About Asterodiscides truncatus (Coleman, 1911)
This starfish, Asterodiscides truncatus, has reticulately arranged plates on its aboral (upper) surface, with brightly coloured tubercles scattered between the plates. It has only a few inconspicuous marginal plates, but the superomarginal plate at the end of each arm is very large. Its tube feet are tipped with suckers and do not contain spicules. The tubercles vary in size and colour, forming a red, purple and orange pattern across the aboral surface, and there is a pair of very large tubercles at the tip of each arm. A. truncatus is endemic to Australia. It occurs on the south and east Australian coasts, the western end of the Norfolk Ridge, and the Kermadec Islands. In southern Australia, it is a deep water species that inhabits rocky habitats at 120 m (400 ft). In New South Wales, it is found on shallow rocky reefs in the subtidal zone. This starfish feeds by grazing on sponges and other colourful benthic organisms at the base of kelp forests, where its bright colouring lets it remain inconspicuous. A commensal shrimp sometimes lives among the starfish's tubercles. A. truncatus has been observed releasing gametes into the water column by standing on the tips of its arms to lift its body off the sea floor. Still, little is known about the biology of this starfish.
