摘要
结壳生物和宿主以及它们的相互关系构成了海洋硬底群落的一个特殊的生态系统,能够为地史时期的关键事件提供古生态学证据。中晚泥盆世发生了一系列的生物演化和环境事件,其过程和机制仍有许多不明之处。从四川龙门山地区吉维特期—法门期地层中采集了大量被附生的腕足动物宿主,其中的3 067枚腕足动物标本中,筛选具有附生生物的腕足类宿主618枚,鉴定为7种,归入7属。附生生物为6个类群,包括横板珊瑚、四射珊瑚、多毛类、疑源类、变口目苔藓虫以及无铰纲腕足类。本文对腕足类宿主壳体上不同分区附生生物的多样性及丰度进行统计分析。结果显示,腕足动物宿主的壳体,近喙部与主端的分区附生生物丰度都较低,原因可能是其直立底栖时喙部和主端后部靠近底质,附生生物难以附着。附生生物在宿主背壳与腹壳上丰度大小主要与腕足动物的生活方式有关,除成年后仍直立生活的Cyrtiopsis sp.,Cyrtospirifer sp.外,其他腕足类由于成年期躺卧生活,因此背壳上的附生生物明显多于腹壳。而附生生物在各分区的丰度和生长方向则与附生生物的生活类型直接相关,寄生类型生长过程中表现出明显的方向性,而伴生类型则无明显方向性。此外,腕足类的埋藏特征、与附生生物的关系等对沉积环境也具有一定的指示作用。
Epibionts,their hosts,and their interactions comprise a special ecosystem in the marine hard-substrate communities that could provide important paleoecological implications for critical events in Earth history.A series of biological and environmental events occurred during the Middle and Late Devonian,but their processes and mechanisms remain unclear.A total of 3 067 brachiopod specimens were sampled from the Givetian-Famennian of the Longmenshan region in South China.Then,they were examined and separated into seven species,among which 618 specimens were encrusted by epibionts.The epibionts included 6 fossil groups:tabulate corals,rugose corals,tentaculitoid tubeworms,Allonema,bryozoans,and inarticulate brachiopods,which could be further subdivided into eight groups.This study examined the abundance and diversity of epibionts in each brachiopod sector.The abundance and diversity of epibionts were low in the sectors close to the beak and cardinal extremities;it is likely difficult to attach to the shell when it is close to or buried in soft-substrate.The epibiont abundance between two valves is related to the life orientation of the brachiopod.With the exception of Spiriferoids,the other hosts became attached by their pedicle to the substrate in the adult stage,and they attained an inclined orientation with a dorsal valve facing the substrate or a vertically upright life orientation;thus,the epibionts were significantly more abundant on the dorsal valves.However,the direction of the epibionts and the encruster abundance in each sector was dependent on whether they were parasitism or commensalism.The parasitic epibionts have a growth direction,but the commensal epibionts have no clear growth direction.Therefore,the burial characteristics of brachiopods and the relationship between brachiopods and epibionts can indicate the sedimentary environment.
作者
常晓琳
侯明才
石和
CHANG XiaoLin;HOU MingCai;SHI He(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China;Key Laboratory of Deep-time Geography and Environment Reconstruction and Applications of Ministry of Natural Resources&Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu 610059,China)
出处
《沉积学报》
CAS
CSCD
北大核心
2023年第3期673-683,共11页
Acta Sedimentologica Sinica
基金
国家自然科学基金项目(41902120,42050104)。
关键词
泥盆纪
附生生物
腕足动物
结壳模式
古生态
Devonian
epibionts
brachiopods
encrustation patterns
paleoecology
