Rare, .48" Serrated Troodontid (Troodon) Tooth - Wyoming

About Troodon formosus

Troodon formosus was a small theropod dinosaur named from a distinctive tooth discovered in the Late Cretaceous deposits of Montana. The name Troodon, meaning “wounding tooth,” refers to the tooth’s prominent serrations, which initially led to considerable uncertainty about the animal’s relationships. For much of the 20th century, Troodon was reconstructed as a lightly built, bird-like predator with large eyes, long hind limbs, grasping hands, and a relatively large braincase. These features helped make it one of the most recognizable small theropods from Late Cretaceous North America.

However, the validity of Troodon formosus has become highly controversial. Because the species was originally established from an isolated tooth, its type specimen lacks many of the anatomical features needed to confidently associate it with more complete troodontid skeletons. Research has subsequently shown that several fossils historically assigned to Troodon likely represent distinct genera, including Stenonychosaurus and Latenivenatrix. As a result, many paleontologists now regard Troodon formosus as a dubious species, or nomen dubium, while Troodontidae remains a valid family of small, feathered, bird-like theropod dinosaurs.

About The Lance Formation

The Lance Formation of eastern Wyoming is a Late Cretaceous (69–66 million years old) unit that represents the same geologic age as the famous Hell Creek Formation of Montana and the Dakotas. Although they are time-equivalent, the Lance and Hell Creek preserve subtly different environments. Hell Creek reflects a humid, forested coastal plain punctuated by volcanic ash deposits, while the Lance records a slightly drier, more open floodplain landscape with broader river systems and fewer ash layers. Together, they provide a complementary view of life in the final chapter of the dinosaur era.

Perhaps the most famous Lance resident would be Tyrannosaurus rex, the largest North American carnivore to ever live. However, other smaller theropods also roamed the American midwest in this subtropical coastal stream system, including the beaked Ornithomimus, a lanky running theropod with a build similar to a modern ostrich, as well as several small predatory troodonts such as Paronychodon and Pectinodon.

Herbivorous dinosaurs also took advantage of the abundance offered by this unique era. Armored ankylosaurs dwelt in herds, their safety assured by their numbers, their heavy bone plating protecting most of their bodies and even their eyelids, and huge bone clubs on the ends of their tails providing them with powerful offensive capabilities. Ceratopsians like the famous Triceratops also formed protective herds, guarding their necks with frills and horns. Their smaller relatives, the dome-headed pachycephalosaurs, were also well represented in the area. Hadrosaurs, duck-billed titans with huge batteries of plant-grinding teeth in elongated snouts, are also well known from the region.

In addition to dinosaurs, a wide variety of fishes, amphibians, lizards, snakes, turtles, champsosaurs, crocodilians, and pterosaurs have been found in the formation.