南沙群岛永暑礁泻湖南永3井晚全新世微型双壳类

LATE HOLOCENE MICROBIVALVES OF CORE NANYONG-3 IN YONGSHU REEF LAGOON OF THE NANSHA ISLANDS,SOUTH CHINA SEA

南沙群岛永暑礁泻湖南永 3井取岩屑样 88个 ,均产有丰富的微型双壳类。本文描述了该井 16 80年以来的微型双壳类 2 4属 2 6种 ,包括 1新种 Philobrya(N eocardia) xishaensis L an,Cai et Feng sp.nov.。 13个种为南沙群岛海区首次记录。该井微型双壳类以 Condylocuna flemingi Maxwell最为丰富 ,Borniopsis ariakensis Habe,Cadella semitorta(Reeve) ,Wallucina(Wallucina) xishaensis L an为常见种。该动物群以热带、亚热带分子为主 ,亦见有热带 -温带的分子 ,显示了典型的热带岛礁双壳类动物群特征。同时也发现一些澳大利亚和新西兰的分子 ,表明西太平洋经向暖流对于双壳类的跨纬度分布起着重要的作用。本区双壳类以生活于潮间带和潮下带的表生栖息型为主 ,悬食型和食沉积物型几乎各占一半。

Eighty eight samples collected from core Nanyong 3 in Yongshu reef, Nansha Islands, South China Sea contain abundant microbivalves. This paper describes Late Holocene microbivalves 26 species of this core, including one new species Philobrya (Neocardia) xishaensis Lan, Cai et Feng sp. nov. Among them, 13 species are first recorded around Nansha Islands. Microbivalves is dominated by Condylocuna flemingi Maxwell. Common species are Borniopsis ariakensis Habe ,Cadella semitorta (Reeve) ,Wallucina (Wallucina) xishaensis Lan. The fauna, dominated by tropic and subtropic representatives and also containing tropic temperate representatives, belong to characteristic tropic island bivalves. There are also some representatives that can be distributed over Australia and New Zealand, indicating that warm current of West Pacific Ocean plays important role for the longitudinal distribution of bivalves. Ecological habits of bivalves are governed by epibenthos living in tide zone and subtide zone. Suspension feeder and deposit feeder almost take a half of the fauna respectively.