birds and troodontids are closely related (Chure suggested that they may even have been sister taxa, though this is not currently supported). Within this context, Koparion could be used to refute the temporal paradox argument, that such a close relationship were unlikely because the then oldest known bird, Archaeopteryx, lived much earlier than the Deinonychosauria, i.e. the Troodontidae and the Dromaeosauridae; later also non-fragmentary Jurassic troodontid material was reported, from China. See also List of dinosaurs Hesperornithoides - Another troodontid reported from the Jurassic. Timeline of troodontid research References Late Jurassic dinosaurs of North America Troodontids Dinosaurs of the Morrison Formation Fossil taxa described in 1994 Paleontology in Utah