The first record of Cretaceous mammaliaform and dinosaur track assemblages from South China

Lida Xing ^1,2,3, Jialin Mi ⁴, Jens N. Lallensack ⁵, Qiyan Chen ², Hendrik Klein ⁶, Qi Qi ², Lin Liu ², Chang Liu ⁷ & Hang Yin ^2
1State Key Laboratory of Geomicrobiology and Environmental Changes, China University of Geosciences, Beijing, China., ²School of Earth Sciences and Resources, China University of Geosciences, Beijing, China., ³Dinosaur Odyssey Science Museum, Guangxi, China., ⁴Department of Sports and Leisure, College of Culture, Arts and Sports, Honam University Gwangju, Korea., ⁵Departamento de Ciência da Computação, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil., ⁶Saurierwelt Paläntologisches Museum, Neumarkt, Germany., ⁷School of Geosciences, University of Edinburgh, UK.

Body fossils of Mesozoic mammaliaforms are rare, but their tracks are even rarer. We here describe a probable isolated mammaliaform or tritylodontid track from the Cretaceous of South China. This track is comparable to the ichnotaxa on Chelichnopodidae, and is the first mammaliaform track from South China. The track is a recent discovery at the Huaiji site, which was first described in 2023 and either belongs to the Mawu Formation (Albian– Cenomanian) or the Lailong Formation (Lower Cretaceous), Zhagang Group. Other tracks discovered at the site are described herein, including a theropod track that is closely similar to the Grallator morphotype or cf. Asianopodus isp. and two oval impressions that might represent the tracks of a quadruped, possibly a sauropod or a thyreophoran. Currently, the Huaiji site represents the southernmost and most diverse vertebrate ichnofauna in China.