The Devonian vertebrates (Placodermi, Sarcopterygii) from Central Vietnam and their bearing on the Devonian palaeogeography of Southeast Asia

Abstract

New vertebrate remains are described from the terrigenous facies of the Givetian Dong Tho Formation in Quang Binh Province, central Vietnam. They are referred to three placoderm groups, the Antiarchi, Arthrodira and Acanthothoraci, and to a sarcopterygian. The antiarchs are represented by a new form, Vukhuclepis lyhoaensis n.g. n.sp, which is regarded here as closely related to the Yunnanolepididae, an endemic group from the Lower Devonian of the South China Block. Additional material of the phlyctaeniid arthrodire Lyhoalepis duckhoai Tong-Dzuy Thanh, Janvier and Doan Nhât Truong is described. The sarcopterygian is regarded here as a dipnomorph, and may be closely related to the Lower-Middle Devonian Youngolepididae of the South China Block. This material confirms the close ties between the Indochina and South China blocks as early as the Middle Devonian.