A micro X-ray computed tomography dataset of fossil echinoderms in an ancient obrution bed: a robust method for taphonomic and palaeoecologic analyses

Abstract

Background Taphonomic and palaeoecologic studies of obrution beds often employ conventional methods of investigation such as physical removal and extraction of fossils from their host rock (matrix) by mechanical preparation. This often-destructive method is not suitable for studying mold fossils, which are voids left in host rocks due to dissolution of the original organism in post-depositional processes. Findings Microcomputed tomography (µCT) scan data of 24 fossiliferous rock samples revealed thousands of Paleozoic echinoderms. Digitally "stitching" together individually µCT scanned rock samples within three-dimensional (3D) space allows for quantifiable taphonomic data on a fossil echinoderm-rich obrution deposit from the Devonian (Emsian) of South Africa. Here, we provide a brief step-by-step guide on creating, segmenting, and ultimately combining sections of richly fossiliferous beds to create virtual models suited for the quantitative and qualitative taphonomic analyses of fossil invertebrate assemblages. Conclusions Visualizing the internal features of fossiliferous beds in 3D is an invaluable taphonomic tool for analyzing delicate fossils, accounting for all specimens irrespective of their preservation stages and with minimal damage. This technique is particularly useful for analyzing fossiliferous deposits with mold fossils that prove to be difficult to study with traditional methods, because the method relies on the large density contrast between the mold and host rock.

ADMorph: A 3D Digital Microfossil Morphology Dataset for Deep Learning

“…The 2D images are collected using a digital camera mounted on a microscope or scanning electron microscope. Few other datasets, such as echinoderm datasets [21] and planktonic datasets [19], are used in 3D imaging methods such as CT scanning. However, in these datasets, 3D fossil models except 2D slices are not provided.…”

An earliest Triassic age forTasmaniolimulusand comments on synchrotron tomography of Gondwanan horseshoe crabs

“…, Metscher, 2009 ; Haszprunar et al, 2011 ; Deans et al, 2012 ; Beutel et al, 2019 ; Willsch et al, 2020 ; MacDougall et al, 2021 ; Stillwell et al, 2020 ). In palaeontology, 3D data has been used widely in the visualisation of fossils preserved in amber ( Lak et al, 2008 ; Perrichot et al, 2008 ; Riedel et al, 2012 ; Xing et al, 2016a ; Xing et al, 2016b ; Xing et al, 2018 ; Daza et al, 2020 ; Bolet et al, 2021 ) and also in the examination of fossils that are still surrounded in their original rock matrix ( Moreau et al, 2014 ; Schwarzhans et al, 2018 ; Reid et al, 2019 ; Mayr et al, 2020 ).…”

Peer Review #2 of "An earliest Triassic age for Tasmaniolimulus and comments on synchrotron tomography of Gondwanan horseshoe crabs (v0.1)"

“…This precludes the need for physical dissection and/or preparation of specimens, which is relevant when describing structures from rare or fragile material (e.g., Metscher, 2009;Haszprunar et al, 2011;Deans et al, 2012;Beutel et al, 2019;Willsch et al, 2020;MacDougall et al, 2021;Stilwell et al, 2020). In palaeontology, 3D data has been used widely in the visualisation of fossils preserved in amber (Lak et al, 2008;Perrichot et al, 2008;Riedel et al, 2012;Xing et al, 2016aXing et al, , b, 2018Daza et al, 2020;Bolet et al, 2021) and also in the examination of fossils that are still surrounded in their original rock matrix (Moreau et al, 2014;Schwarzhans et al, 2018;Reid et al, 2019;Mayr et al, 2020).…”