Three-dimensionally preserved appendages of the early Cambrian trilobite Yunnanocephalus yunnanensis 1Yunnan Key Laboratory for Palaeobiology, Institute of Paleontology, Yunnan University, Kunming, China 2MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Kunming, China 3Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, United States of America 4Bavarian State Collection of Zoology,...