zootaxa

Zootaxa 327: 1–5 (2003) www.mapress.com/zootaxa/

ISSN 1175-5326 (print edition)

Copyright © 2003 Magnolia Press

ISSN 1175-5334 (online edition)

ZOOTAXA

Rhipidocotyle labroidei n. sp. (Digenea: Bucephalidae) from Labroides dimidiatus (Valenciennes) (Labridae) CONOR M. JONES1, ALEXANDRA S. GRUTTER1 & THOMAS H. CRIBB2 1

School of Life Sciences, University of Queensland 4074, Australia. [email protected] [email protected] 2 Centre for Marine Studies and the Department of Microbiology and Parasitology, University of Queensland 4074, Australia. [email protected]

Abstract Rhipidocotyle labroidei n. sp. is described from the rectum of cleaner fish, Labroides dimidiatus (Labridae), on the Great Barrier Reef. R. labroidei differs from its congeners by the combination of its small size, anteriorly directed caecum, the shape and positioning of its gonads, and by its posteriorly confined uterus. We have found Rhipidocotyle in species of Labroides from New Caledonia and Moorea that differ from the described material in the size of eggs, but these worms are not suitable for description. We suggest there are at least two species of Rhipidocotyle in Labroides spp. from the tropical Pacific. Key words: Great Barrier Reef, fish parasites, new species

Introduction Cleaner fish such as Labroides dimidiatus (Valenciennes) and L. bicolor Fowler & Bean, feed by removing parasites, mucus and host tissues from external surfaces of teleosts and elasmobranchs (Randall, 1958; Keyes, 1982; Grutter, 1996; 1997b). Several surveys of gut contents have investigated ectoparasite consumption by L. dimidiatus (Choat, 1969; Grutter, 1996; 1997a; 1997b; 2000), however, no studies have investigated its parasitic fauna. Randall (1958) refers to “tiny digenetic flukes” in L. bicolor, yet these remain undescribed. Here we report a species of the bucephalid genus Rhipidocotyle Diesing. Although larval bucephalids have been reported from wrasses by many authors (Carrère, 1938; Campos & Carbonell, 1993; Costello et al., 1995; Korniichuk 2001), this report is only the third record of an adult bucephalid found in wrasses. Prosorhynchus aculeatus Odhner has been found in the Mediterranean wrasses Symphodus tinca (Linnaeus) and S. mediterraneus (Linnaeus) by Papoutsoglou (1976). Accepted: 7 October 2003; published: 15 October 2003

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Materials and Methods

327 Labroides dimidiatus were collected from shallow (2–8m) reefs off Lizard Island and Heron Island, Great Barrier Reef, Australia, during January and March-April 2002. A SCUBA diver equipped with a hand net herded fish into barrier nets (Grutter, 1997). Fish were pithed and the digestive tract was removed and opened length-wise in a solution of 0.85% saline. A gut-wash was performed to dislodge any parasites. Worms were heatfixed in boiling saline and preserved in 10% formalin immediately. Worms were stained using Mayer’s haematoxylin, dehydrated with a graded series of alcohols, cleared in cedar wood oil, and mounted in Canada balsam. L. dimidiatus and L. bicolor preserved whole in 10 % formalin from New Caledonia (22°16’S, 166°27’E) (from Grutter 1999) and from Moorea in French Polynesia (17°33’S, 149°37’W) (Grutter unpublished data) were also dissected. Worms from these fish were stained and mounted without heat fixation and are referred to below as cold-fixed. These cold-fixed worms were unsuitable for description because they were often contracted, misrepresenting the shape of the worm and its organ arrangement. However, it was clear that all worms were Rhipidocotyle. Because egg size is not affected by fixation method we used this to identify possible species differences within the samples. Ten of the largest and most appropriately oriented eggs were measured (micrometres) from each mature worm. Differences in the average egg length from 9 worms from L. bicolor from Moorea were compared with eggs from 4 worms included in the described material using a Mann-Whitney U-test with unequal replication. Eggs from worms with very few eggs were not measured because their eggs were small and misshapen.

Results Family Bucephalidae Poche, 1907 Genus Rhipidocotyle Diesing, 1858 Rhipidocotyle labroidei n. sp. (Fig. 1) Type-host: Labroides dimidiatus (Valenciennes), Labridae. Site: Rectum. Type-locality: Lizard Island Australia (14° 40’S, 154° 20’E). Prevalence: 56% (10/18). Intensity: mean 1.5, range 1–8. Other Localities: Heron Island Australia (23° 27’S, 151° 55’E), Prevalence: 47% (8/ 17). Intensity: mean 1.24, range 1–5. Deposition of specimens: Deposited in Queensland Museum collection, Holotype QM G 222411, Paratypes QM G 222412-6. 2

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JONES ET AL.

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FIGURES 1 & 2. 1, Rhipidocotyle labroidei n. sp. ex Labroides dimidiatus, from Lizard Island, ventral view; 2, cold-fixed Rhipidocotyle sp. from the rectum of L. bicolor off Moorea in ventral view. Scale bars 100µm.

Description. Based on 4 adult and 3 immature heat-fixed specimens. Body fusiform, covered in small spines. Total length 217–553 (422). Widest point near mouth, just posterior to mid-body, 84–130 (109). Rhynchus horseshoe-shaped, hooded, opens ventrally, 31–74 (44) x 31–69 (54); shape varies between life and preservation, appears retracted in heat-fixed specimens (figure 1), blunt lobed crown in live worms. Prepharynx 15–20 (17). Pharynx relatively large, 31–74 (44) x 28–74 (46); occupies 7.5–14.2% of total body length. Caecum simple, saccular, always directed anteriorly, 35 –73 (53) x 59–114 (81). Ovary entire, near mid-body, sinistral to medial line and anterior to testes, 23–41 (33) x 25–51 (42). Testes 2, posterior to pharynx, oval, often overlap, oblique to nearly opposite, 15–51 (32) x 23–66 (45). Cirrus-sac medial to dextral, runs posteriorly from level of phar-

RHIPIDOCOTYLE LABROIDEI N. SP.

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ynx to posterior end of body, 18–51 (32) x 66–201 (135), contains ovoid seminal vesicle 25–43 (31) x 26–53 (35), and curved pars prostatica. Genital lobe 17–33 (24) x 19–31 (25) encased by tear-shaped genital atrium 29–37 (33) x 43–88 (59). Genital pore just anteroventral to posterior end of body. Coiled uterus covers area from posterior extremity to caecum, never extending anterior to anterior end of caecum. Vitelline follicles (5–6 when individually discernible) form 2 separate, lateral groups, extend from 23–64 (40) posterior to rhynchus to anterior limit of caecum. Vitelline ducts taper to unite near ovary. Eggs 6.4– 11.2 (8.1 ± 0.2 se) x 14.4–20.8 (17.4 ± 0.25 se), smaller in worms with very few eggs. Excretory pore terminal. Excretory vesicle runs anteriorly, parallel to cirrus-sac, to level of seminal vesicle then is no longer discernible. Other Specimens. Specimens of Rhipidocotyle collected from L. dimidiatus and L. bicolor from New Caledonia and French Polynesia roughly resemble the described material in that they have a similar rhynchus, a very large pharynx, anteriorly directed caecum and posteriorly confined uterus. The best preserved cold-fixed specimen ex L. bicolor from Moorea illustrates these similarities (Fig. 2). Worms from L. bicolor from Moorea have significantly larger eggs 6.4–12 (8.9 ± 0.1 se) x 19.2–27.2 (24 ± 0.2 se) than worms ex L. dimidiatus from Lizard Island (U=0, p