Article: The Permian leiopteriid Merismopteria and the origin of the Pteriidae

The musculature and dentition of Merismopteria Etheridge jun. 1892 are described and illustrated. Muscles are present both in front and behind the 'clavicle' or buttress ridge. Lateral and cardinal teeth may be present. Merismopteria is closely related to and may be a synonym of Leiopteria Hall 1883. Modern pteriids are considered to be derived from the Palaeozoic leiopteriids which lack a chondrophore and have a flattish ligament area with chevron-shaped or parallel-longitudinal ligament grooves and it is concluded that the 'pteriid' type of ligament with a chondrophore is independently developed in the pterioids and the pectinoids.