Stuck in the mud: experimental taphonomy and computed tomography demonstrate the critical role of sediment in three-dimensional carcass stabilization during early fossil diagenesis - TIFF stack data

Exceptionally preserved fossils provide critical information on the morphology and ecology of extinct organisms, but their formation remains poorly understood. Experimental taphonomy has produced critical insights that allow us to better understand preservation biases, but they typically do not reflect realistic depositional environments, employ destructive sampling, and are restricted to a two-dimensional setting. Here, we utilize micro-computed tomography to non-invasively visualize the process of decay of carcasses of the branchiopod Triops longicaudatus for a year of post-burial decay. The earliest stages of post-burial diagenesis are dynamic and produce marked differences in relative density within each of the experimental replicates affecting both the carcass and the surrounding sediment. After 64 weeks, specimens are still detectable as three-dimensional voids that capture the body in life position and external morphological features. Sediment plays a critical role in carcass stabilization and the resulting voids provide sites for mineral precipitation needed for exceptional three-dimensional fossilization.

Methods
Dryad Archive of Tiff Stacks

The week 2 scans were completed at the Digital Imaging Facility (DIF) at the Museum of Comparative Zoology, Harvard University, with a Bruker SkyScan 1173 micro-CT scanner. Scans were performed as 180° scans with Al 1 mm filter, 100 kV, 100 µA current, 32 µm voxel size, 12mm stage positioning with 0.4 angle step size and frame averaging of 3. Due to an update on the DIF facilities taking place during the duration of the experiment, week 20, week 42, and week 64 scans were produced on a new Bruker Skycan 1273 using 180° scans with Cu .5 mm filter, 120 kV, 125 µA current, 25.3 µm voxel size, 0.4 angle step size and frame averaging of 3. All scans were reconstructed as TIFF stacks in NRecon (Bruker Corporation). These reconstructed TIFF stacks are archived here.

File types:

The compressed ZIP files were compressed using Windows and will be unzipped to folders of .tif image files.

Folders of reconstructed .tif stacks may be visualized in many programs. Authors used Dragonfly 2019 4.0 (Object Research Systems, Montreal, Canada), please see the associated Dryad repository for this archive. Other visualization tools can import the images here including the free software Drishti, cited below.

Ajay Limaye; Drishti: a volume exploration and presentation tool. Proc. SPIE 8506, Developments in X-Ray Tomography VIII, 85060X (October 17, 2012). https://github.com/nci/drishti/wiki