NEW SIGHTS ON LOWER CAMBRIAN (STAGE 4, SERIES 2) GUANSHAN BIOTA,YUNNAN, SOUTH CHINA

The Guanshan biota of Yunnan, South China (Series 2, Stage 4, Cambrian; ca. 515~510 Ma) serves as an evolutionary bridge closely linking the earlier Chengjiang (Series 2, Stage 3, Cambrian) and the later Kaili biota (Series 3, Stage 5, Cambrian; also the coeval Burgess Shale biota), and has significant implications for our understanding the evolutionary details of the Cambrian radiation and its aftermath. Typical Guanshan Biota occurs in Wulongqing Formation of Early Cambrian, which is widely distributed in eastern Yunnan, e.g. Kunming-Wuding and Malong-Yilang area; the typical sections are Gangtoucun and Gaoloufang of Kunming, Sapushan of Wuding, Lihuazhuang of Yilang and Wulongqing of Malong. Now a new section of the Guanshan biota is reported from the Lower Cambrian Wulongqing Formation of Huize, Qujin, South China, approximately 100 km north of the Guanshan fossil sites previously reported. Representatives of various phyla recovered therein include not only previously described sponges, palaeoscolecids, arthropods, brachiopods, echinoderms, and vetulicolians, but also a potential new species of Vetulicola. This new occurrence expands the paleogeographic distribution of the Guanshan biota, further allies the biota to the earlier Chengjiang biota and the later Kaili biota (and also the coeval Burgess Shale community), and provides significant paleontological evidence for understanding the early phylogeny and evolution of animal phyla.