Crustaceana 86 (6) 718-727 HYASTENUS BARU, A NEW SPECIES OF SPIDER CRAB FROM INDONESIA (BRACHYURA, MAJOIDEA, EPIALTIDAE) WITH A KEY TO THE SPECIES OF HYASTENUS BY AMANDA M. WINDSOR 1 ) and SHANE T. AHYONG Australian Museum, 6 College Street, Sydney, NSW 2010, Australia ABSTRACT A new species of spider crab, Hyastenus baru n. sp., was collected from deep water off the eastern Indonesian island Kei-Besar by the French-Indonesian KARUBAR expedition in 1991. The new species is similar to several other members of the genus, but differs in spination of the carapace and ambulatory pereopods. RÉSUMÉ Une nouvelle espèce de crabe araignée, Hyastenus baru n. sp., a été collectée en eau profonde au large de l’île est-indonésienne de Kei Besar, par l’expédition franco-indonésienne KARUBAR en 1991. Cette nouvelle espèce ressemble à plusieurs autres espèces du genre, mais en diffère par la répartition et le nombre d’épines de la carapace et par les péréiopodes ambulatoires. INTRODUCTION The epialtid spider crab genus Hyastenus White, 1847 currently includes 38 valid species (Ng et al., 2008) that were divided into three groups, named Groups 1-3 based on gonopod 1 morphology by Griffin & Tranter (1986). Most species of Hyastenus belong to Group 1, recognised by the relatively straight gonopod 1 with a subterminal aperture and convex lobe behind the apex. An undescribed Hyastenus Group 1 species was collected from the Banda Sea near the Kei Islands, Maluku Province, Indonesia as part of the KARUBAR expedition to Indonesia in 1991. This species, known from a single male specimen, is sufficiently distinct from other species of Hyastenus to warrant its recognition as a new species, described below. 1 ) Corresponding author; e-mail: amwindsor@gmail.com © Koninklijke Brill NV, Leiden, 2013 DOI:10.1163/15685403-00003202