Les vertébrés (Placodermi, Galeaspida) du Dévonien inférieur de la coupe de Lung Cô-Mia Lé, Province de Hà Giang, Viêt Nam, avec des données complémentaires sur les gisements à vertébrés du Dévonien du Bac Bo oriental

The vertebrates of the Si Ka, Bac Bun and Mia Lé formations (Lower Devonian, Lochkovian-Pragian) of the Lung Cô-Mia Lé section (Hà Giang Province, northern Vietnam) are represented by some galeaspid, arthrodire and antiarch remains, and by a new petalichthyid, Tongdzuylepis vietnamensis n.g., n.sp. The faunal list of the Khao Lôc Formation (Lower Lochkovian) at Tòng Vài (Hà Giang Province) is completed by the description of a galeaspid, Laxaspis yulongssus, and three antiarchs, Heteroyunnanolepis qujingensis, Zhanjilepis aspratilis and Minicrania lissa n.sp. A new antiarch, Yunnanolepis spinulosa n.sp., associated with Chuchinolepis dongmoensis and Youngolepis sp., is described from the transition beds between the Si Ka and Bac Bun formations at Ban Nhuân (Thái Nguyên Province, northern Vietnam). A complementary description and taxonomic comments are made for the galeaspids and antiarchs of the Bac Bun Formation at Dông Mo (Lang Son Province, northern Vietnam). Finally, a new sarcopterygian, Langdenia campylognatha n.sp. is described from the Bac Bun Formation at Trang Xa (Thái Nguyên Province).