformes: Squalidae), off New Caledonia Jean-Lou Justine Received: 17 March 2009 / Accepted: 19 May 2009 Ó Springer Science+Business Media B.V. 2009 Abstract Triloculotrema chisholmae n. sp. is described from three specimens collected from the nasal tissues of a deep-sea shark, the blacktailed spurdog Squalus melanurus Fourmanoir & Rivaton, caught off New Caledonia, South Pacific. The new species is distinguished from the only other and typespecies of the genus, T. japanicae Kearn, 1993, by the morphology of the sclerotised male copulatory organ (shorter and straight versus curved) and shorter hamuli. Résumé Triloculotrema chisholmae n. sp. est décrit à partir de trois spécimens récoltés dans les tissus nasaux d’un requin de profondeur, l’aiguillat à queue noire Squalus melanurus Fourmanoir & Rivaton, pêché au large de la Nouvelle-Calédonie, Pacifique Sud. La nouvelle espèce est distinguée de l’espècetype et seule autre espèce du genre, T. japanicae Kearn, 1993, par la morphologie de l’appareil copulateur mâle sclérifié (plus court, et droit au lieu de courbe), et par des hamuli plus courts. J.-L. Justine (&) 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: justine@ird.nc Introduction Triloculotrema Kearn, 1993 was erected for the monotypic T. japanicae Kearn, 1993 from the Japanese topeshark Hemitriakis japanica (Müller & Henle). I describe here the second species of this genus, from the blacktailed spurdog Squalus melanurus Fourmanoir & Rivaton. This shark has been recorded only from the deep-sea in a few locations in the South Pacific: mainly off New Caledonia (including the Chesterfield Islands), Vanuatu and north of the Norfolk Ridge (Froese & Pauly, 2009; Séret, pers. comm). Materials and methods A single male specimen of Squalus melanurus (length 650 mm, weight 1 kg) was caught by fishermen on October 23, 2008, off the barrier reef of Nouméa, near Passe de Dumbéa, at a depth of 350 m and brought back alive in a large icebox. The shark was killed by neural pithing and examined for monogeneans minutes after death. A single hexabothriid (not studied here but deposited in the Muséum National d’Histoire Naturelle (MNHN) collections in Paris as MNHN JNC2719H1) was found on the gills and three specimens of a species of monocotylid were found in the nasal tissues. They were flattened in cold ethanol, stained with carmine and processed as described in Justine (2005). Drawings were made using an 123 60 Olympus BH2 microscope equipped with a drawing tube and differential interference contrast (DIC) optics. Measurements were made from pencil drawings with the help of a custom-made transparent rule, previously calibrated with a stage micrometer. Drawings were scanned and redrawn on a computer with Adobe Illustrator. All measurements are given in micrometres for the holotype (h) and the paratypes (p). The terminology follows Chisholm & Whittington (1999). Triloculotrema chisholmae n. sp. Type-host: Squalus melanurus Fourmanoir & Rivaton. Type-locality: Off Nouméa, New Caledonia, deep-sea. Site: Nasal tissues. Type-material: Holotype, MHNH JNC2719M2, 23.x.2008, off Nouméa, New Caledonia; 2 paratypes, same date and locality, MNHN JNC2719M1 & M3. Etymology: Named for Dr. Leslie Chisholm, the wellknown expert on monocotylids. Description (Figs. 1, 2) [Based on 3 specimens. The holotype is the only specimen clearly showing the internal genital anatomy and the haptor, but the body is damaged; paratype JNC2719M1 is in good condition but the haptor is not well oriented; paratype JNC2719M3 is laterally oriented.] Body excluding haptor h 1,350, p 930, 1,150 long, including haptor h 1,720, p 1,100, 1,300 long, h 520, p 350, 675 wide at level of ovary (Fig. 1A). Anterior glands indistinct, form 2 anterior fields. No pigment granules seen on head. Pharynx elongate, p 200 long, 125 wide. Two intestinal caeca, inconspicuous, end posterior to testis. Haptor subcircular, h 370 long, h 380 wide (Fig. 1A). Single pair of hamuli, h 155, 156, p 150–165 in length. Blade of hamuli with characteristic change in curve just before point (Fig. 1E). Ventral side of haptor with three inconspicuous loculi, with one situated