OREASTERIDAE Fisher 1908

Mah, Christopher L., 2023, A new species of Astrosarkus from Western Australia including new Mesophotic occurrences of Indian Ocean Oreasteridae (Valvatida, Asteroidea), Memoirs of Museum Victoria 82, pp. 143-165 : 144

OREASTERIDAE Fisher 1908

Diagnosis. Body variable, ranging from pentagonal, cushionshaped round bodies to more strongly stellate forms. Disk and arms strongly arched, with large coeloms in large specimens (R>~4.0= cm). Abactinal skeleton reticulate papular regions well developed. Marginal plates well developed but variably obscured by heavily granulate dermal layer, well-developed body wall or other covering. Surface covered by large primary spines, tubercles and/or other accessory structures. Adambulacral plates tall, articular surfaces prominent. Ambulacral and adambulacral ossicles stout, closely spaced, forming diamondshaped chamber over ambulacral groove. Actinal papulae absent. Calcareous interbrachial septum present. Coelomic openings large. Upturned, terminal arm tip. Spicules in tube feet. Modified from Marsh and Fromont (2020) and Mah (2003).

Comments. The Oreasteridae are among the most prominent of shallow-water tropical Indo-Pacific and tropical Atlantic Asteroidea, owing in part to their relatively large size (reaching approximate diameter of 30 cm), conspicuous spination and eye-catching coloration (e.g. Pentaceraster species) (Marsh and Fromont, 2020). Many shallow-water species, such as the tropical Atlantic Oreaster reticulatus , are endangered by tourist fisheries and other human-related activities (e.g. Scheibling and Metaxas, 2010). Many oreasterids are known from shallow-water settings, but the lower limits of their depth distributions are not well understood. Several shallow-water species, known best from reef habitats, display bathymetric distribution into mesophotic depths (e.g. Mah, 2017, and species herein).