华南上泥盆统法门阶哲杜斯贝动物群的埋藏学和居群动力学特征  

Taphonomic features and population dynamics of the Upper Devonian Famennian Dzieduszyckia fauna in South China

作　　者：李彤 董琳[1] 袁志伟 凌坤 甯濛 秦树健 杨润宇 刘威 聂婷 李辰卿 孙元林[1] Li Tong;Dong Lin;Yuan Zhi-Wei;Ling Kun;Ning Meng;Qin Shu-Jian;Yang Run-Yu;Liu Wei;Nie Ting;Li Chen-Qing;Sun Yuan-Lin(School of Earth and Space Science,Peking University,Beijing 100871,China;Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]北京大学地球与空间科学学院,北京100871 [2]成都理工大学沉积地质研究院,四川成都610059

出　　处：《古地理学报》2021年第6期1210-1224,共15页Journal of Palaeogeography：Chinese Edition

基　　金：国家自然科学基金项目(编号:41772015,41672334)资助。

摘　　要：哲杜斯贝是一种以高丰度和低物种分异度为显著特征、在全球广泛独立分布的小嘴贝类。笔者对华南台地相和台间盆地相5个含哲杜斯贝类上泥盆统剖面进行沉积环境和埋藏特征研究,确定华南哲杜斯贝类的原生沉积环境为台地的正常浅水,这与美国和摩洛哥生长在冷泉环境中的哲杜斯贝不同,表明其既可在浅海环境中生长,也可以在冷泉环境中生长,具有较强的生态可塑性。台地相(原地埋藏)的3个哲杜斯贝种群具有以下特征:(1)均呈现出壳体呈层状紧密堆积、集群生长特点,丰度极高,并且有相当数量的个体呈现出由于拥挤生长而导致的壳体生长畸形现象;(2)缺乏其他底栖后生生物,显示了极低的生物多样性;(3)壳体大小—频率分布和生存曲线揭示了3个哲杜斯贝种群都具有非常低的幼年期死亡率特点,同时同一介壳层内哲杜斯贝个体大小均一,表明绝大多数的个体能够达到或接近自然寿命后死亡。上述证据表明,哲杜斯贝具有密集群居生活的习性,其生活在一个独特的、不适合其他后生底栖生物生存的环境。Dzieduszyckia is a rhynchonellide brachiopods genus,featured by its bisulcate,strongly costate shell.It is widely accepted that Dzieduszyckia developed in cold-seep environments.This study aims to investigate the primary living environments of Dzieduszyckia in South China and their population features.Comparison of depositional features between coquinas from platform and intra-platform basin indicates that Dzieduszyckia in South China primarily occupied the platform niches,which is different from that in North American and Morocco.It suggests that Dzieduszyckia had a larger ecological plasticity than the modern organisms present in the cold-seep environment.More than one thousand specimens of Dzieduszyckia from three localities were collected in this study.These three populations have an extremely high abundance with high proportions of growth asymmetry,which resulted from squeezing of individuals during growth,sug-gesting a dense crowed life habit for the brachiopods.The Dzieduszyckia populations barely coexisted with other benthic animals,showing an extremely low diversity in the entire area.Length-frequency distribution and survivorship curve reveal that each of the Dzieduszyckia populations has a low juvenile mortality.The identical shell length in the same natural coquina also supports that the majority of individuals grew up and died naturally.All evidence suggests that Dzieduszyckia takes tight-growth pattern as the survival strategy,living in a unique environment that was not suitable for other benthic organisms.

关 键 词：Dzieduszyckia(哲杜斯贝) 原地埋藏 台地相 台间盆地相 高丰度 低物种分异度 生长畸形 

分 类 号：Q915.5[天文地球—古生物学与地层学]