Fast-running theropods tracks from the Early Cretaceous of La Rioja, Spain

Abstract

Theropod behaviour and biodynamics are intriguing questions that paleontology has been trying to resolve for a long time. The lack of extant groups with similar bipedalism has made it hard to answer some of the questions on the matter, yet theoretical biomechanical models have shed some light on the question of how fast theropods could run and what kind of movement they showed. The study of dinosaur tracks can help answer some of these questions due to the very nature of tracks as a product of the interaction of these animals with the environment. Two trackways belonging to fast-running theropods from the Lower Cretaceous Enciso Group of Igea (La Rioja) are presented here and compared with other fast-running theropod trackways published to date. The Lower Cretaceous Iberian fossil record and some features present in these footprints and trackways suggest a basal tetanuran, probably a carcharodontosaurid or spinosaurid, as a plausible trackmaker. Speed analysis shows that these trackways, with speed ranges of 6.5–10.3 and 8.8–12.4 ms−1, testify to some of the top speeds ever calculated for theropod tracks, shedding light on the question of dinosaur biodynamics and how these animals moved.

Dots on a screen: The past, present, and future of morphometrics in the study of nonavian dinosaurs

“…In a landmark paper, Alexander (1976) used a variety of extant animals with known running speeds to relate speed, stride length, and hip height. As a result, measuring distances between tracks and track length has been a crucial component of characterizing track sites (e.g., Farlow, 1981; Kozu et al, 2017; Moreno et al, 2012; Navarro‐Lorbés et al, 2021). More recently, evolutionary robotics and biomechanical modeling approaches have been employed with body fossils to assess both gait and running speed (Bates et al, 2012; Hutchinson, 2004; Sellers & Manning, 2007).…”