NONDESCRIPT BUT STILL IMPORTANT! REPORTING TWO NEW TUBULAR FORMS AND THEIR TAPHONOMY FROM THE TERMINAL EDIACARAN WOOD CANYON FORMATION, NV, USA

Recent reports have highlighted the distribution and taxonomy of several tubiform and cloudinomorphic fossils from terminal Ediacaran (ca. 550–540 Ma) strata of the Great Basin region, Nevada, USA. While outwardly comparable in preservation to contemporaneous fossils from the Gaojiashan Lagerstätte in China, the taphonomy of the Wood Canyon and Deep Spring assemblages has not been examined in detail. Many of these fossils appear to be preserved as rusty compressions on bedding planes of tan-colored siltstones, green-hued silty shale, and dark grey shale. Like their counterparts in the Gaojiashan, numerous three-dimensionally preserved tubiform fossils have also been recovered. Reported from within rare three-dimensional examples from the Wood Canyon Formation are features interpreted as nephrozoan-like guts, among the oldest-known occurrences of internal organ preservation. During our investigation of the taphonomy of the tubular fossils from the Wood Canyon Formation, we recognized two additional common morphological forms. While these tubes are structurally simple as compared to others from the same unit, we have not found comparable forms that have been formally taxonomically described. Here, we will provide a brief description of these two new simple tubular forms—one that possesses a smooth, originally organic-walled tube with rare instances of an apical bulbous structure interpreted as a holdfast, and the other a wrinkled, slightly conical form with a higher level of sinuosity than the straight form. The preservation of these abundant forms presented important details that helped to inform the taphonomic progression described in our model.