A new fossil species of Clypeaster (Echinoidea) from Malaysian Borneo and an overview of the Central Indo-Pacific echinoid fossil record

Abstract

A complete, but fractured and crushed, echinoid corona from early to middle Miocene of Sarawak, Malaysia, is described as a new species, Clypeaster sarawakensis nov. sp. Although similar to modern C. rarispinus, the new species shows a distinct set of characters including petal length, periproct position and gut coiling. The discovery of a new Clypeaster, a genus characterised by a high preservation potential, illustrates that little is known about echinoid evolution and diversification in the Central Indo-Pacific, which features as a biodiversity hotspot since the Oligocene. Besides describing Clypeaster sarawakensis, we also compiled the known Central Indo-Pacific echinoid fossil record and used it to examine the Cenozoic diversity of echinoids. The overall diversity throughout the Cenozoic, and especially the rapid diversity increase at the Oligocene–Miocene boundary, corresponds to diversity trends observed in other taxa from the region.