Asterodiscides truncatus

Lore & Background

The firebrick starfish has plates on its aboral (upper) surface arranged in a reticulate fashion, with brightly coloured tubercles scattered between them. There are only a few inconspicuous marginal plates, but the superomarginal plate at the end of each arm is very large. The tube feet are tipped with suckers and lack spicules. The tubercles vary in size and colour, creating a red, purple, and orange pattern on the aboral surface, with a pair of very large tubercles at the tip of each arm.

Endemic to Australia, A. truncatus occurs on the south and east coasts, on the western end of the Norfolk Ridge, and the Kermadec Islands. In southern Australia it is a deep water species found in rocky habitats at 120 m (400 ft), but in New South Wales it occurs on shallow rocky reefs in the subtidal zone.

It feeds by grazing on sponges and other colourful benthic organisms at the base of the kelp forest, where its bright colours are inconspicuous. A commensal shrimp can sometimes be found living among the tubercles. It has been observed releasing gametes into the water column by standing on the tips of its arms to raise its body off the sea floor. However, little is known of the biology of this starfish.

Reader's Guide

The firebrick starfish is significant as a visually striking member of the family Asterodiscididae, with its bright red, purple, and orange tubercles making it notable among shallow and deep-water starfish. Its distribution across eastern and southern Australia, the Norfolk Ridge, and the Kermadec Islands highlights its presence in both temperate and subtropical marine environments. The species demonstrates an unusual depth range, occurring in deep rocky habitats at 120 meters in southern Australia while also inhabiting shallow subtidal rocky reefs in New South Wales. Ecologically, it plays a role as a grazer on sponges and other colourful benthic organisms at the base of kelp forests, where its own bright colours serve as camouflage. The observation of it releasing gametes while standing on its arm tips suggests a unique spawning behavior, though much of its biology remains unknown. The presence of a commensal shrimp living among its tubercles indicates a symbiotic relationship that adds to its ecological interest. Its legacy lies in being a colorful but poorly understood species that exemplifies the diversity of Australian and New Zealand marine life.