南海永暑礁晚全新世微型腹足类——仁螺目,古腹足目,盘足目(英文)

LATE HOLOCENE MICROGASTROPODS FROM THE YONGSHU REEF LAGOON OF THE SOUTH CHINA SEA——Order Cocculiniformia, Vetigastropoda, Discopoda

南海南沙群岛永暑礁南永3井揭示了1 680年以来礁泻湖的沉积变化。沉积柱样主要由沉积遗壳组成,其中腹足类是最主要的类型之一。对该井88个样品分析共发现了159个种类和一些难以归入属种的胎壳,大多数种类为该海区首次记录的类型,有四个种是新发现的种类,即Astraea armata sp .nov .,Munditiella flammea sp .nov .,Serpulorbis spiralis sp .nov .,Cerithiopsis bellatulus sp .nov .,主要的优势种包括Acteocina coarctata , Ac-teocinaexilis , Alvania sp .,Boschitestella eloiseae , Cerithidium fusca , Cerithiopsis ingens , Cerithium( Therici-um) elegantulum, Circumstella biconcave , Clathrofenella reticulata , Diniatys dentifer , Granulina cotamago , Lophocochlias minutissi mus , Merelina wanawana , Omalogyra cf .atomus, Ondina elachisinoides , Orbitestella bermudezi , Orbitestella decorata , Plesiotrochus acutangulus , Retusa ( Ventomnestia) bizonata, Ringicula durodai ,Ringicula columnifera , Ringicula niinoi , Scissurella coronata , Tricoliavariabilis , Turbonilla eupellucida。这些种类个体非常微小,大多数小于2 mm。绝大多数种类为典型的热带海区分子,它们具有广泛的地理分布。本文按Okutani(2000)分类系统进行了分类,主要描述了仁螺目,古腹足目和盘足目共40个种的形态特征、地理分布和生态习性,包括2个新种,绝大多数种类系南沙群岛海区首次记录。

The Yongshu Reef lagoon of the South China Sea developed extremely abundant microgastropods in the late Holocene. Based on analyses of 88 samples in the core Nanyong-3 of Yongshu Reef lagoon recording sediments of the last 1 680 years, 159 microgastropod species, including four new species such as Astraea armata sp. nov. , Munditiella flammea sp. nov. , Serpulorbis spiralis sp. nov. and Cerithiopsis bellatulus sp. nov. , have been described with the exception of some protoconches difficult in being diagnosed systematically. Dominated species in the core are Acteocina coarctata , Acteocina exilis , Alvania sp. , Boschitestella eloiseae , Cerithidiurn f usca , Cerithiopsis ingens , Cerithiurn （Thericium） elegantulum, Circumstella biconcave, Clathro f enella reticulata , Diniatys denti f er , Granulina cotamago , Lophocochlias rninutissirnus , Merelina wanawana , Omalogyra cf. atornus, Ondina elachisinoides , Orbitestella bermudezi , Orbitestella decorata , Plesiotrochus acutangulus , Retusa （Ventomnestia ） bizonata , Ringicula durodai , Ringicula columni f era , Ringicula niinoi , Scissurella coronata , Tricolia variabilis , Turbonilla eupellucida. The mierogastropocls are small in size, generally less than 2 mm, and they are mostly typical tropic forms, having wider geographic distribution. This paper mainly cleseribes 40 species , inelucling two new species, under Order Coeeuliniformia, Vetigastropocla and Diseopocla with their geographic distribution and ecological habits based on systematical classification of Okutani （2000）. The majority of species are the first reeorcls in this area.