Stratigraphy, paleontology and age of the Fruitland and Kirtland Formations (upper Cretaceous), San Juan Basin, New Mexico Author Hunt, A. P. Author Lucas, S. G. text 1992 New Mexico Geological Society 43 rd Annual Fall Field Conference Guidebook Editor Lucas, S. G. Editor Kues, B. S. Editor Williamson, T. E. Editor Hunt, A. P. New Mexico Geological Society 217 239 book chapter 24289 10.5281/zenodo.3614972 c026b052-b7ca-498d-b55b-5b3c092d0c84 3614972 Ankylosaurs — Several localities in the Fruitland and Kirtland yield nodosaurid scutes. Keeled scutes of nodosaurids can be distinguished from ankylosaurids in that ankylosaurid scutes are commonly excavated on their medial surface and thus are thin ( Coombs and Maryanska, 1990 ). In contrast, nodosaurid scutes tend to be flat or only slightly cupped on their medial surface ( Coombs and Maryanska, 1990 ). NMMNH P-20880 ( Fig . 8 K-L) represents the first specimens of a nodosaurid reported from the Fruitland Formation. These specimens are thick, keeled plates with only slightly concave medial surfaces . NMMNH P- 1078 ( Fig . 8 I-J) is two large keeled plates of a nodosaur from the Naashoibito Member of the Kirtland Formation. These plates are similar to dorsal scutes of Edmontia ( Coombs and Maryanska . 1990, fig. 22.13 upper).