Fresh specimens were frozen in solidifying propane at approximately −188°C and fractured under liquid nitrogen at −196°C in order to obtain clean, untouched surfaces. The specimens were then thawed in Karnowski solution and dehydrated in graded ethanol and hexamethyldisilazane.
Other fragments were briefly washed in 0.1 M phosphate buffer, thermally treated at 400°C for 24 h to remove the cells and the soft matrix and allowed to slowly return to room temperature.
All specimens were mounted on appropriate stubs with a colloidal silver glue, coated with 10 nm gold–palladium in an Emitech K550 sputter‐coater (Emitech) and observed with a FEI XL‐30 FEG high‐resolution SEM (now Thermo Fisher). Images were directly obtained as 8bpp, 1424 × 968 TIFF files.
Other fragments were briefly washed in 0.1 M phosphate buffer, thermally treated at 400°C for 24 h to remove the cells and the soft matrix and allowed to slowly return to room temperature.
All specimens were mounted on appropriate stubs with a colloidal silver glue, coated with 10 nm gold–palladium in an Emitech K550 sputter‐coater (Emitech) and observed with a FEI XL‐30 FEG high‐resolution SEM (now Thermo Fisher). Images were directly obtained as 8bpp, 1424 × 968 TIFF files.