冀西北尚义上侏罗统—下白垩统后城组恐龙足迹新发现及生物古地理意义*

简要报道了新近首次在冀西北张家口尚义地区发现的恐龙足迹。野外地质调查发现，恐龙足迹赋存于尚义晚中生代盆地侏罗系—白垩系后城组顶部。恐龙行迹呈近东西向展布，由数十个足迹构成。初步研究表明，造迹者分别属于兽脚类和蜥脚类恐龙，由西向东行进。足迹中包括兽脚类足迹70余个，组成数个行迹；蜥脚类足迹15个，构成1列行迹。蜥脚类足迹特征显示其可能属于游泳状的行迹。华北北部土城子组/后城组发育于燕辽生物群—热河生物群更替演化时期（晚侏罗世—早白垩世早期），以往在该时期沉积物中罕见脊椎动物骨骼化石。近年来华北北部土城子组/后城组中频繁发现的恐龙足迹表明，燕辽生物群—热河生物群更替演化时期发育着以恐龙为代表的脊椎动物群。该发现将有助于进一步了解土城子组/后城组沉积时期恐龙属种的多样性及其生物古地理环境。晚侏罗世—早白垩世早期沉积古地理和古生态环境及其与恐龙动物群发育的研究有助于揭示陆地生物群更替演化和环境的关系。

New discovery of dinosaur footprints in the Upper Jurassic-Lower Cretaceous Houcheng Formation at Shangyi,northwestern Hebei Province and its biogeographical implications

A number of dinosaur footprints have been discovered recently from the Upper Jurassic-Lower Cretaceous Houcheng Formation in Shangyi，Zhangjiakou，northwestern Hebei Province.The trackways and footprints display a east-west trend on the rock surface of the top of the Houcheng Formation.The preliminary research indicates that these trackways comprise theropod and probably swimming sauropod footprints.One trackway consisted of fifteen sauropod footprints and the other footprints cluster including more than seventy theropod footprints were both recognized.The Tuchengzi/Houcheng Formation was deposited in the transitional period from the Yanliao Biota to the Jehol Biota，which was previously considered as poor palaeogeography and palaeoecology and rare dinosaur bone fossils have been found.Frequent discoveries of dinosaur footprints from the Tuchengzi/Houcheng Formation in northern areas of North China suggest that vertebrate of dinosaur mainly was the survival in the transitional period from the Yanliao Biota to the Jehol Biota in the Late Jurassic-Early Cretaceous，and greatly enrich the knowledge on the diversity of dinosaur species and biogeography of the Tuchengzi/Houcheng Formation.Study on the palaeogeography，palaeoecology and dinosaurs in the Late Jurassic-Early Cretaceous is beneficial to reveal the enigma of replacement of terrestrial biotas and environment.