Rhipidocotyle labroidei, Jones & Grutter & Cribb, 2003

Jones, Conor M., Grutter, Alexandra S. & Cribb, Thomas H., 2003, Rhipidocotyle labroidei n. sp. (Digenea: Bucephalidae) from Labroides dimidiatus (Valenciennes) (Labridae), Zootaxa 327 (1), pp. 1-5 : 2-4

Rhipidocotyle labroidei n. sp. ( Fig. 1 )

Type­host: Labroides dimidiatus (Valenciennes) , Labridae .

Site: Rectum.

Type­locality: 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 222412­6 .

Description. Based on 4 adult and 3 immature heat­fixed specimens. Body fusiform, covered in small spines. Total length 217–553 (422). Widest point near mouth, just posterior to mid­body, 84–130 (109). Rhynchus horseshoe­shaped, hooded, opens ventrally, 31–74 (44) x 31–69 (54); shape varies between life and preservation, appears retracted in heat­fixed 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 mid­body, 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). Cirrus­sac medial to dextral, runs posteriorly from level of pharynx 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 tear­shaped 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 cirrus­sac, 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 cold­fixed 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 <0.05, n 1 =4, n 2 =9).

Figures

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