New acrotretacean brachiopods from the Palaeozoic of Britain and Austria

New acrotretacean brachiopods are described; Caenotreta aldridgei gen. et sp. nov. from the Llandovery of the Welsh Borderland, England, C. celloni sp. nov. from the Llandovery of the Carnic Alps, Austria and Caenotreta sp. from the late Silurian of the Carnic Alps. There are also new records from the Devonian of Germany. The possible ecology of these micromorphic conical forms is discussed