Comparison of footprint length to footprint width (FL/FW) ratios of the Limiavipedidae, theropod traces, and traces of Mesozoic, Cenozoic, and extant birds.

Comparing footprint length to footprint width ratio (FL/FW) of Wupus agilis to the large avian trace Limiavipes curriei (Limiavipedidae) and to the Cretaceous theropod traces Irenichnites gracilis (small), Columbosauripus ungulates and Magnoavipes (M. lowei, M. caneeri, M. denaliensis) (medium), and Irenesauripus mcclearni (large), and traces of large Mesozoic, Cenozoic, and extant avians. There is considerable overlap in FL/FW values between theropod and avian traces, making FL/FW an unreliable metric when used alone to distinguish between large avian and small theropod footprints.
Comparison of footprint length to footprint width (FL/FW) ratios of the Limiavipedidae, theropod traces, and traces of Mesozoic, Cenozoic, and extant birds.