First report of sauropod tracks from the Upper Jurassic Tianchihe Formation of Guxian County, Shanxi Province, China

Abstract This paper presents the first report of sauropod tracks from the Upper Jurassic of Shanxi Province, China. Dinosaur tracks appear concentrated in five trackways, in different stratigraphic levels of the Late Jurassic Tianchihe Formation. Tracks are dominantly small and medium-size sauropod tracks and are tentatively assigned to Brontopodus based on preserved track morphology, trackway pattern and statistical analysis. The Tianchihe Formation in which the tracks appear shows a gradual change from meandering fluvial to sandy braided fluvial depositional systems developed in a seasonally arid environment. Comparisons of the evaluated speed of bipedal to quadruped trackways indicate that the slower walk more easily produces pes-dominated overprints. Trackways in the Guxian tracksite appear following different orientations, suggesting that these trackways were produced by different sauropods at different times. An unusual trackway following a curved pattern has been identified in the site and could represent a special locomotion character or a social behavior. The presence of eolian deposits in central Shanxi Province could have acted as a paleogeographic and paleoenvironmental barrier for the dispersion of the Yanliao Biota that survived in northern Hebei-western Liaoning and northestern Shanxi Province to the Ordos Basin during the Late Jurassic.