lingually, with no mesial serrations and 3 distal serrations per millimeter and is 12 mm in total length. There are three lingual ridges and four labial ones. Currie & Evans, 2019 diagnosed Zapsalis from Saurornitholestes by noting the type of the former is lacking mesial serrations and being concave apicodistally, and therefore "recommended that the two genera be kept separate." The second premaxillary teeth of Zapsalis and other dromaeosaurids may have been structurally specialized for preening feathers, as seen in some Oviraptorosaurs as well. Paleoenvironment All 4 named species are known from the Judith River Formation, the site of expeditions first by Edward Drinker Cope's crews during the early stages of the Bone Wars, including the discoveries of many taxa that he named, though all are now seen as dubious. These include fossils of large, carnivorous tyrannosaurid theropods like Aublysodon and Deinodon. As for the herbivorous Ornithischians, like the beaked hadrosaurids Trachodon and Cionodon were named. The most common fossils are those of the horned Ceratopsians like Monoclonius, Ceratops, and Pteropelyx. Lastly, the armored ankylosaur Palaeoscincus is known from scattered teeth. See also Timeline of dromaeosaurid research References Eudromaeosaurs Late Cretaceous dinosaurs of North America Fossil taxa described in 1876 Taxa named by Edward Drinker Cope Paleontology in Montana Paleontology in Alberta Campanian genus first appearances Campanian genus extinctions