MicroCT scans of freshly fixed and museum earthworm specimens.

<br> Micro-computed tomography (µCT), a digital X-ray-based imaging technique, has developed into an important tool for the study of animal morphology. Although molecular tools are increasingly employed to decipher invertebrate systematics, earthworm (<em>Annelida: Clitellata: 'Oligochaeta'</em>) taxonomy is still largely based on conventional dissection, resulting in data that are mostly unsuitable for dissemination through online databases. In order to evaluate if µCT in combination with soft tissue staining techniques could be used to expand the existing set of tools available for studying internal and external structures of earthworms, µCT scans of freshly fixed and museum specimens were collected.<br> Scout images revealed full penetration of tissues by the staining agent. The attained isotropic voxel resolutions permit identification of internal and external structures conventionally used in earthworm taxonomy. The projection as well as the reconstruction images are archived here and are publicly available for download.<br> The dataset presented shows that earthworms constitute suitable candidates for CT scanning in combination with soft tissue staining. Not only are the data comparable to results derived from traditional dissection techniques, but they also permit interactively exploring earthworm morphology and anatomy. The approach pursued here can be applied to freshly fixed as well as museum specimens, which is of particular importance when considering the use of rare or valuable museum material.<br> <br>