Kimberley marine biota. Historical data: molluscs

WA Museum Records and Supplements | Updated 7 years ago

ABSTRACT – This paper is part of a series compiling data on the biodiversity of the shallow water (< 30 m) marine and estuarine flora and fauna of the Kimberley region of coastal northern Western Australia and adjacent offshore regions out to the edge of the Australian continental shelf (termed the ‘Kimberley Project Area’ throughout this series – see Sampey et al. 2014). This series of papers, which synthesise species level data accumulated by Australian museums to December 2008, serves as a baseline for future biodiversity surveys and to assist with future management decisions. This present paper deals with the molluscs of the classes Polyplacophora, Gastropoda, Bivalvia, Scaphopoda and Cephalopoda. The molluscs, the most numerically diverse of all of the groups analysed in the Project Area, comprise a total of 1,784 species. Given that (a) the present collation is tightly constrained in terms of locations sampled, depth ranges, dates and institutional databases, (b) there are many undersampled groups (perhaps the majority of families), and (c) the rate of species discovery for molluscs within the Project Area is rising at a rate of approximately 18% per year (according to two independent analyses outlined herein), it is predicted that the eventual total for the Project Area will exceed 5000 species. The molluscan fauna of the Project Area is almost entirely tropical in composition with almost no attenuation of numerical diversity southward, either inshore or offshore. Neither does any pronounced difference exist in numerical diversity across the shelf, despite only 25.32% of species being common to both inshore and offshore locales; the low percentage probably being due to inadequate sampling. A total of 183 species (10.28%) is endemic to Australian waters, with the majority of these endemics (9.32%) occurring only at inshore localities.