发现于滇东特异保存的澄江生物群和关山生物群，为揭示后生动物的起源和早期演化提供了重要的古生物学证据。随着筇竹寺末期滇中古陆的上升隆起，昆明-武定地区沉积了较粗粒的碎屑岩，除遗迹化石外，实体化石少有发现。三年前申请人在昆明小石坝村红井哨组地层底部首次发现保存了软躯体的多门类后生动物化石。经系统采集得到大量此类良好保存化石，其地层层位介于澄江生物群和关山生物群之间，弥补了生物演化历程所缺失的环节，展示了寒武系第2统（筇竹寺阶至沧浪铺阶）滇东海盆海洋生物群落的基本组构、演替和多样性变迁的方方面面。小石坝生物群仍以节肢动物为主体，所展现的形体构造细节，为研究原始节肢动物的躯体构建和演化提供了重要信息。与澄江和关山化石群的埋藏和保存特征相比较，一些小石坝化石独特的"埋藏剖析"模式，可望为探讨寒武纪化石宝库的埋藏机理提供重要线索。

The exquisitely preserved Chengjiang and Guanshan biotas have provided critical insights into the origin, diversification and evolution of early matazoans. With the uplift of the Central Yunnan Archicontinent at the end of the Chiungchussian, a set of clastic rocks have been deposited in the Kunming-Wuding district, where fossils are extremely rare except some ichnofossils. With extensive fieldwork during the last three years we have collected many soft-bodied fossils belonging to various metazoan groups from the lower part of the Cambrian (Series 2) Hongjingshao Formation in the eastern suburbs of Kunming. Because of occurring between the Chengjiang and Guanshan Biotas, these extraordinary fossils (named Xiaoshiba biota) may be the missed link to yield significant data concerning the evolution of these early metazoans. With remarkable variation in morphology and component, they have also clearly shown the replacement of a new biota to an old one with times within the Eastern Yunnan Sea. The Xiaoshiba biota dominated by arthropods provides valuable information for recognizing detailed structures and body plans of some primitive arthropods. In comparison with the Chengjiang and Guanshan biotas, the Xiaoshiba biota has its own unique burial pattern (e.g.,"taphonomic dissection"), which may shed light on the underlying taphonomic mechanism associated with the preservation of these fissil Lagerst?tten.