First discovery of dinosaur tracks from the Lower Cretaceous Duoni Formation in eastern Tibet, China

Abstract

Dinosaurs are known to have been abundant and diverse in eastern Tibet, and roamed the region from the Early Jurassic to the Late Cretaceous. Even though the evidence of dinosaurs is known throughout this interval, there are still many stratigraphic gaps that lack evidence, such as the Upper Jurassic and the Lower Cretaceous successions. Here, we report a new dinosaur tracksite from the Lower Cretaceous Duoni Formation of Basu County, where 28 track-bearing surfaces were discovered, which document a flourishing dinosaur community. Of these, three track layers with a high abundance of dinosaur tracks are described here, including sauropod, ornithopod and theropod trackways. These tracks suggest a possible exchange of trackmakers between this region and with adjacent areas of East Asia. The trackmakers' size, gait, and speed were inferred. The paleoenvironment is interpreted as ephemeral lakes bordered by conifer dominated forests. Palynological analysis conducted along the Duola stratigraphic section suggests that the tracksite is Aptian-Albian (Lower Cretaceous) in age, and the paleoclimate of the Basu area was relatively warm and dry.