Figure 2. Specimen A28720 (Paleontologisk Museum, Oslo) preserving articulated remains of the heterostracan Protopteraspis vogti Kiaer (specimen A28720/2). A. Whole specimen showing the mouth of the heterostracan sitting with the recess resulting from mechanical preparation to reveal the oral plates. B. Montage of scanning electron photomicrographs of epoxy resin replica of the oral plates following acid preparation, consolidation, and silicon rubber moulding. C. Montage of scanning electron photomicrographs of epoxy resin replica, showing the oral plates in oblique anterior view. Scale bar 1 mm.