On the upper surface paxillae (Latin, "little stakes"), little pillars with flattened summits, are cream, grey or brown, the colours sometimes making a chevron pattern.

Archaster has spines that are flat and blunt and on its upper surface has parallel, radial rows of plates while Astropecten polyacanthus does not.

[6] In a case of paralytic poisoning in Japan it was found that the victim had eaten a trumpet shell, Charonia lampas, which had acquired the toxin through its food chain, thus implicating Astropecten polyacanthus.

In a study that followed this incident, most of the 54 comb stars assayed contained TTX, with one individual having a toxicity score of 520 mouse units per gram.

[6] The comb star is sometimes kept in reef aquaria where it is efficient at clearing detritus and uneaten food from the sand or gravel.