MEd Student
Advisor: Gerhard Steiner

Unit for Integrative Zoology, Department of Evolutionary Biology
University of Vienna

Abstract

Earthworms have long been known for their contribution to the soil ecosystem’s structure. The taxonomy of earthworms, however, has undergone several cycles of reorganisation that are still ongoing. Earthworm identification requires time-consuming dissection and interpretation of morphological features that are often difficult to observe. This method requires a high degree of expertise and restricts the use of museum specimens. The analysis of micro-CT-scans of earthworms, however, is a non-destructive technique that allows to observe and reconstruct morphological features relevant for species identification in great detail. Therefore, this project aims to generate micro-CT-scans of Central European lumbricid earthworm species and contribute to the resolving of taxonomic inconsistencies within earthworm taxonomy. Earthworms from three habitats in Vienna were collected by handsorting. The posterior segments of each specimen were stored in 95% ethanol as a preparation for DNA-barcoding. The specimens were fixed with either 4% formaldehyde or Bouin’s fluid. Subsequent to macroscopic identification, specimens of the most common species (Octolasium cyaneum, Allolobophora calinginosa and Fitzingeria platyura) were stained with 0.3% PTA (phosphotungstic acid) and scanned with a voxel resolution of 9µm using a SkyScan 1272 µCT scanner. Using the software Amira, 2D section planes and 3D renderings of morphologically relevant features were generated. First results show that the images generated through micro-CT-scans offer a non-invasive method to visualize surface structures and the internal organs crucial for genus diagnostics and species identification.