between hamuli and other two lateral to each hamulus. Fourteen marginal hooklets (Fig. 1F), each 15–16 in length, with two pairs between hamuli and five pairs on lateral borders of haptor. Male copulatory organ (MCO) (= penis sclerite of Kearn, 1993) length h 42, p 40, 41, maximum width in anterior extremity h 14, p 19, 22. Ejaculatory bulb (= muscular bulb of Kearn) h 40, p 45, 50 in 123 Syst Parasitol (2009) 74:59–63 diameter, with lateral muscles attached to base of bulb (Fig. 1C). Ejaculatory bulb also with 2 posteriorly directed digitiform muscular processes (Fig. 1B– D) protruding on either side of MCO; aspect of processes changes with orientation. Testis posteriorly situated, inconspicuous, diameter ca. 200. Vas deferens arises from antero-sinistral region of testis, passes anteriorly and enters ejaculatory bulb laterally (Figs. 1A, B; 2). Ovary (Figs. 1, 2) anterior to testis, encircles right intestinal caecum dorsoventrally and narrows to form oötype. Oötype long, convoluted, forms descending and ascending limbs with regular diameter and ends in wider anterior sac, located just posterior to MCO. Mehlis’ gland located to both right and left of proximal part of oötype. Vaginal pores open at level just posterior to oötype sac; lateral branches from each pore fuse together to form posteriorly directed duct which connects ventrally with proximal part of oötype. Egg unknown; shape of oötype sac suggests tetrahedral egg. Vitellarium conspicuous, extends from mid-level of pharynx to posterior region of body proper, occupies most of body proper. Transverse vitelline ducts not seen. Remarks on generic diagnosis Triloculotrema Kearn, 1993 is characterised by the presence of three loculi. However, it must be emphasised that the loculi are not easily seen in the material examined and their limits are only suggested by smooth parts of the haptoral surface in the centre of the haptor and around each hamulus. Euzet (pers. comm) examined slides and scanning electron micrographs made by Neifar of Triloculotrema sp. from Tunisia (see below) and found that the three loculi were also very indistinct in this material. Chisholm et al. (1995) provided a phylogeny for the Monocotylidae and a revised diagnosis of Triloculotrema. The new species corresponds to all seven characters listed in their diagnosis, except for one, the presence of eye-spots. Kearn (1993) mentioned only ‘‘scattered pigment granules (eye pigment?)’’, but Chisholm & Whittington (1999) claimed that eye pigment was present ‘‘in the form of dispersed pigment granules’’ anterodorsal to the pharynx. This might be a variable character in the genus. The presence of eye pigment is also not constant in Empruthotrema Johnston & Tiegs, 1922 (Chisholm & Whittington, 1999). Syst Parasitol (2009) 74:59–63 61 b vd b d d B mco m m d d mco C b d d D A, 1000 µm; B-E, 100 µm; F, 50 µm mco F A E Fig. 1 Triloculotrema chisholmae n. sp. A, Composite drawing, ventral view, from holotype (genital anatomy and haptor) and one paratype (body); B–D, Male reproductive structures; E, Hamulus (the arrow on hamulus shows a change in the curvature of the blade, which is regularly seen); F, Marginal hooklets. (B, E, F, holotype; C, D, paratypes.) Abbreviations: b, ejaculatory bulb, d, digitiform muscular process lateral to the male copulatory organ, m, muscles, mco, male copulatory organ, vd, vas deferens Differential diagnosis There is a single other species in the genus, T. japanicae, for which information is available only for the two specimens used for the original description (OD) and two specimens collected from Mustelus antarcticus off Tasmania and described by Chisholm & Whittington (1999) (CW). T. chisholmae n. sp. can be 123 62 Syst Parasitol (2009) 74:59–63 Ejaculatory Bulb Male Copulatory Organ Digitiform Muscular Processes Anterior Sac of Oötype Vas deferens Vaginal Pore Vaginal Branch Duct from Vagina to Oötype Mehlis’ Gland Proximal Part of Oötype Ascending Limb of Oötype 500 µm Descending Limb of Oötype Ovary Right Caecum Fig. 2 Triloculotrema chisholmae n. sp. Reproductive organs, holotype, dorsal view. Vitellarium not shown distinguished from