New Ediacaran tubular fossils from southern Shaanxi, China

Abstract

Much palaeontology research on biomineralization has been directed to studying the Cambrian radiation of biomineralizing animals. The evolutionary radiation of biomineralization in the Cambrian Period was preceded by weakly biomineralized animals in the late Ediacaran period around 550–539 Ma. Here we report many new tubular fossils from the upper part of the Ediacaran Dengying Formation in the Lijiagou section, Ningqiang area, southern Shaanxi Province, China, consisting of two new genera and species, namely Shufangtubulus inornatus n. gen. n. sp., and Palaeorhopalon spiniferum n. gen. n. sp. The newly discovered materials expand the list of the Ediacaran tubular fossils. The borings first found on the outer surface of Sinotubulites baimatuoensis are similar to those of Cloudina, which may reveal the earliest predator-prey dynamics. The small and delicate drill holes detected on the inner walls of Sinotubulites baimatuoensis are inferred to be infested traces by parasitism.