Virtual palaeontology: the effects of mineral composition and texture of fossil shell and hosting rock on the quality of X-ray microtomography (XMT) outcomes using Palaeozoic brachiopods

Abstract

X-ray microtomography (XMT) has become a popular tool for detailed investigations of a diverse range of fossils. However, XMT has not always guaranteed a satisfactory result, as the resolution of XMT images critically depends on the contrast between the fossil and its hosting rock. In this paper, XMT was applied to 11 Palaeozoic brachiopod specimens selected from a range of sedimentary rocks in order to investigate the extent of effects of mineral composition and texture in the rock and fossil shell on the quality of XMT outcomes. Our study shows that sufficient contrast in mineral composition and texture between the brachiopod shell and its infilling material is required to reproduce high-quality XMT results. Specifically, brachiopod specimens with their original calcium carbonate shell, infilled mainly with quartz grains, appear to produce the best XMT results characterized by sharply defined shell internal structures. We also found that diagenesis is significant in determining the XMT quality. Diagenetic processes including silicification and recrystallization in the brachiopod shell and/or the infilling material generally tends to diminish the resolution of the XMT results, although this impact is considerably complicated by the degree and aspect of diagenesis. Another factor of minor significance concerns the presence of bioclasts scattered in the hosting sediment that potentially could be confused with genuine shell internal structures.

State of knowledge and correlation potential of Mississippian brachiopods of the western slope of the northern Urals

“…При этом существует зависимость от соотношения «раковина -порода» со смешанным карбонатно-глинистым наполнителем. Например, спирифирида Tylothyris transversa Roberts, 1971 из турнейских отложений Австралии показала худшие изображения по сравнению с пермской брахиоподой Cleiothyridina baracoodensis (Etheridge) (Lee et al, 2017). Другими недостатками метода являются отсутствие визуализации линий роста, ограничения по размеру выборки и довольно высокая стоимость используемого оборудования.…”

Ex Vivo Three-Dimensional Reconstruction of Acutiramus: A Giant Pterygotid Sea Scorpion

“…This reflects the more frequent application of methods like computed tomography that permit reconstruction of fossils in three dimensions (3D) (Hohenstein, 2004; Sutton, 2008; Scherf, 2013; Sutton et al, 2014; Johnson and Carter, 2019). These approaches have permitted the virtual dissection of fossils from rock or amber (Sutton, 2008; Perreau and Tafforeau, 2011) and the illustration of specimens in 3D (Cunningham et al, 2014; Jauvion et al, 2016; Lee et al, 2017)—a direction that is especially useful in documenting holotype material for global dissemination (Garwood et al, 2011; Garwood and Dunlop, 2014; Ashe-Jepson et al, 2019; Bicknell et al, 2022a). This expansion of virtual paleontology has also resulted in a synthesis between paleontology and 3D computational methodologies, such as fluid-dynamic and kinematic approaches (Rayfield, 2007; Anderson and Westneat, 2009; Cunningham et al, 2014; Brassey et al, 2017).…”

Comparison of methods: Micro-CT visualization method and epoxy cast-embedding reveal hidden details of bioerosion in the tube walls of Cretaceous polychaete worms

“…Micro-CT devices utilize X-rays to see inside an object, enabling virtual three-dimensional reconstruction of the specimen, and generation of videos using individual section images. It is intensively used for study of recent (Mees et al, 2003;Beuck et al, 2006;Schönberg and Shield, 2008;Lukeneder and Lukeneder, 2011;Lukeneder, 2012;Lukeneder et al, 2014;Amon et al, 2015;Färber et al, 2016;Silbiger et al, 2016) and fossil bioerosional traces (e.g., Benner et al, 2008;Beuck et al, 2008;Lee et al, 2017;Wisshak et al, 2017;Heřmanová et al, 2020). In our study, we used a combination of micro-computed tomography and vacuum cast-embedding technique producing polymer resin casts followed by SEM observations to visualize bioerosion inside serpulid polychaete tubes.…”