ASPIDELLA IN REPOSE: TAPHONOMY OF A FRONDOSE EDIACARAN FOSSIL PRESERVED IN CARBONATE ROCKS

Frondose Ediacara fossils typically consist of a discoidal holdfast (referred to as Aspidella when preserved alone), a stalk, and two or more petaloids. They are common and widespread in siliciclastic successions of late Ediacaran age (580–541 Ma), but they are rare in late Ediacaran carbonate successions. This contrast could reflect ecological or taphonomic differences. Resolving these differences is important to improve the paleobiological interpretation of frondose Ediacaran fossils. Here, we report a stalked Aspidella specimen from the Ediacaran Dengying Formation (551–541 Ma) of South China. This and other stalked Aspidella fossils suggest that the holdfast, stalk, and petaloids of frondose Ediacara fossils have decreasing preservation potential, possibly explaining the taphonomic bias against petaloid preservation in many Ediacaran assemblages. Considering this preservational bias, it is likely that frondose Ediacara fossils have a much wider geographic and environmental distribution than currently appreciated, an inference suggesting unusual environmental tolerance of this group of Ediacara organisms.