The Extinction and Delayed Recovery of Bivalves during the Permian-Triassic Crisis
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摘要: 为了建立早-中三叠世双壳类的残存-复苏模式及深入探讨双壳类迟缓复苏的原因,对全球范围内该时期双壳类属的 时限分布进行了统计.总体来看,3个亚纲(Pteriomorphia、Palaeotaxodont和Heteroconchia亚纲)和5种生活方式(外栖活动 类、外栖固着类、半内栖类、内栖浅掘穴类和内栖深掘穴类)的双壳类均展示出了一致的规律,属级分异度直到中三叠世Anisian 期才恢复到晚二叠世末生物大灭绝之前的水平.二叠纪残存类型在早-中三叠世双壳类中所占的比例逐步降低,从占过 渡层的77.3%降低到了中三叠世Anisian期的33.7%,指示双壳类的缓慢复苏过程.而在整个早三叠世的漫长复苏期中,双壳 类仅遭受背景灭绝,表明双壳类的迟缓复苏受限于长时期的高压环境,随着海洋环境的逐步好转,才逐渐出现新的类型.Abstract: In order to reconstruct the surviva1 and recovery pattern of bivalves and probe into the reasons in the aftermath of the Permian-Triassic mass extinction, a11 available data of the Late Permian to Middle Triassic bivalve genera a11 around the world have been counted and analyzed. The bivalves be1onging to3 subclasses(Pteriomorphia, Palaeotaxodonta, and Heteroconchia) and5 lifestyles(epifaunalattached, epifauna1 motile, semi-infauna1, sha11ow infauna1, and deep infauna1) show a similar recov- ery pattern. The diversity curves of bivalves display that the recovery of bivalves was delayed to Anisian, when the genus diver- sity incrcascd ncarly to thc similar valuc of thc Changhsingian prior to thc End-Pcrmian mass cxtinction.In addition, Pcrmian survivors including1ong-term survivors, holdover species, and Lazarus taxa dominated the bivalves during the Early Triassic, but not in the Anisian(Middle Triassic). Bivalves only suffered background extinction rates during the Early Triassic, indica- ting the delayed recovery of bivalves resulted from1ong-term hostile environments.
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Key words:
- LatePermian /
- Early Triassic /
- bivalves /
- mass extinction /
- biotic recovery /
- stratigraphy /
- environment effects.
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