Discovery of Middle-Upper Triassic holothurian sclerites from Yongning,Guanling,Guizhou

The holothurian sclerite fossils recorded in the present paper are first found in the Middle-Up-per Triassic(Ladian-Canian)Zhuganpo Formation of the Guanling area,Guizhou,southwestern China.A total of 5genera and6species,including2unidentified species,are described.Another2unidentified taxa are shown in the plate.The characteristics of the historical distribution of the holothurian sclerites are de-scribed.The above-mentioned fossils indicate that the Zhuganpo Formation is the product of Late Triassic deposition.The discovery further enriches the content of the Guanling biota and provides new materials for the study of the taxonomy and evolution of Triassic holothurian sclerites of China.