Revision of the Early and Middle Cambrian Acrotretids (Brachiopoda, Linguliformea) from the Siberian Platform

Resumo

This paper continues our revision of Yu.L. Pelman’s collection of the linguliformean brachiopods and of our own material from the Early–Middle Cambrian of the Siberian Platform (for previous papers see (Ushatinskaya and Korovnikov, 2014, 2016). The present paper focuses on the order Acrotretida. Linnarssonia, Homotreta, Prototreta, Opistotreta, and Kostjubella (family Acrotretidae) were restudied using the scanning electron microscope. Kostjubella (family Acrotretidae) and Erbotreta (family Ceratretidae) are described for the first time from the Siberian Platform. Some species described by Pelman are placed into synonymy. Two new species, Linnarssonia ulakhani and Erbotreta elankii, are established.