Phyllodistomum vaili, Ho, Hei Wa, Bray, Rodney A., Cutmore, Scott C., Ward, Selina & Cribb, Thomas H., 2014

Ho, Hei Wa, Bray, Rodney A., Cutmore, Scott C., Ward, Selina & Cribb, Thomas H., 2014, Two new species of Phyllodistomum Braun, 1899 (Trematoda: Gorgoderidae Looss, 1899) from Great Barrier Reef fishes, Zootaxa 3779 (5), pp. 551-562 : 554

Phyllodistomum vaili n. sp.

( Fig. 2 , 4 )

Syn. Phyllodistomum sp. 3 of Cutmore et al. (2013)

Type-locality: Off Lizard Island, northern Great Barrier Reef (14°40'S 145°27'E).

Type-host: Mulloidichthys vanicolensis (Valenciennes) , Yellowfin goatfish ( Perciformes : Mullidae ).

Other host: Mulloidichthys flavolineatus (Lacepède) , Yellowstripe goatfish ( Perciformes : Mullidae ).

Site in host: Urinary bladder.

Prevalence: M. vanicolensis 2 of 2 (100%); M. flavolineatus 10 of 11 (91%).

Type material: Holotype QM G234219; Paratypes QM G234220–234233.

Etymology: This species is named for Dr Lyle Vail, Co-Director, with Dr Anne Hoggett, of the Lizard Island Research Station and a strong supporter of our work over many years.

Description: (Measurements are of 14 gravid, unflattened specimens) Body spatulate, 1,498–2,303 (1,841) × 409–681 (549). Forebody narrow and tapering, 515–881 (686) long, occupying 35.1–39.3 (37.2)% of body length. Hindbody with 4–6 relatively weak marginal undulations on each side; marginal undulations produced by distinct lateral muscular loops, most pronounced in largest specimens. Body length to width ratio 1: 2.85–3.85 (3.37). Oral sucker opening subterminally, 137–208 (164) × 128–201 (155). Intestinal bifurcation midway between oral and ventral suckers. Ventral sucker usually slightly smaller than oral sucker, 119–183 (145) × 95–175 (141). Oral sucker width to ventral sucker width ratio 1: 0.74–1.12 (0.91). Pharynx absent. Oesophagus 147–376 (234) long. Caeca simple, blind tubes terminating 124–516 (225) from posterior extremity. Testes almost entire and smooth but with occasional slight indentations, oblique, in mid-body; anterior testis 80–192 (143) × 60–183 (122); posterior testis 67–211 (150) × 61–175 (127). Genital pore median, 49–191 (103) anterior to ventral sucker. Seminal vesicle saccular, bipartite, extends from dorsal to ventral sucker to directly dorsal to genital pore; posterior chamber large, running anteriorly then constricting to smaller more ventral anterior chamber. Prostatic chamber and surrounding cells ventral to anterior chamber of seminal vesicle. Ovary subcircular, almost entire but with occasional small indentations, postero-sinistral to ventral sucker and anterior-sinistral to testes, 51–155 (101) × 49–132 (81). Vitelline lobes entire with slightly irregular outline; left lobe immediately posterior to and occasionally overlapped by ovary, 52–93 (74) × 51–83 (54); right lobe 49–125 (78) × 33–81 (53). Laurer’s canal not detected. Uterus almost entirely intracaecal in hindbody, in extensive coils extending just posterior to ends of intestinal caeca. Eggs 27–50 (41) × 14–29 (22). Excretory vesicle tubular; anterior extent obscured by uterus in all specimens. Excretory pore dorsally subterminal, close to posterior end of body.

Figures

FIGURES 1 – 2. 1. Phyllodistomum hoggettae n. sp. from Plectropomus leopardus, ventral (Holotype QM G 234189). 2. Phyllodistomum vaili n. sp. from Mulloidichthys vanicolensis, ventral (Holotype QM G 234219). Scale bars: 1, 1 mm; 2, 500 µm.

FIGURES 3 – 4. 3. Phyllodistomum hoggettae n. sp. from Plectropomus leopardus, terminal genitalia (Paratype QM G 234194). 4. Phyllodistomum vaili n. sp. from Mulloidichthys vanicolensis, terminal genitalia (Paratype QM G 234221). ACSV—anterior chamber seminal vesicle; GP—genital pore; PCSV—posterior chamber seminal vesicle; PP—pars prostatica; U—uterus. Scale bars: 1, 2 100 µm.