华南晚二叠世长兴期浅海相与深海相双壳类对比分析

Comparison of Bivalves from Shallow Sea and Deep Sea during the Changhsingian, Late Permian in South China

摘要: 二叠纪–三叠纪之交生物大灭绝事件促使海洋底栖生态系的主导者由腕足类转变为了双壳类等软体动物，了解大灭绝前双壳类的生态分布有助于加深对双壳类的灭绝过程的认识。本研究统计了华南地区已发表文献中的双壳类化石属种名单，对其生活环境、生活方式和摄食方式进行了统计分析，将生活环境划分为浅海相区(包括滨岸和浅海)和深海相区，共统计了54个属，其中浅海相区40属，深海相区24属，浅海相区明显具有较高的生物多样性；共识别出6种生活方式，包括内栖浅掘穴类、内栖深掘穴类、表栖足丝固着类、半内栖类等，浅海相区生活方式种类齐全，而深海相区的生活方式种类较少。从生态功能群的角度来看，深海相区的功能群数量明显低于浅海相区。因此，晚二叠世长兴期双壳类的生物多样性、生态功能多样性与水深有密切的关系，浅海相区较高。

Abstract: The end-Permian mass extinction event resulted in the dramatic change of the dominant group of marine benthic ecosystem from brachiopods to mollusks (bivalves and gastropods). Understanding the ecological distribution of bivalves prior to the mass extinction would help to deepen the understanding of the extinction pattern of bivalves. This study has collected Late Permian bivalves genera from published literatures on South China, and analyzed their living environments, lifestyles and feeding styles. The living environment has been divided into shallow sea facies (including shore and platform) and deep sea facies. In total, 54 genera are collected, including 40 genera in shallow sea facies, and 24 genera in deep sea facies, which indicates significantly higher biodiversity in shallow sea than deep sea. Six types of lifestyles were identified, including shallow infaunal burrowing, deep infaunal burrowing, epibenthic byssus-attached, and semi-infaunal. The number of lifestyles of bivalves showed a great difference between shallow sea and deep sea, with much lower in deep sea. From the perspective of ecological functional groups, the number of functional groups in deep-sea facies is significantly lower than that in shallow sea facies. Therefore, the biodiversity and ecological functional diversity of bivalves during the Late Permian Changhsingian are closely related to the water depth, and much higher in the shallow sea.