Middle Jurassic radiolarian fauna from Rotti Island, Indonesia

A well-preserved Middle Jurassic radiolarian fauna was discriminated from c alcareous shale of the Wai Lull Formation on Rotti Island, Indonesia. This fauna is characterized by the presence of Tricolocapsa plicarum, Tricolocap sa ? fusiformis, Stichocapsa japonica, S. convexa, Cyrtocapsa mastoidea, Pr otunuma turbo, Trashsuum maxwelli, Eucyrtidiellum sp., Archaeodictyomitra s p. A. and others. These radiolarians represent the T. plicarum Assemblage r eported from Bajocian and early Bathonian (Middle Jurassic) sequences in Ja pan and southeastern Europe. Based on accumulated micropaleontological evid ence in Timer Island contributed by the present authors, Rotti Island was p robably positioned within a warm water current system originating in the lo w latitude Tethyan realm through the Middle Jurassic. Fifteen species belon ging to seven genera are systematically investigated. Among them, Tricoloca psa multispinosa and Tricolocapsa matsuokai are described as new. (C) 1999 Elsevier Science Ltd. All rights reserved.