Please cite this article in press as: Xing, L.-D., et al., Theropod and possible ornithopod track assemblages from the Jurassic–Cretaceous boundary Houcheng Formation, Shangyi, northern Hebei, China. Palaeoworld (2013), http://dx.doi.org/10.1016/j.palwor.2013.10.002 ARTICLE IN PRESS +Model PALWOR-230; No. of Pages 9 Available online at www.sciencedirect.com ScienceDirect Palaeoworld xxx (2013) xxx–xxx Theropod and possible ornithopod track assemblages from the Jurassic–Cretaceous boundary Houcheng Formation, Shangyi, northern Hebei, China Li-Da Xing a,∗ , Yong-Qing Liu b , Hong-Wei Kuang b , Hendrik Klein c , Jian-Ping Zhang a , Michael E. Burns d , Jun Chen b , Ming-Wei Wang b , Jian Hu a a School of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China b Institute of Geology, Chinese Academy of Geological Science, Beijing 100037, China c Saurierwelt Paläontologisches Museum, Neumarkt, Germany d Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive, Edmonton, Alberta T6G 2E9, Canada Received 11 July 2013; received in revised form 19 September 2013; accepted 11 October 2013 Abstract Dinosaur track assemblages from the Houcheng Formation in the small continental Shangyi Basin of northern Hebei Province, China bridge a gap in the record of vertebrates from this unit and enrich our knowledge of ichnofaunas from the Jurassic–Cretaceous boundary. Their stratigraphic position between the Middle Jurassic Yan-Liao Biota and the Lower Cretaceous Jehol Biota gives them a special importance. New discoveries allow a re-assessment of theropod and possible ornithopod tracks that are present with several trackways. Seventy-three footprints were exam- ined and documented. Despite their smaller size, the tridactyl mesaxonic theropod tracks show morphological similarities with the ichnogenus Therangospodus known from the Upper Jurassic deposits of North America, Europe, and Central Asia. The possible ornithopod tracks lack an associated manus imprint, suggesting a bipedal trackmaker. These possible ornithopod tracks from the Houcheng Formation provide evidence for the presence of small basal ornithopods or basal Cerapoda in the Upper Jurassic–Lower Cretaceous in this region. The depositional environment was the margin of an extensive shallow lake with fluctuating water levels under seasonally dry climate. © 2013 Elsevier B.V. and Nanjing Institute of Geology and Palaeontology, CAS. All rights reserved. Keywords: Theropod tracks; Possible ornithopod tracks; Jurassic–Cretaceous boundary; Houcheng Formation; Shangyi 1. Introduction Vertebrate fossils from the Upper Jurassic–Lower Cretaceous Houcheng Formation (= Tuchengzi Formation) are rare; there- fore, the dinosaur tracks from these strata are important (Zhang et al., 2012) specifically because of their stratigraphic position between the Middle Jurassic Yan-Liao Biota (comprising the Jiu- longshan and Tiaojishan formations) and the Lower Cretaceous Jehol Biota (comprising the Zhangjiakou, Dabeigou, Yixian, and Jiufotang formations). Both biotas are famous for their feath- ered dinosaurs, primitive birds, mammals, pterosaurs, fishes, and insects. ∗ Corresponding author. Tel.: +86 139 107 33464. E-mail address: xinglida@gmail.com (L.-D. Xing). To date at least ten tracksites have been discovered in Houcheng/Tuchengzi Formation strata (Houcheng Formation from Hebei Province = Tuchengzi Formation from Liaoning Province). Abundant dinosaur tracks have been described, including those of theropods such as Anchisauripus isp. (Sullivan et al., 2009), Grallator type (Yabe et al., 1940; Shikama, 1942; Young, 1960; Zhang Y.Z. et al., 2004; Matsukawa et al., 2006; Fujita et al., 2007; Xing et al., 2011; Zhang J.P. et al., 2012), Megalosauripus isp. (Xing et al., 2011), Menglongipus (Xing et al., 2009), and Therangospodus isp. (Xing et al., 2011). Other known ichnofossils are rare theropod swim tracks (Xing et al., 2011) and a crouching trace (Xing et al., 2012), as well as the avian ichnite Pullornipes (Lockley et al., 2006). In 2012, hundreds of thyreophoran (cf. Deltapodus isp.), theropod, ornithopod, and sauropod tracks were discovered in Yanqing, Beijing (Zhang et al., 2012) (The present study shows that these thyreophorans can be interpreted as poorly-preserved 1871-174X/$ – see front matter © 2013 Elsevier B.V. and Nanjing Institute of Geology and Palaeontology, CAS. All rights reserved. http://dx.doi.org/10.1016/j.palwor.2013.10.002