Fig. 6 in Function and evolution of ankylosaur dermal armor

Fig. 6. Osteoderms from the nodosaurid Sauropelta (DMNH 18206) from the Lower Cretaceous Cloverly Formation of Wyoming. A, B. External surface photograph of a large DMNH 18206−1 (A) and small DMNH 18206−2 (B) osteoderms. C, D. Thin−sections of osteoderms, cut along indicated by dashed lines C (in A) and D (in B). The thin−section was cut parallel to the ridge of the osteoderms. Dark gray, cortical bone consisting of woven or structural fiber bone; white, cancellous bone. Photographs (C1, D1) and interpretive drawings (C2, D2). E–H. Cortical bone tissue of osteoderms. E, F. Detail of the cortex and inner trabecular bone of large osteoderm (DMNH 18206−1) in normal light (E) and in polarized (F) light. G, H. Detail of the cortex and inner trabecular bone of small osteoderm (DMNH 18206−2) in normal (G) and polarized (H) light. External surface is to the top. Both osteoderms share identical histological features, despite the difference in size. Many structural fiber bundles occur within the cortex.