Two theropod track assemblages from the Jurassic of Chongqing, China, and the Jurassic Stratigraphy of Sichuan Basin

Abstract Four Jurassic dinosaur tracksites have been reported from Chongqing Municipality. These include the Lower Jurassic Dazu site in the Zhenzhuchong Formation, which yields the oldest sauropod trackway known from China. Two of the remaining three sites (Nan’an, and Jinji sites), variously regarded as Middle and Upper Jurassic, are here described in detail for the first time and regarded as Upper Jurassic, both from the Shangshaximiao Formation. The fourth site (Chengyu), so far not accessible to the present authors, is not described. The Nan’an site, and type locality of Chongqingpus nananensis, has yielded a large sample of theropod tracks from the heart of Chongqing Municipality, at a site that has been lost in the urban development. Fortunately the sample is preserved at Chongqing Museum of Natural History and has been studied independently on two occasions to produce the results presented here. C. nananensis is a medium-sized track (mean track length ~29 cm) that may best be accommodated in ichngenus Kayentapus, and may in some cases preserve ill-defined hallux traces. Associated tracks are attributed to cf. Anomoepus