The fossil specimen was documented with macro-photography, stereo-photography and fluorescence micro-photography to extract as much information as possible from it. The lepadomorph nauplius was documented with macro-photography. The balanomorph nauplius was documented with fluorescence micro-photography. The rhizocephalan nauplius was documented with scanning electron microscopy.
Macro-photography and stereo-photography combined with composite imaging were performed (following e.g. Haug et al., 2012; 2013a), both under cross-polarized light. We used a Canon EOS Rebel T3i camera with Canon MP-E (65 mm) macro lens. Illumination was provided by the Canon Macro Twin Lite MT-24EX flash from two opposing sides. Fluorescence microscopy of the fossil was performed on an inverse fluorescence microscope BZ-9000 (BIOREVO, Keyence) with about 40 times magnification recording autofluorescence under blue light (GFP, 488 nm; for details on autofluorescence imaging, see Haug et al., 2011b). Fluorescence microscopy on the balanomorph nauplius was performed on a Zeiss AxioScope 2 with about 200 times magnification recording autofluorescence under UV light (DAPI, 358 nm). For macro-photography and micro-photography stacks of images (of different focal planes) were recorded to overcome limited depth of field. Adjacent stacks were recorded to overcome limitations in field of view. Scanning electron microscopy of the rhizocephalan nauplius was performed on a JEOL 6335-F scanning electron microscope at the Zoological Museum in Copenhagen.