Holocene and Recent shallow soft-bottom mollusks from the Western Gulf of Thailand: Pak Phanang Bay and additions to Phetchaburi fauna

Gastropods and bivalves recently recovered from offshore soft bottoms in the Northern Gulf of Thailand, along with those obtained from the Ban Laem Phak Bia sand spit (Phetchaburi Province) and the Pak Phanang Bay (Nakhon Si Thammarat Province) are described and discussed. Mollusk assemblages in the Gulf appear to be similar to those described in previous papers by the present authors, while the Pak Phanang ones reflect a confined environment which is undergoing heavy modifications. Galeommatoidea, Tellinoidea, Triphoroidea, Conoidea and Pyramidelloidea are the most diverse groups. This paper covers 150 species, of which 3 are proposed as new; 53 remain unidentified and might be, at least partly, undescribed by previous workers. The species treated are complemented with taxonomic remarks when necessary and with information on respective ecological requirements if available. All species are illustrated. A list of references to the mollusk fauna of the Indo-Pacific Region is also given.