INSIGHTS INTO VENDOTAENID TAPHONOMY AND STRUCTURE: NEW DATA ON AN OLD FOSSIL

One of the most well-known Precambrian carbonaceous fossils is the fibrous, enigmatic Vendotaenia. These fossils are typically found in shales (or other fine gained aluminosilicate rocks), are relatively easy to identify, and can often be found in great abundance on bedding planes. This is the case in the rocks of the late Ediacaran Dengying Formation (551–541 Ma) from the Three Gorges region of South China. Most Vendotaenia specimens are found within the Shibantan Member (the middle member of the Dengying Fm.) which is composed of dark gray, thin-bedded, bituminous limestone interpreted to have been deposited in a subtidal environment. The lithology of the Shibantan Mbr is unique in that the thicker carbonate units (cm-scale thickness) are separated by very thin (mm-scale thickness) clayey layers, many of which are thought to be the remnants of microbial mats; these clayey layers are where most Vendotaenia specimens are found. However, the shear amount of carbonate matrix, even in the clay-rich layers, makes extracting carbonaceous fossil material a challenge. Here we report a novel method to extract large carbonaceous Vendotaenia ribbons from carbonate rocks, which may hold promise for a more complete understanding of the taphonomy and taxonomic identity of Vendotaenia. From our preliminary taphonomic analyses, Vendotaenia appears to be preserved comparably to other carbonaceous compressions, with clear indications of clay templating and remnant organic material.