Oldhamia radiata: the trace of an undermat miner from the Cambrian Series 2 Xinji Formation, western Henan, North China

Abstract

Oldhamia trace fossils represent a complex horizontal burrow system usually associated with microbial mats, occurring in the upper part of the Cambrian Stage 2 of the Terreneuvian Series, with a peak in abundance during Stage 3 and 4 of Series 2, and then rapidly disappearing in the Wuliuan Stage of the Miaolingian Series. We here report Oldhamia radiata from the Cambrian Series 2 Xinji Formation in western Henan of North China, associated with microbial mats, as evidenced by the presence of wrinkle structures. The distinctive patterns indicate the exploitation of microbial mats by the tracemakers of O. radiata, featuring a specific feeding strategy under the mats where possibly anoxic and sulfidic conditions prevailed during the early Cambrian.