Orsten型特异保存化石研究概述

STUDIES ON ORSTEN-TYPE FOSSIL LAGERSTTTE

Orsten型化石是一类主要产自寒武系及奥陶系个体微小却珍贵的特异保存化石。虽仅有较短的研究历史,其精美的保存所携带的重要信息,已开拓出一些新的研究方向和领域,倍受当前相关学者的关注。以往事实表明中国南方是世界Orsten型化石最重要的产出地之一,期待着研究的深入。利用此类化石细致入微的保存,结合新的思路,可识别早期动物胚胎的基本形态、发育特征和寒武纪若干后生动物类群的基本体态特征;注重节肢动物类群早期幼年个体,辨析其生长模式(包括躯体分节,直接或变态发育,随时间推移可能呈现的形态趋异或保守进化),以及它们分属类群的演化规律;探讨至今知之甚微此类特异埋藏的机理。总之,"以小见大",解答传统古生物学研究力所不及,与早期后生动物演化密切相关的若干问题。

＂Orsten＂-type fossils are typically tiny embryos and cuticle-bearing animals,which were predominantly found from the Cambrian and Ordovician at a few sites distributed worldwide.With extraordinary preservation that may offer critical clues or evidence for exploring new research areas,this kind of fossil-Lagersttte has attracted profound attention shortly since its first discovery in the 1970＇s.As one of the most important regions in the world,southern China is well known and still of great potential for yielding many Orsten-type fossils.On the basis of such material displaying the highest fidelity of detail together with some current innovative ideas,it is expected to verify the essential body plan of some initial animals,and the basal morphology and development of their embryos.As focused on their early instars,investigations on Orsten-type arthropods may shed light on their developmental mode（including the trunk segmentation,direct or indirect development,the diversification or conservative evolution with time）,as well as the evolutionary trend of the clades these arthropods belong to.Furthermore,the underlying taphonomic mechanisms associated with this exceptional preservation,although poorly understood,is worthy of evaluating.In general,these tiny fossils may resolve some significant problems related to the early evolution of metazoans.