Type host: Siganus argenteus (Quoy & Gaimard), Forktail Rabbitfish (Perciformes: Siganidae).

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

Type locality: Ningaloo Reef (21°54.6’S 113°58.4’E), Western Australia.

Material examined: ex S. argenteus, Ningaloo Reef (WA), Aug. 2003, twenty­two specimens (Holotype no. QM G 225538; Paratype nos. QM G 225539–225547).

Collector: M.J. Nolan.

Etymology

Specific name for our friend and colleague Dr Robert D. Adlard for his efforts during our collecting trip to Ningaloo Reef and for his continued enthusiasm in reading our manuscripts.

Description

Based on 22 whole mounts. With features of genus. Body slightly notched at male genital pore. Intestine; posterior caeca convoluted, sinuous. Anterior testis originating posterior to intercaecal field, but, antero­sinistral to distal termination of right posterior caecum, margins lobed. Posterior testis tear­shaped, margins lobed anteriorly. Cirrus­sac tear­shaped. Internal seminal vesicle spherical, occupying most of cirrus­sac; ejaculatory duct straight; prostatic cells not seen. Ovary obovate, slightly overlapping 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 cirrus­sac, passing posteriorly sinuously, dextral to vas deferens, entering oötype posterodextrally. Oötype ovoid. Mehlis’ gland extending anteriorly to posterior margin of cirrussac, extending posteriorly to mid­section of posterior testis. Uterus extending from oötype, slightly sinuous, sinistral to oviduct. Uterine chamber forming lateral to posterior margin of ovary, sinuous, curving dorsally posteriorly to female pore. Vitelline follicles extending anteriorly to just posterior of vestigial oral sucker, extending posteriorly to level female genital pore, sinistral and dextral to oesophagus, filling intercaecal field, dextral to anterior testis.

Remarks

Phthinomita adlardi differs from P. symplocos in the combination of average body length, the position of the anterior testis, the length:width ratio and the relative size of the anterior testis, the length ratio of the anterior and posterior testes, the form of the posterior caeca and the position of the uterine chamber with respect to the ovary. Phthinomita symplocos has an average body length of 4217, an anterior testis that originates posterior to the posterior caeca, is 5.0–9.2 times longer than wide, occupies 17–30% of the body length and is 3.5–8.1 times longer than the posterior testis. This species also has sinuous non­convoluted posterior caeca and a uterine chamber that originates posterior to the posterior margin of the ovary. In contrast, P. adlardi has an average body length of 5394, an anterior testis that originates posterior to the intercaecal field but antero­sinistrally to the distal termination of the right posterior caecum, is 12.0–21.7 times longer than wide, occupies 38–59% of the body length and is 12.6–38.2 times longer than the posterior testis. Phthinomita adlardi also has sinuous convoluted posterior caeca and a uterine chamber that originates laterally to the posterior margin of the ovary.

There are in addition, 2–27 base differences (0.5–7.9% sequence divergence) between the ITS2 rDNA sequence of P. adlardi and the remaining Phthinomita species sequenced here. Between the sequences from P. adlardi (eight replicates) from S. argenteus from Ningaloo Reef and P. robertsthomsoni from S. argenteus from Lizard Island there are two bases different.