Phthinomita symplocos, Nolan & Cribb, 2006

Nolan, Matthew J. & Cribb, Thomas H., 2006, An exceptionally rich complex of Sanguinicolidae von Graff, 1907 (Platyhelminthes: Trematoda) from Siganidae, Labridae and Mullidae (Teleostei: Perciformes) from the Indo-west Pacific Region, Zootaxa 1218 (1), pp. 1-80 : 35-38

Phthinomita symplocos n. sp. ( Figs. 8 , 15–22 )

Type host: Siganus lineatus (Valenciennes) , Goldlined Rabbitfish ( Perciformes : Siganidae ).

Site in host: Intertrabecular spaces of ventricle (heart).

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

Material examined: ex S. lineatus, Lizard Island (QLD), May 2004, twenty­seven specimens (Holotype no. QM G 225528 ; Paratype nos. QM G 225529–225537 ) (another three specimens used for scanning electron microscopy and nineteen specimens sequenced for ITS2) .

Collector: M.J. Nolan.

Etymology

Specific name “ Symplokos ” (Gr. interwoven, involved), for the host­parasite system described here.

Description

Based on 27 whole mounts. With features of genus. Body slightly notched at male genital pore. Vestigial oral sucker bearing 5 concentric rows of fine spines. Intestine; posterior caeca irregular, distal portions expanded. Anterior testis originating posterior to intercaecal field, margins lobed, containing dorso­ventral muscle fibres. Posterior testis elliptical, margins lobed, rudimentary (may have sperm anteriorly, testis tissue posteriorly (see Figure 8a )). Vas deferens seen antero­dextral to posterior margin of anterior testis; duct from posterior testis passing antero­medially. Cirrus­sac tear­shaped. Internal seminal vesicle ovoid, occupying posterior of cirrus­sac; ejaculatory duct sinuous; prostatic cells not seen. Ovary spherical to ovoid, slightly overlapping posterior margin of anterior testis. Oviduct originating at posterior dorsal margin of ovary, dorsal to vas deferens, entering oötype postero­dorsally. Vitelline duct forming anterior to cirrus­sac, posteriorly dextral to vas deferens and cirrus­sac. Oötype ovoid. Mehlis’ gland extending anteriorly to posterior margin of cirrus­sac, extending posteriorly to anterior margin of posterior testis. Uterus extending from oötype sinuously, sinistral to oviduct. Uterine chamber forming posterior to posterior margin of ovary, sinuous, curving dorsally posteriorly to female pore. Vitelline follicles extending anteriorly past intestinal bifurcation, sinistral and dextral to oesophagus, posterior caeca and anterior testis, posteriorly extending to mid­section of uterine chamber.

Remarks

There are 7–35 base differences (1.9–10.7% sequence divergence) between the ITS2 rDNA sequence of P. symplocos n. sp. and the remaining Phthinomita species sequenced here. Between the sequences from P. symplocos from S. lineatus off Lizard Island (15 replicates) and P. munozae n. sp. from C. venustus off Heron Island (four replicates) there are seven bases different.

Figures

FIGURE 8. Intraspecific variation in shape and size of second posterior testis from two comparatively sized specimens of Phthinomita symplocos n. sp. Scale­bars: 100 m.

FIGURES 15–17. Phthinomita symplocos n. g., n. sp. from the intertrabecular spaces of the ventricle (heart) of Siganus lineatus off Lizard Island. 15. Adult. Lateral view, whole mount. 16. Male terminal genitalia, lateral view. 17. Female terminal genitalia, lateral view. Scale­bars: 15, 250 m; 16,17, 100 m.

FIGURES 18–22. Phthinomita symplocos n. g., n. sp. 18. Whole mount, lateral view. 19,20. Vestigial oral sucker bearing 5 concentric rows of fine spines. 21. Tegumental spines in incomplete transverse rows; spines covered in tegument or mucus. Run entire length of the body. 22. Disturbed tegumental layer showing uncovered tegumental spines. Scale­bars: 18, 100 m; 19–21, 1 m; 22, 10 m.