Fig. 4 in Function and evolution of ankylosaur dermal armor

Fig. 4. An osteoderm from the nodosaurid Edmontonia (DMNH 2452) from the Upper Cretaceous Hell Creek Formation of South Dakota. A. Photograph of the external surface of the specimen. B. Section and thin−section of an osteoderm, cut along indicated by dashed line in A. The thin−section was cut parallel to the ridge of the osteoderm. Pipe−like large vascular canals are extensively developed in the cancellous bone. An external cortex layer (dark gray) and an internal region (white) of cancellous bone can be seen. Photographs (B1, B2) and interpretive drawing (B3). C, D. Cortical bone tissue of the osteoderm. Detail of the cortex and inner trabecular bone in normal (C) and polarized (D) light; external surface is to the top. Many structural fiber bundles oriented perpendicular and parallel to the osteoderm surface occur within the cortex.