| Bivalves from the Sella Formation (middle Arenig, Tarija, Bolivia) are described and illustrated. The taxa recognized are Hemiprionodonta lusitanica (Sharpe), known from southern Europe (Spain, Armorican Massif, Montagne Noire), Redonia riojana Sánchez from the west-Argentina Famatina basin, and the new species Coxiconchia sellaensis . These species support the paleobiogeographic affinities between the south European (Armorica), Bolivian and west Argentine basins and corroborate the development of an extensive and continuous shelf throughout the northwest margin of Gondwana during the Arenig. Additionally, specimens at different stages of dental development of Natasia boliviensis (Babin and Branisa) are reported. |
