A new dinosaur track site from the earliest Cretaceous (Berriasian) part of the Tuchengzi Formation, Hebei Province, China: Implications for morphology, ontogeny and paleocommunity structure

Abstract

The Jurassic-Cretaceous Tuchengzi Formation has yielded at least 16 known theropod-dominated tracksites from northeast China, and in this paper, a new locality, the Lishi site in Hebei Province, is documented. A tuff layer positioned stratigraphically 90 m below the trackway layer yielded a UPb date of 142.2 ± 0.9 Ma, placing the site in the Berriasian stage. The site includes sauropod tracks, assigned to Brontopodus, and large theropod tracks, informally assigned to Therangospodus and Megalosauripus as well as a well-preserved morphotype here named as Asianopodus wangi ichnosp. Nov. The Tuchengzi Formation theropod track assemblages have implications for theropod ontogeny, paleocommunity structure, palaeobiology and preferred habitats of different size groups, based on comparison with data from the skeletal record. The size-frequency distribution indicates that small theropod tracks (Footprint length, FL < 25 cm) represent the dominant trackmakers with estimated body masses of <100 kg, whereas intermediate sized trackmakers (FL 25.0 – ~38.0 cm) are comparatively scarce and there are no tracks suggestive of megatheropods with body masses of >1000 kg. The latter phenomenon is in contrast to recently published analyses from Cretaceous theropod skeletal data that recognize a gap between small and very large megatheropod individuals.