An unusual dinosaur track assemblage from the Jurassic–Cretaceous boundary, Anning formation, Lufeng Basin, China

Abstract

ABSTRACT Late Jurassic dinosaur track assemblages from China are much less common than those reported from the Lower and Middle Jurassic which are heavily dominated by well-known theropod ichnogenera such as Grallator, Eubrontes, Kayentapus, and a few sauropodomorph and ornithischian ichnotaxa. We here report two tridactyl dinosaur morphotypes from the Lufeng Basin in southern China that most closely resemble Late Jurassic Dinehichnus from North America, a probable gracile ornithopod morphotype, and an unnamed avian morphotype reported from rare occurrences in North America and Europe, which we here name as Tridentigerpes ichnogen. nov., accommodating two ichnospecies T. huasibanleei ichnosp. nov. from the Lufeng Basin, and T. pinuelai ichnosp nov., from Spain. These ichnites re-orient our understanding of Late Jurassic dinosaur track distributions in the Late Jurassic of China, which was previously based in large part on very poor material of presumed theropod affinity. Given the sparse body fossil record from southern China including very fragmentary sauropod remains, the ichnological record of diverse bipedal dinosaurs, suggestive of avian and non-avian dinosaurs and ornithopods, the Anning Formation represents a type 2b deposit where tracks are more common than skeletal remains and indicative of faunas not represented by the body fossil record.