The Cretaceous strata of Zhejiang Province yielded abundant dinosaur bone, egg, and track fossils, documenting diverse terrestrial dinosaur assemblages in southeastern China. Herein we report new tridactyl theropod tracks from the mid-Cretaceous Chaochuan Formation at Shang’antian Village, Dongyang City, Zhejiang Province. Two distinct morphotypes of theropod tracks are identified, representing the first record of these ichnotypes in Zhejiang Province. Morphotype 1 is referred to Grallator isp., characterized by small, slender mesaxonic tracks with a high length/width ratio and narrow interdigital divarication. Morphotype 2 is referred to cf. Asianopodus isp., characterized by a prominent metatarsophalangeal pad aligned along the axis of digit III, a lower length/width proportion, and much wider interdigital angles compared with Grallator. Multiple parallel trackways of cf. Asianopodus isp. with consistent orientation and uniform spacing demonstrate gregarious behavior of small-sized arctometatarsalian theropods, likely ornithomimosaurs, during the mid-Cretaceous in southeastern China, representing only the second global record of group behavior in Asianopodus-type theropods. This new track assemblage enriches the Cretaceous dinosaur ichnofossil record of Zhejiang, provides new evidence for regional stratigraphic correlation, and offers new insights into the paleobiology, taxonomic composition, and behavioral ecology of southeastern Chinese mid-Cretaceous theropod communities.
