Diadema palmeri is a sea urchin of the family Diadematidae. It was first discovered by William (Bill) Palmer, at a depth of about 40 m (130 ft) off the Poor Knights Islands (3528S 17444E), a small group off the temperate north eastern coast of New Zealand. The species has also been found in other sub-tropical regions around the South Pacific at greater depths, including New Zealand''s Kermadec Islands, and Australia''s lower east coast - off Danger Point to Montague Island, New South Wales (at about 200 m), Lord Howe Island and the Norfolk Island Ridge.