Flagellotrema amphitrite Hall & Cribb, 2008, n. sp.
Creators: name: Hall, Kathryn A.
name: Cribb, Thomas H.
Publisher: name: Zenodo
Year: 2008
Subjects: Biodiversity
Taxonomy
Animalia
Platyhelminthes
Trematoda
Plagiorchiida
Gyliauchenidae
Flagellotrema
Flagellotrema amphitrite

description: Flagellotrema amphitrite n. sp.
(Fig. 3)
Type-host: Prionurus maculatus Ogilby, 1887, Acanthuridae; yellowspotted sawtail.
Site: intestine.
Type-locality: Heron Island, Great Barrier Reef, Queensland, Australia (23°27'S 151°55'E)
Prevalence: Total prevalence (P. m a c u l a t u s, Heron Island) 1 of 1 (100%).
Intensity: Data not recorded.
Deposition of specimens: Holotype QM G222219 (coll. C.B. Chambers, 16 Feb. 1999); paratypes QM G222220–222222 (coll. C.B. Chambers, 16 Feb. 1999).
Etymology: This species is named after Amphitrite, the Greek goddess of the sea. Amphitrite was believed to be a nereid and, as the wife of Poseidon, was the Queen of the Sea.
Description. Based on 33 (17 mature and 16 immature) specimens. Measurements in Table 3. Body elongate, fusiform, distinctly curved dorsoventrally; pale orange in life. Tegument smooth. Ventral sucker round, posterior, not ventrosubterminal. Pharynx pyriform, ventrosubterminal, larger than ventral sucker; fleshy preoral lip, prominent, massive. Oesophagus long, with 2 loops in figure-8 formation (Fig. 3); first loop anticlockwise, crosses midline; second loop clockwise, immediately anterior to first loop; posterior thick-walled chamber absent; invested with glands along entire length. Oesophageal bulb well-developed, spheroid, smaller than pharynx, approximately half length of ventral sucker. Intestinal bifurcation immediately posterior to oesophageal bulb; caeca 2, blind, occupy approximately 1/4 of body length; gastrodermis very thick.
Testes 2, entire, ovoid, diagonal, in posterior 1/3 of body, sometimes contiguous in mature specimens. Cirrus-sac encased in muscular capsule. Seminal vesicle partially external to cirrus-sac, bipartite; anterior portion globular, internal to cirrus-sac, connected to posterior portion via short, narrow duct, surrounded by muscular capsule contiguous with cirrus-sac; posterior portion elongate, external to cirrus-sac. Va s a e ff eren t ia arise ventromedially from testis, proceed anteriorly, unite to form vas deferens, which swells immediately into seminal vesicle. Pars prostatica large, cylindrical; prostate gland cells external to cirrus-sac, very dense. Cirrus-sac prominent, median, generally posterior to caeca, sometimes overlapping posterior margin, globular; ejaculatory duct long, convoluted within cirrus-sac, with distal expansion, eversible. Genital atrium large, regular, with cilia-like lining. Genital pore, round, at level of termination of caeca.
Ovary entire, generally intertesticular, dextral, not contiguous with testes; oviduct associated with swollen insemination chamber. Canalicular seminal receptacle prominent, saccular, posterodorsal to ovary. Mehlis’ gland anterodorsal to ovary, overlies ootype. Laurer’s canal proceeds anterodorsal from intersection of oviduct and seminal receptacle, exits immediately anterodorsal to ovary. Ootype anterior to ovary. Uterus entirely pre-ovarian, coiled in median field. Opening of uterus unspecialised, enters genital atrium sinistral to cirrussac. Vitellarium follicular; follicles restricted from level of oesophagus to immediately anterior to testes, form distinctive X-shaped distribution in ventral field, dorsal field resticted to intercaecal field; vitelline ducts proceed posterolateral from termination of fields, unite in midline to form subtriangular vitelline reservoir immediately sinistrodorsal to ovary. Eggs large, tanned, operculate, apparently unembryonated in utero.
Excretory vesicle elongate, saccular. Excretory pore subterminal, opens on prominent, large papilla. Primary collecting ducts arise anterolaterally. Lymph system not observed.
Footnotes: α number of specimens measured, β all ratios are calculated to 2 decimal places.
Molecular data. Sequence data was obtained from 1 specimen for 2 genes: Specimen 1 (P. maculatus, Heron Island): ITS2 rDNA, 28S rDNA (D1–D3). GenBank accession numbers are in Table 1.
Comments. Flagellotrema amphitrite is readily distinguished from F. convolutum by the size and shape of the pharynx and the coiling pattern of the oesophagus. The pharynx of F. amphitrite is strongly pyriform and is massive, and much larger than the oesophageal bulb. In contrast, the pharynx of F. convolutum is generally barrel-shaped, although in 1 voucher specimen the pharynx is distinctly pyriform, and only slightly larger than the oesophageal bulb. The oesophagus of F. amphitrite forms a figure-8 coil in the anterior third of the body. This double looping formation is not seen in F. convolutum; the oesophagus of F. convolutum executes only 1 clockwise loop. Despite the morphological differences between the 2 species, membership of this new species to Flagellotrema is supported by the posterior position of the cirrus-sac, which is almost entirely posterior to the caeca. In some specimens of F. amphitrite, the genital pore lies between the ends of the caeca, however, the position is more posterior than in species of the morphologically similar genus Gyliauchen. Further, in both F. convolutum and F. amphitrite, the ovary is intertesticular. The systematic position of F. amphitrite is further supported by the possession of a prominent excretory papilla in both species here attributed to Flagellotrema. The genus is united by the shared position of the cirrus-sac largely posterior to the caeca, presence of a prominent excretory papilla and the position of the ventral sucker, which although posterior, is not entirely ventrosubterminal.
description: Published as part of Hall, Kathryn A. & Cribb, Thomas H., 2008, Revision of Flagellotrema Ozaki, 1936 (Digenea, Gyliauchenidae Fukui, 1929), including the description of two species from acanthuroid fishes from the Great Barrier Reef, Queensland, Australia, pp. 1-35 in Zootaxa 1718 on pages 9-12, DOI: 10.5281/zenodo.181038