There are relatively few times these days when we encounter a dinosaur that we probably should have discussed previously but somehow we missed in the past. This week I noticed that we have somehow skipped a rather prominent dinosaur: Troodon formosus. Dated from 77 MA and originally recovered from the Judith River Formation of Montana. The first fossil was a tooth found in 1856 and described by Joseph Leidy (under the spelling Troödon), making Troodon one of the first North American dinosaurs found and described by Leidy, let alone anyone on the continent. These teeth were described as the teeth of a lizard initially. It was not until 1877 that the dental remains were redescribed and assigned to a place in the dinosaur family tree. The first skeletal remains recognizable as a dinosaur were discovered in the 1930's by Charles M. Sternberg in Alberta, Canada. Since that time many other skeletons and clutches of eggs attributed to Troodon have been discovered, recovered, and have been prepared. These remains have been discovered from a geographic range that includes Alaska, Wyoming, and potentially Texas or New Mexico; these finds are not conclusive at this time however.