扬子地台寒武系第2统布尔吉斯页岩型化石库研究

Soft-bodied fossils, supplied by Cambrian Burgess Shale-type deposits from the Yangzte Plateform over the last three decades, have led to many conspicuous and important discoveries in the development and evolution of early metazoans. Based on numerous exceptionally preserved specimens from the Xiaoshiba section in the eastern suburb of Kunming, together with other Burgess Shale-type fossils recently unearthed from eastern Yunnan and southern Sichuan, as well as Orsten-type material, this project will carry out a series of innovative approaches by focusing on anatomy of soft parts and delicate structures exceptionally preserved, to well recognize the basic body plans of some Cambrian metazoan lineages. In particular this study will examine precisely the head organisation, visual system, mouthparts, specialized appendages, trunk segmentation and ecdysis of some arthropod groups to reveal their developmental modes (including homology evaluation, morphological diversition and stasis) and evolutionary histories. Moreover it is worth examining appendage differentiation and related functional morphology for some well-known lobopodians, and a comprehensive investigation on fine details ofhyolith and brachiopd shells available from phosphatized material may shed light on evaluating the similarity and differentiation of these lophophorates. The Xiaoshiba Lagerstätte, as an intermediate link between the Chengjiang and Burgess Shale faunae, is potentially significant to provide critical information for a better understanding of the divergence and evolution with time of some major metazoan groups mentioned above. In addition, analyses on the taphonomy and geochemistry of the surroundings may clarify the mechanisms and patterns of preservation. In general, based on exquisite fossil Lagerstätten, along with objective evidence documented in previous studies and meticulous examination by means of SRXTM or X-ray micro-CT technology, this project attempts to make new breakthroughs in paleobiology and early life evolution substantially and theoretically.

广泛分布于扬子地台寒武系含软体附肢的布尔吉斯页岩型化石库，历经30余年研究已成就了许多有关后生动物早期演化的重要发现和进展。本项目依据采自昆明小石坝的大量标本，结合新近发现于滇东、川南的同类素材，辅以奥斯坦型化石，开启新的思路和探索途径。研究将注重软躯体、精细构造的剖析，识别早期后生动物类群的躯体构建。侧重若干节肢类群头部组构、视觉系统、口器、特化附肢、体节增生与蜕壳，认知其生长模式（包括性状同源性、形态趋异或保守进化）和各自演变规律。探讨叶足类附肢分异与形态功能。辨析腕足类及软舌螺类躯体各部发育的异同、生理功能和分类学意义。小石坝化石库作为一进化中间环节，确保为上述后生动物随时代变迁的分异与进化提供重要信息。此外分析这些化石的埋藏和地化特性，试探其保存机理与模式。总之，基于已掌握的化石库，借鉴前人成果，运用高科技检测手段，力求在化石生物学和早期生命演化前沿取得新突破，并在理论上有所建树。

基于产自华南寒武系含软体附肢的特异化石库，结合多年此类化石的研究经验和资料积累，本项目深入探讨了布尔吉斯页岩型保存的小石坝生物群、范店生物群和关山生物群化石。寻求新的思路和探索途径，注重细微，识别了一些早期后生动物类群的躯体构建（侧重头部附肢、附肢与体节的组构），个体发育特征并辨析其生长模式和各自演化规律（包括直接或变态发育，眼、附肢、躯体随时间推移呈现的形态趋异或保守进化）；剖析了若干类化石的埋藏和地化特性，试探其保存机理和模式。力求别开生面，做出以下重要（含突破性）贡献：.1）小石坝生物群绿藻化石的新发现，充实了寒武纪该类群因稀缺而留下的空白，为承接其前寒武纪祖先类群和新地层的代表份子起到桥梁的作用。同时为新近报道的寒武纪“潜在干群苔藓虫”的归属提供了可靠旁证。2）首次从细微处揭示了抚仙湖虫类附肢独特的结构及其功能特征，由此更全面地认知这类中国特有的早期干群真节肢动物。3）详尽报道了产自四川乐山沙湾的范店生物群，拓展了澄江生物群的时空分布，为研究随时代变迁澄江生物群的地域分布、各类生物的迁徙演化提供了实证。4）首次报道了行隐居生活的寒武纪曳腮动物，为认知该类动物的生活模式与当时的生态系提供了实例。5）首次发现原位保存于雌性鳃曳蠕虫体内的卵母细胞，并为认知其繁殖方略提供了关键信息，强调了生态对曳腮类繁殖与生活方式的巨大作用。此外，分析推导了抚仙湖虫类Alacaris的蜕壳模式，研究还涉及到寒武纪一些特异和疑难的动物类群，如Sidneyia，非三叶虫节肢类，以及古蠕虫，等等。总之，本项目充分利用“高保真”的特异化石，借鉴和运用现代生物学、沉积学等学科的研究成果，借助大型电子设备的先进功能，为解答若干后生动物类群以及与古环境背景密切相关的问题提供了关键数据，为化石生物学研究和早期生物演化做出了实质性贡献。