Phthinomita sasali, 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 : 55-57

Phthinomita sasali n. sp. ( Figs. 44–46 )

Type host: Siganus doliatus (Cuvier) , Barred Rabbitfish ( Perciformes : Siganidae ).

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

Type locality: Palau (7°30’N 134°30’E), Indo­West Pacific Ocean .

Material examined: ex S. doliatus , Palau (Oceania), Nov. 2001, seven specimens (Holotype no. QM G 225625 ; Paratype nos. QM G 225626–225627 ) (eight specimens sequenced for ITS2) .

Collectors: R.D. Adlard, R.A. Bray, T.H. Cribb and P. Sasal.

Etymology

Specific name for our good friend and colleague Dr Pierre Sasal, for his sense of humour and his continued interest in this study.

Description

Based on five whole and two partial mounts. With features of genus. Body distinctly curving dorsally posteriorly, distinctly notched level with male genital pore. Intestine; posterior caeca irregular, distal portions expanded. Anterior testis originating posterior to posterior caeca, margins lobed, containing dorso­ventral muscle fibres. Posterior testis ovoid, margins lobed. Cirrus­sac elongate, elliptical, narrow ventrally, widening dorsally. Internal seminal vesicle ovoid, occupying ventral region of cirrus­sac; ejaculatory duct sinuous; prostatic cells small. Ovary spherical, posterior to posterior margin of anterior testis. Oviduct originating at centre of posterior margin of ovary, sinuous, dorsal to vas deferens, entering oötype postero­dorsally. Vitelline duct forming anterior to anterior margin of cirrus­sac, sinuous. Oötype ovate, dorsal to anterior margin of posterior testis and distal portion of vitelline duct. Mehlis’ gland extending anteriorly past posterior portion of distinct notch in body wall, extending posteriorly to anterior margin of posterior testis. Uterus extending from oötype, sinuous. Uterine chamber positioned posterior to posterior margin of ovary, sinuous, curving dorsally posteriorly to female genital pore. Vitelline follicles extending anteriorly past intestinal bifurcation, extending posteriorly past posterior margin of uterine chamber, anteriorly ventral and dorsal to oesophagus and intestine, filling intercaecal field, passing posteriorly medially, dextral to anterior testis and uterus posteriorly.

Remarks

Phthinomita sasali is differentiated from its congeners by possessing the combination of a body 3765–4017 (3863) x 128–176 (153) with a very distinct notch level with the male genital pore (comparable to that of P. brooksi ), an oesophagus that occupies 25–26% of the body length, and an anterior testis that is positioned entirely posterior to the posterior caeca, is 5.2–10.2 times longer than wide, occupies 20–29% of the body length and is 3.3–9.6 times longer than the posterior testis. This new species also differs in having a posterior testis that occupies 2% of the body width, an elongate and slightly sinuous cirrus­sac 2.0–2.6 times longer than wide, an ovary positioned 18–20% of the body length from the posterior end, a uterine chamber 193–312 (227) x 42–45 (43) and vitelline follicles that extend anteriorly past the intestinal bifurcation.

There are in addition, 2–32 base differences (0.5–9.6% sequence divergence) between the ITS2 rDNA sequence of P.sasali and the remaining Phthinomita species reported here. There are two bases different between the sequences from P. sasali (one replicate) from S. doliatus off Palau and P. brooksi (10 replicates) from S. virgatus off Ningaloo Reef.

Figures

FIGURES 44–46. Phthinomita sasali n. sp. from the intertrabecular spaces of ventricle (heart) of Siganus doliatus off Palau. 44. Adult. Dorsal anteriorly, medially twisting laterally at level of “arrow a”, ventral side to the left, whole mount. 45. Male terminal genitalia, lateral view. 46. Female terminal genitalia, lateral view. Scale­bars: 44,46, 250 m; 45, 100 m.