Goniocidaris australiae

Goniocidaris australiae is a cidaroid sea urchin, a member of the group often called pencil urchins because of their thick, stout primary spines. It was described scientifically in 1928.

It was described by Theodor Mortensen, the Danish echinoderm specialist whose monumental monographs on sea urchins remain standard references in the field. His 1928 description established the species name still used today.

Specimens from Tasmania bear primary spines tipped with distinct disc-like endings. These ornamented spine tips are a characteristic feature that helps distinguish this species within the cidaroid lineage, whose members already have notably thick primary spines.

As its name suggests, the species is recorded from Australian waters, with Tasmanian specimens being especially well documented thanks to their disc-tipped spines. Like other cidaroids, it lives on the seafloor rather than in reefs or rock crevices typical of many regular urchins.