Habitat Segregations and Adaptive Morphology of Ostracodes in Intertidal Zones in Indonesia

Abstract

The intertidal Ostracoda fauna from Indonesia, all composed of alive specimens on seaweeds, were studied. Seaweeds, composed of about 15 species, were taken from Madura and Bali Islands. The most dominant taxa in the fauna were family Paradoxotomatidae (genera- Paradoxostoma s.l Brunneostoma and Bradystoma) and genus Xestoleberis. The preference of the species to their habitats were clearly recognized e. g. Brunneostoma sp. 1 andParadoxostoma s. s. were dominant on short filamentous algae, Chania and Botrychium respectively while Brunneostoma sp. 2 and Bradystoma sp. were dominant on tall and smooth-surface algae such as Priorities and Masto hora, respectively. This study also gives a good example of morphological adaptation to the habitats by Paradostomatidae. Species living on tall and smooth-surface algae in the wavy rocky shores have specialized large mouthpart which is used as a sucker to stick to the surface of the algae, and this is a reason why Paradoxotomatidae is the only ostracode taxon able to live on such slippery seaweeds. The result indicates that ostracodes will be a good material for the reconstruction of precise intertidal paleoenvironments.