Abstract

Shaanxilithes ningqiangensis is an enigmatic ribbon-shaped fossil from the upper Ediacaran Gaojiashan Member of the Dengying Formation, southern Shaanxi Province, South China. This taxon has also been reported from Ediacaran successions in North China and possibly in Siberia, making it a potential index fossil for interregional biostratigraphic correlation of upper Ediacaran successions. At Gaojiashan, Shaanxilithes ningqiangensis is often preserved along bedding planes of phosphate-rich silty and calcareous shale, with no evidence of vertical intrusion into adjacent beds and containing little to no carbonaceous material. Here, through detailed microstructural and microchemical investigation using a combination of analytical techniques, taphonomic details of Shaanxilithes ningqiangensis and potentially related forms are revealed, showing that these enigmatic fossils are preserved as clay molds. Together with other taphonomic features, such as abruptly bent ribbons, overlapping but not crosscutting ribbons, and co-occurring discoidal structures interpreted as disarticulated sections of the original organism, the new data suggest that Shaanxilithes ningqiangensis is a body fossil consisting of serially arranged units that are discoidal, lensoidal, or crescentic in shape. Shaanxilithes ningqiangensis is not a trace fossil as some previous researchers have suggested.

You do not currently have access to this article.