Color diversity and distribution of sea urchin Tripneustes gratilla in Cenderawasih Bay ecoregion of Papua, Indonesia

Tripneustes gratilla is a sea urchin with a variety of colors, which is associated with adaptability to the environment. The color diversity of sea urchin in the Cenderawasih Bay ecoregion has not been studied yet. Therefore, we investigated the habitat influences on color pattern and distribution of T. gratilla at Cenderawasih Bay. One hundred and seven individuals of T. gratilla were randomly collected in 5 different locations in Cenderawasih Bay. There are 35, 30, 13, 20 and nine individuals from Manokwari, Wasior, Biak, Nabire, and Yapen, respectively. The result showed the test (skeleton), spine, and tube feet color of T. gratilla in Cenderawasih Bay have 31 different colors. Tangency analysis indicated that the color diversity was associated with location site of T. gratilla at Cenderawasih Bay. Black-white is dominant test color of T. gratilla and occurs in all populations, whereas dark purple-orange only occurs in Wasior population. Five spine colors of T. gratilla were not uniformly distributed in all populations. The white color spine is dominant and occurs at all locations while reddish orange occurs only in Wasior. Moreover, the color of tube feet is very influenced by the environment.