In February 1983, fragments of approximately 50 ml volume were cut in situ from the dorsal surface region (<2 cm) of a single specimen of Rhopaloeides odorabile at Davies Reef and were attached while still underwater to PVC plastic plaques (100×100×2 mm) with nylon cable ties. The newly transplanted sponge fragments were placed in groups of four at three depths (5, 10 and 20 m) under illuminated and shaded conditions. Body size was assessed by displacement volume after one month and at quarterly intervals thereafter. After 401 days the whole transplants (<2 cm in thickness) were analysed for terpene content. Whole specimens of the sponge Rhopaloeides odorabile were also collected from fully illuminated and partially shaded forereef sites at a depth of 10 m from an inshore reef (Pandora Reef), two midshelf reefs (Rib Reef and Davies Reef) and an outershelf reef (Myrmidon Reef) in the central Great Barrier Reef. Specimens for chemical analyses were frozen whole and later subsampled. Two large specimens, each collected in June 1984 from fully illuminated sites at Myrmidon Reef, were selected for their relatively high total diterpene content and subsampled with replicated cores to depths of 9 cm through the dorsal ridge (including areas with and without oscules) and lateral body regions for specimen 1 and only through portions of the dorsal ridge without oscules for specimen 2. Cores were 0.2 and 1.0 cm in width for specimens 1 and 2, respectively, and were cut into 1 cm lengths for analysis. Since diterpene content was found to be highest in surface tissues, further consideration of large specimens was restricted to the dorsal surface tissues (0-1 cm). Duplicate surface tissue samples (3×6 cm) were taken from large specimens collected during October 1984 from fully illuminated sites on Pandora and Rib Reefs and from partially shaded sites on Rib Reef (n = 4-6 per collection). Chemical data were reported as percent dry weight of sponge tissue (w/w).
This research was undertaken to determine whether a group of Great Barrier Reef sponges, attributed to the genus Spongia, which were observed to have unusual skeletal organisation and terpene composition, should be placed into a new genus.To confirm this, it was necessary to determine whether observed variation in terpene composition and external characters such as pigmentation and shape could be related to habitat differences such as depth, available light and location across the continental shelf.
A full description of the new species is given in the published paper.Type species: Rhopaloeides odorabile n. sp.Type data: Great Barrier Reef, Australia. Davies Reef. 10 m. Holotype Australian Museum Z4965.
