ABSTRACT
Study of the fauna associated to holothuroids from Hansa Bay (Papua-New-Guinea) allowed to record a new symbiose between the holothuroid Holothuria (Metriatyla) scabra and the crab Hapalonotus reticulatus. Each of the collected individual of holothuroid was infested. There was only one crab per infested holothuroid. Each crab was located in the right respiratory tree near the cloaca. Because of its size H. reticulatus considerably distend the wall of the respiratory tree to form a membranaceous cyst. This association, therefore, appears to be of the nature of parasitism. However, the crab does not feed upon host tissue but seems more to filter their food from water that passed through the respiratory tree of its host.
