pedicellariae - tridentate and triphyllous - are rare or restricted only to certain areas of the test. The relatively blunt spines are quite short and are usually hidden below the flower-like pedicellariae. They can vary from white, pink, yellow, light green, to purple in coloration with lighter-colored tips. Other members of the genus Toxopneustes are similar in appearance and can be mistaken for flower urchins. Toxopneustes roseus can be distinguished by the uniform coloration of their tests of pink, brown, or purple. It is also restricted to the East Pacific and thus aren't found together with flower urchins. Toxopneustes elegans, which is only found around Japan, can be distinguished by the presence of a distinctive dark stripe just below the tips of their spines. Toxopneustes maculatus is a very rare species known only from specimens from Réunion, Christmas Island, and the Palmyra Atoll. It can be distinguished by the bright violet coloration on the bottom and in a band around the middle of their tests. Distribution and habitat Flower urchins are widespread and common in the tropical Indo-West Pacific. They can be found north from Okinawa, Japan, to Tasmania, Australia in the south; and west from the Red Sea and the East African coast, to Raratonga in the Cook Islands in the east. In Mexican waters, the Flower Urchin can be found in every waters of the Pacific with the exception that they are absent from Guerrero Negro (Bahia Tortugas), Baja California, northward along the central and northwest coasts of Baja. They are found among coral reefs, coral rubble, rocks, sand, and seagrass beds at depths of from the water's surface. They may sometimes partially bury themselves on the substrate. Ecology and behavior Diet Flower urchins feed on algae, bryozoans, and organic detritus. Predators Flower urchins have few predators. They are known to be toxic to fish. One of the few organisms capable of consuming flower urchins with no apparent adverse effects is the predatory corallimorph Paracorynactis hoplites. However it is unknown if flower urchins are among its natural prey. Associated species The commensal alpheid shrimp Athanas areteformis, can sometimes be found living among the spines of flower urchins (as well as burrowing urchins and collector urchins). The intestines of flower urchins can also serve as habitats for the commensal flatworm Syndesmis longicanalis. Flower urchins are also common hosts of the zebra crab, Zebrida adamsii. These tiny crabs are obligate