Ankistromeces olsoni, 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 : 30-32

Ankistromeces olsoni n. sp. ( Figs. 12–14 )

Type host: Siganus fuscescens (Houttuyn) , Black Spinefoot ( Perciformes : Siganidae ).

Site in host: Atrium (heart).

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

Material examined: ex S. fuscescens, Heron Island (QLD), Feb. 2002, May 2003, eight partial and complete specimens (Holotype no. QM G 225525 ; Paratype nos. QM G 225526–225527 ) .

Collector: M.J. Nolan.

Etymology

Specific name for Dr Pete Olson from the Natural History Museum, London, for his contributions to the field of parasite phylogenetics.

Description

Based on eight partial and complete mounts. With features of genus. Body not distinctly notched at male genital pore. Testis originating posterior to intercaecal field, margins irregular. Cirrus­sac dorsally directed. Internal seminal vesicle ovoid, occupying ventral region of cirrus­sac; ejaculatory duct sinuous, antero­dorsally directed; prostatic cells not seen. Ovary ovoid, dextrally orientated, posterior to posterior margin of testis. Oviduct not seen. Vitelline duct forming in space between posterior margin of ovary and anterior margin of cirrus­sac, passing posteriorly sinuously, ventral to vas deferens and cirrus­sac, forming vitelline reservoir posterior to posterior margin cirrus­sac, entering oötype posteriorly. Oötype ovoid, antero­ventrally directed. Mehlis’ gland extending anteriorly to posterior margin of cirrus­sac, extending posteriorly to anterior margin of excretory vesicle. Uterus extends anteriorly from oötype, ventral to vas deferens and cirrus­sac, sinistral to vitelline duct and vitelline follicles, level with posterior margin of ovary passes dorsally across mid­line, sinistral to posterior margin of ovary, dorsally loops posteriorly to form uterine chamber. Uterine chamber convoluted anteriorly, sinuous posteriorly, extends from posterior margin of ovary to anterior margin of cirrus­sac. Vitelline follicles compacted; originate in anterior half of body, extend anteriorly past intestinal bifurcation, extend posteriorly past posterior margin of ovary, fill intercaecal field, sinistral to testis anteriorly, dextral to ventral margin of testis, ovary and uterus posteriorly, ventral to vas deferens, proximal uterus and uterine chamber.

m; 13, 100 m.

Remarks

Ankistromeces olsoni n. sp. differs from A. mariae and A. dunwichensis in having the combination of a body 1379–2922 (2193) x 51–90 (78), an oesophagus that occupies 19–26% of the body length, posterior caeca 27–34% of the body length and 20.5–25.7 times longer than the anterior pair, an anterior testis 3.3–8.7 times longer than wide and that occupies 12–22% of the body length, the cirrus­sac and ovary positioned 10–14% and 13–21% of the body length from the posterior end (respectively) and a uterine chamber 134–211 (185) x 26–41 (32). Ankistromeces olsoni differs from A. dunwichensis in addition to the above mentioned features in having an ovoid ovary rather than a tearshaped lobed ovary and vitelline follicles that originate in the anterior half of the body rather than in the posterior half.

There are in addition, 1–22 base differences (0.3–6.4% sequence divergence) between the ITS2 rDNA sequence of A. olsoni and the remaining Ankistromeces species sequenced here. From Ankistromeces sp. Z from Ningaloo Reef (five replicates), A. olsoni from Heron Island (four replicates) differed by one base.

Figures

FIGURES 12–14. Ankistromeces olsoni n. sp. from atrium (heart) of Siganus fuscescens off Heron Island. 12. Adult. Lateral view. whole mount. 13. Male terminal genitalia, dorsal view. 14. Female terminal genitalia, lateral view. Oviduct not observed in single specimen. Scale­bars: 12,14, 250