Article: Lower Devonian chonetoidean brachiopods from Bac Bo, North Viêt Nam
Recent investigations of the Lower Devonian fauna of North Viet Nam have provided abundant invertebrates, among which chonetoidean brachiopods are especially common. Their good preservation has allowed the revision of eight of the nine species described in the literature. The North Vietnamese chonetoidean fauna is mainly characterized by the diversity of representatives of the Family Strophochonetidae (stropochonetines and parachonetines), which includes nine species. Three new genera, namely Tulynetes, Bacbonetes and Cyrtochonetes, and two species, namely Bacbonetes janvieri and Chlupacina nariensis, are described. The occurrence of Perichonetes mirabilis, Chulpacina nariensis, and plicanoplitid brachiopods establishes the extension of the south west China pelagic Nandan facies to eastern Bac Bo. The Lower Devonian chonetoidean fauna of eastern Bac Bo is closely allied to that of south-west and central China belonging to the Yangtze microcontinent, whilst the fauna of western Bac Bo appears to be more closely allied with that of the northern Gondwanaland margin. One new additional chonetoidean genus, Orthochonetes, is described in a note added to the systematic section.