K Waiho - Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, Terengganu, Malaysia.
H Fazhan - Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, Terengganu, Malaysia.
H Glenner - Marine Biodiversity Group, Department of Biology, University of Bergen, Bergen, Norway.Center for Macroecology and Evolution, University of Copenhagen, Copenhagen, Denmark.
M Hassan - Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, Terengganu, Malaysia.

Rhizocephalan parasites are parasitic crustaceans infecting other crustacean species. They inflict serious morphological, physiological and behavioral changes upon infection. The most notable feature of infected crabs is the development of an externa (female reproductive organ) on the outer layer of the host‟s abdomen. This study provides the first detailed description of the externa of Sacculina beauforti on the orange mud crab Scylla olivacea. In addition, the hepatosomatic index (HSI) between infected and non-infected individuals was compared. HSI was found to be significantly higher in infected individuals than non-infected individuals. The results of this study contribute towards the taxonomic characterisation of the sacculinid rhizocephalan and the impact of S. beauforti towards the immune response of its host.

Sacculina beauforti. Scylla olivacea, Hepatosomatic