consists of interbedded sandstone, siltstone, mudstone, coal and shale. The Kirtland Formation lies on the western margin of the Western Interior Seaway and represents a floodplain that was abundant with ferns, conifers and flowering plants. Based on the abundance of angiosperms with leaves that have entire or nearly entire margins and drip points, the Kirtland Formation may have had a warm temperate to subtropical climate. The Kirtland Formation was better drained than the underlying Fruitland Formation due to the lack of coal swamps. Ahshislepelta coexisted with the pachycephalosaurid Stegoceras, the chasmosaurine ceratopsids Navajoceratops and Terminocavus, the ankylosaurine ankylosaurid Ziapelta, the eutyrannosaur tyrannosauroid Bistahieversor, and the azhdarchid pterosaur Navajodactylus. See also Timeline of ankylosaur research References Late Cretaceous dinosaurs of North America Ankylosaurs Fossil taxa described in 2011 Paleontology in New Mexico Campanian genus first appearances Campanian genus extinctions Ornithischian genera