Phthinomita littlewoodi, 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 : 50-52

Phthinomita littlewoodi n. sp. ( Figs. 38–40 )

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

Other hosts: S. corallinus (Valenciennes) , Coral Rabbitfish ( Perciformes : Siganidae ).

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

Type locality: Heron Island, southern Great Barrier Reef (23°27’S 151°55’E), Queensland .

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

Material examined: ex S. lineatus, Heron Island (QLD), Apr. 2001, Feb. 2002, May. 2003, fifteen specimens (Holotype no. QM G 225607; Paratype nos. QM G 225608–225611); ex S. corallinus, Lizard Island (QLD), Aug. 2002, May 2004, six specimens (Paratype no. QM G 225612).

Collector: M.J. Nolan.

Etymology

Specific name for Dr Timothy Littlewood of the Natural History Museum, London, in honour of his contributions to the field of platyhelminth phylogenetics.

Description

Based on 21 whole mounts. With features of genus. Body not curving dorsally posteriorly, slightly notched at male pore. Intestine; posterior caeca irregular in outline, distal extremities expanded. Anterior testis originates posterior to posterior caeca, margins lobed. Posterior testis elliptical, margins lobed. Cirrus­sac tear­shaped to spherical. Internal seminal vesicle spherical or ovoid, occupying centre of cirrus­sac; ejaculatory duct sinuous; prostatic cells not seen. Ovary ovoid to spherical, posterior to posterior margin of anterior testis, medial. Oviduct originating at centre of posterior margin of ovary. Vitelline duct forming posterior to posterior margin of ovary, sinuous; vitelline reservoir forming anterior to anterior margin of cirrus­sac, convoluted, entering oötype postero­dorsally. Oötype spherical, medial. Mehlis’ gland extending anteriorly to posterior margin of cirrus­sac, extending posteriorly to anterior margin of posterior testis. Uterus extending from oötype, sinuous. Uterine chamber forming posterior to posterior margin of ovary, straight, thin. Vitelline follicles extending anteriorly past intestinal bifurcation, extending posteriorly past posterior margin of uterine chamber, filling intercaecal field, posteriorly passing medially.

Remarks

Phthinomita littlewoodi agrees well with the characters of Phthinomita and is distinguished by having the combination of a body 2993–4133 (3465) x 64–122 (94) with only a slight notch level with the male genital pore (by comparison to that of P. brooksi ), an oesophagus that extends 24–42% of the body length, an anterior testis that is positioned posteriorly to the posterior caeca and occupies 16–31% of the body length, an anterior testis 4.4–12.4 times longer than the posterior testis, a tear­shaped cirrus­sac, a uterine chamber 107–161 (127) long and vitelline follicles that extend anteriorly past the intestinal bifurcation.

There are in addition, 1–33 base differences (0.3–10.0% sequence divergence) between the ITS2 rDNA sequence of P. littlewoodi and the remaining Phthinomita species sequenced here.

Figures

FIGURE 38. Phthinomita littlewoodi n. sp. from the intertrabecular spaces of ventricle (heart) of Siganus lineatus off Heron Island. Adult. Lateral anteriorly, medially twisting dorso­ventrally at level of “arrow a”, dorsal posteriorly, whole mount. Scale­bar: 250 m.

FIGURES 39–40. Phthinomita littlewoodi n. sp. 39. Male terminal genitalia, lateral view. 40. Female terminal genitalia, dorsal view. Scale­bars: 39, 100 m; 40, 250 m.