1. Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island 02912, USA
2. Department of Organismic and Evolutionary Biology, and Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts 02138, USA
3. Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA

Correspondence to: Stephen M. Gatesy¹ Correspondence should be addressed to S.M.G. (e-mail: Email: Stephen_Gatesy@Brown.edu).

Abstract

Dinosaur footprints have been used extensively as biostratigraphic markers, environmental indicators, measures of faunal diversity and evidence of group behaviour^{1, 2, 3, 4},. Trackways have also been used to estimate locomotor posture, gait and speed^{6, 7, 8, 9, 10, 11}, but most prints, being shallow impressions of a foot's plantar surface, provide little evidence of the details of limb excursion. Here we describe Late Triassic trackways from East Greenland, made by theropods walking on substrates of different consistency and sinking to variable depths, that preserve three-dimensional records of foot movement. Triassic theropod prints share many features with those of ground-dwelling birds, but also demonstrate significant functional differences in position of the hallux (digit I), foot posture and hindlimb excursion.