[关键词]
[摘要]
豫西寒武系第三统张夏组上部保存有大量发育厚壁的遗迹化石。通过野外多剖面多角度观察,结合室内遗迹化石特征统计、宏观—微观结构的分析,发现该遗迹化石的纵切面形态多为I/J形和宽扁 U 形,且多呈簇状或束状的集群分布,具有厚的衬壁,被深色晕圈所围绕。单个潜穴结构由分界清晰的三部分组成:深灰色亮晶方解石组成的填充物、浅灰白色灰泥质衬壁、深灰色微晶方解石和白云石组成的晕圈。根据这些特征将其定名为Schaubcylindrichnus heberti,并对其进行形态功能分析,认为 S.heberti体现了造迹生物复杂的行为习性:两种摄食方式(建造潜穴时的食沉积物以及居住时的漏斗进食),主动避免环境中的不利因素(建造厚的衬壁),以及快速生长的生存策略(不断废弃旧管、建造新管)。在寒武系张夏组灰岩中发育大量且属种单一的 Schaubcylindrich-nus,说明寒武纪生物的行为习性已有显著进化,生物应对复杂环境的能力有了很大提升。
[Key word]
[Abstract]
Trace fossils with thickly lined tubes are abundantly preserved in the Zhangxia Formation of the Cambrian Series 3in western Henan Province.The morphological features are described here by observation from several field sections and microscopic photos;they are I/J-shaped or flat U- shaped tubes in the vertical cross-section,which are thickly lined,and a bundle of tubes are usually packed by an irregular aureola.A single tube is made of three distinct parts:sparry calcite fillings, packstone linings,and microcrystalline calcite and dolomite aureola.Based on these morphological features,we propose that this trace fossil should be re-assigned to Schaubcylindrichnus heberti.According to the functional morphologic analysis, we hypothesize that the trace maker was capable of complex behaviors and survival strategies as follows:various feeding modes-deposit feeding during building burrow and filter feeding after completed construction;actively avoid adverse factors by constructing thick lining;and rapid growth strategy-building new tubes and abandoned the little ones unceasingly forming a bundle of tubes.Intensive bioturbation by the single ichnos-pecies of Schaubcylindrichnus found in Cambrian limestones shows that significantly improvement of biological behavior evolution and adaptation for hostile habitat.
[中图分类号]
[基金项目]
国家自然科学基金(41502106,41472083,41102008,U1204404);油气资源与勘探国家重点实验室开放项目(PRP/open-1407);河南理工大学博士基金项目(B2014-072)资助