Abstract

The recent discovery of three different types of bird tracks from the Late Cretaceous (Campanian) Blackhawk Formation, Mesaverde Group, in east-central Utah marks the first report of unquestionable bird fossils from the Mesozoic of Utah. Bird tracks were found in Meetinghouse Canyon, northwest of Huntington, Utah, and in Straight Canyon, northwest of Orangeville, Utah. The Straight Canyon tracks were apparently made by two different types of birds, and a third type made the Meetinghouse Canyon tracks. Assignment of these ichnofossils to avian track makers is based on the wide angle of divarication between digits II and IV, the impression of the hallux (digit I), and other qualitative features. Dinosaur tracks are also present on slabs from about the same stratigraphic position as the Straight Canyon bird tracks. Some previously reported and unreported questionable bird tracks from the Blackhawk Formation are reevaluated, and their relationship to the toothed-bird family Hesperornithidae are discussed. As many as five different types of birds may be represented by tracks in the Blackhawk Formation.

Associated with the Meetinghouse Canyon bird tracks is a single set of footprints made by an anuran (frog or toad). The anuran tracks consist of both manus and pes prints, although the pes prints are incomplete. Mesozoic anurans have not been previously reported from Utah.