Calcideletrix fastigata (Radtke, 1991)

Description. This very rare, substrate-parallel, dendritic boring system is characterised by dichotomously ramifying galleries, emerging from a central small cavity or elongated gallery of 5-8 µm in diameter, thereby slowly tapering towards their terminations (Fig. 9A-B). In addition, the galleries are occasionally connected to the substrate surface by tapering rhizoidal appendages (Fig. 9B). Moderate swellings are often present at the bifurcations and may additionally appear along the galleries.