Flagellotrema amphitrite, Hall, Kathryn A. & Cribb, Thomas H., 2008

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, Zootaxa 1718, pp. 1-35 : 9-12

publication ID

https://doi.org/ 10.5281/zenodo.181038

DOI

https://doi.org/10.5281/zenodo.6231270

persistent identifier

https://treatment.plazi.org/id/038287E1-FFE9-FFA4-9589-FABCA248FD36

treatment provided by

Plazi

scientific name

Flagellotrema amphitrite
status

sp. nov.

Flagellotrema amphitrite View in CoL n. sp.

( Fig. 3 View FIGURE 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 View 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 View FIGURE 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 View 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.

TABLE 3. Measurements of Flagellotrema amphitrite n. sp. All measurements are of laterally mounted specimens and are presented in micrometres (µm).

    All specimens     Mature specimens
Variable n α Mean Min Max n Mean Min Max
body length 33 1431 592 2768 17 1823 1104 2768
body width 33 401 144 800 17 523 320 800
pharynx length 33 194 77 437 17 257 109 437
pharynx width 33 142 71 263 17 177 116 263
oesophageal bulb length 33 122 64 205 17 143 109 205
oesophageal bulb width 33 141 71 212 17 164 116 212
ventral sucker length 33 232 154 327 17 255 212 327
ventral sucker width 33 206 116 321 17 236 186 321
oesophagus length 32 789 272 1395 16 974 714 1395
caeca length 32 294 141 533 16 360 205 533
length from pharynx to oesophageal bulb 33 287 135 533 17 351 231 533
length from oesophageal bulb to ventral sucker 33 529 173 995 17 672 334 995
anterior testis length 28 130 51 257 15 156 116 257
anterior testis width 28 147 58 250 15 172 109 250
posterior testis length 29 128 51 218 15 152 71 218
posterior testis width 29 139 45 250 15 167 71 250
ovary length 21 100 32 180 16 115 64 180
ovary width 20 105 45 186 15 119 64 186
seminal receptacle length 19 107 39 180 14 120 71 180
seminal receptacle width 14 77 39 103 9 82 58 103
cirrus-sac length 22 200 128 321 13 221 128 321
cirrus-sac width 22 126 77 250 13 153 90 250
egg length 17 70 61 77 17 70 61 77
egg width 17 41 35 51 17 41 35 51
papilla length 22 104 6 315 12 170 35 315
ratio β of pharynx to oesophageal bulb (length) 33 1.52 1.00 2.44 17 1.75 1.00 2.44
ratio of pharynx to ventral sucker (length) 33 0.80 0.44 1.40 17 0.99 0.44 1.40
ratio of oesophageal bulb to ventral sucker (length) 33 0.52 0.42 0.64 17 0.56 0.44 0.64
ratio of caeca to body (length) 32 0.21 0.16 0.29 16 0.20 0.16 0.25
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