Morphology of Calydiscoides-Nemipteris, Sp-Nov (Monogenea), With a Redescription and Revision of the Genus

Abstract

Calydiscoides nemipteris, sp. nov., was recovered from the gills of Scolopsis temporalis (Nemipteridae), collected near Heron I., Great Barrier Reef, Australia. Close examination of the squamodiscs on the opisthaptors of C. nemipteris, C, indianus, and the type-species, C, australis, revealed the structure of the squadmodiscs to be quite different from that in the genus description. Lamellae form a skeletal framework for the sucker-like squamodisc. The seven posterior band-shaped lamellae overlap each other, with their open ends facing outward forming a cavity within the disc with an opening to the exterior. The anterior three lamellae are in the form of complete concentrically arranged circular bands that telescope anteriorly at an angle into the body. In the original description, there was no mention of the sucker-like morphology, and all the lamellae were described as being complete concentric rings that telescoped into each other. Therefore, the genus is redescribed to reflect the morphology of the worms more accurately. In addition, Lamellodiscus japonicus has squamodiscs more similar to those of Calydiscoides than to Lamellodiscus; hence, it has been combined with Calydiscoides. The shape of the male copulatory apparatus, medial transverse bar and other characters differentiate C. nemipteris from its congeners.