T. japanicae by the morphology of the sclerotised MCO, which is straight (versus curved in T. japanicae). The MCO is also shorter (40–42 lm) in T. chisholmae compared with T. japanicae (60–64 (OD) or 73–78 (CW) lm), as are the hamuli (150–165 vs. 229–248 (OD) or 232–268 (CW) lm). The two digitiform muscular processes associated with the MCO in T. chisholmae were not mentioned in T. japanicae by Kearn (1993), or by Chisholm & Whittington (1999), and might represent an additional difference between the two species. Discussion Triloculotrema japanicae was described from the triakid Hemitriakis japanica (Müller & Henle) off Japan. Since its description, it has been recorded only once, i.e. from the triakid Mustelus antarcticus 123 (Günther) off Tasmania (Chisholm & Whittington, 1999). The specific name has sometimes been spelled ‘japanica’ (Chisholm et al., 1995; Chisholm & Whittington, 1999), but this was a typographic error (Chisholm, pers. com.). An undescribed species has also been found in the triakid Mustelus punctulatus Risso off Tunisia, and a sequence of its 28S DNA was deposited in GenBank (AF387512) but not used in the phylogenetic analysis of Justine et al. (2002). In addition, a species, identified as ‘Triloculotrema sp. or Squalotrema sp.’, has been recorded from the nasal cavities of the etmopterid Etmopterus spinax (Linnaeus) off Norway (Klimpel, Palm & Seehagen, 2003). In all these cases, species of Triloculotrema were found in the nasal tissues. Chisholm & Whittington (1998) suggested that the reduction of haptoral loculi in Triloculotrema could be related to a special microhabitat in the nasal tissues. Syst Parasitol (2009) 74:59–63 Previous confirmed records of Triloculotrema spp. are only from triakids. T. chisholmae is the first Triloculotrema species recorded from a squalid. Whittington & Chisholm (2003) estimated that sampling biases could be one of the reasons why monogeneans were relatively rarely reported from sharks and that the nasal tissues are probably among the sites less frequently examined than the gills. Deep-sea sharks are certainly even less frequently examined than coastal species. Species of Triloculotrema appear to be limited to deep-sea sharks, either triakids or squalids (possibly etmopterids) and have a worldwide distribution (from the North Pacific to the South Pacific, plus the Mediterranean Sea); it is likely that other species will be discovered in the nasal tissues of previously unexamined deep-sea sharks. In New Caledonian waters, recorded monocotylids include only the four species, Decacotyle octona (Young, 1967) Chisholm & Whittington, 1998, D. elpora Marie & Justine, 2005, Clemacotyle australis Young, 1967 and Thaumatocotyle pseudodasybatis Hargis, 1955, all from the spotted eagle ray Aetobatus cf. narinari (see Marie & Justine, 2005, 2006), and records of parasites from deep-sea sharks include only trypanorhynch cestodes (Beveridge & Justine, 2006, 2007) and isopods (Trilles & Justine, 2004). This is the first monocotylid from a shark and the first monogenean from a deep-sea shark recorded from off New Caledonia. Acknowledgements Jean-Raymond Olivier generously provided the live shark. Parasites were collected by Ian Whittington, Elisabeth Perkins and Vanessa Glennon, during a visit to New Caledonia, and by Isabelle Mary. Cyndie Dupoux skilfully prepared the slides. Bernard Séret (IRD, Paris) identified the shark (from photographs) and provided information on its geographical distribution. Leslie Chisholm (SAM, Adelaide) thoroughly edited a draft of the manuscript. References Beveridge, I., & Justine, J.-L. (2006). Gilquiniid cestodes (Trypanorhyncha) from elasmobranch fishes off New Caledonia with descriptions of two new genera and a new species. Systematic Parasitology, 65, 235–249. Beveridge, I., & Justine, J.-L. (2007). Paragrillotia apecteta n. sp. and redescription of P. spratti (Campbell & Beveridge, 1993) n. comb. (Cestoda, Trypanorhyncha) from hexanchid and carcharhinid sharks off New Caledonia. Zoosystema, 29, 381–391. 63 Chisholm, L. A., Wheeler, T. A., & Beverley-Burton, M. (1995). 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