Micro-computed tomography: Introducing new dimensions to taxonomy

Abstract

Continuous improvements in the resolution of three-dimensional imaging have led to an increased application of these techniques in conventional taxonomic research in recent years. Coupled with an ever increasing research effort in cybertaxonomy, three-dimensional imaging could give a boost to the development of virtual specimen collections, allowing rapid and simultaneous access to accurate virtual representations of type material. This paper explores the potential of micro-computed tomography (X-ray micro-tomography), a non-destructive three-dimensional imaging technique based on mapping X-ray attenuation in the scanned object, for supporting research in systematics and taxonomy. The subsequent use of these data as virtual type material, so-called “cybertypes”, and the creation of virtual collections lie at the core of this potential. Sample preparation, image acquisition, data processing and presentation of results are demonstrated using polychaetes (bristle worms), a representative taxon of macro-invertebrates, as a study object. Effects of the technique on the morphological, anatomical and molecular identity of the specimens are investigated. The paper evaluates the results and discusses the potential and the limitations of the technique for creating cybertypes. It also discusses the challenges that the community might face to establish virtual collections. Potential future applications of three-dimensional information in taxonomic research are outlined, including an outlook to new ways of producing, disseminating and publishing taxonomic information.

The pros and cons of using micro-computed tomography in gross and microanatomical assessments of polychaetous annelids

“…Given that X-rays are a core tool for human medicine, this suggests that use of micro-CT may have limited impact on genetic material. Trials using bird specimens did not find any discernible effects (Paredes et al, 2012) and tests on polychaete material also failed to show any major impact, at least for the 16S rRNA gene (Faulwetter et al, 2013). These results indicate that -at least with commonly used scanning parameters -there should be no impediment to using this approach on specimens in museums.…”

“…The resulting files, both original image stacks and rendered images are standard image files and thus can be distributed without compatibility problems between researchers. CT rendering can also be embedded within PDFs (see Faulwetter et al 2013 for an example), which enables readers to examine and interact with the images produced. It is also possible that rendered images of type specimens could be sent as virtual loans instead of delicate specimens.…”

“…This study complements that of Faulwetter et al (2013), focussing on the use of micro-CT for internal anatomical studies.…”

“…Their use in anatomical studies of non-human subjects is increasing and there have been several studies focused on polychaetes. For example, Dinley et al, (2009) showed how the method could be used in functional anatomical studies, while Faulwetter et al (2013) have shown how the rendered micro-CT images provide detailed taxonomic results.…”

X‐ray computed tomography and its potential in ecological research: A review of studies and optimization of specimen preparation

“…Fields such as taxonomy (Akkari, Enghoff, & Metscher, 2015; Faulwetter, Vasileiadou, Kouratoras, Dailianis, & Arvanitidis, 2013; Fernández, Kvist, Lenihan, Giribet, & Ziegler, 2014) and morphology (Mattei, Riccio, Avila, & Wolfner, 2015; Wipfler et al., 2016) have greatly benefited from μ‐CT technique. However, most studies to date have focused on in‐depth studies of single individuals, and organisms′ responses to environmental drivers were only rarely considered.…”