The fossil, holotype TPII 2000-09-29, was donated to science by an anonymous benefactor. It is part of the collection of Thanksgiving Point Institute, Inc. and displayed in the North American Museum of Ancient Life at Lehi, Utah. It includes an incomplete skull and mandible (lower jaws) and much of the postcranial skeleton, i.e. the parts behind the head. The skull of Tanycolagreus is less well known than its postcranial anatomy, and only the following elements have been found: left nasal, left lacrimal, left premaxilla and one premaxillary tooth, left postorbital, left quadratojugal, incomplete left squamosal, right quadrate, right splenial, left articular, and two cheek teeth. A paratype has been assigned to the species: specimen AMNH 587 consisting of an incomplete hand also collected f