Redescription of the cranial skeleton of the Early Devonian (Emsian) sarcopterygian Durialepis edentatus Otto, 2007 (Dipnomorpha; Porolepiformes)

Porolepiforms represent a clade of Devonian stem lungfishes, divided into the cosmine-bearing and likely paraphyletic ‘Porolepidae’ (e.g., Porolepis, Heimenia) and the cosmine-free and stratigraphically younger Holoptychiidae (e.g., Holoptychius, Glyptolepis, Laccognathus). Data on the dermoskeleton are available for both groups, but are more limited for ‘porolepids’. Here we present new information on the ‘porolepid’ Durialepis edentatus from the Emsian (Early Devonian) of Germany based on micro-CT scanning. The material comprises an articulated skull of a single three-dimensionally preserved individual. The arrangement of the cheekbones of Durialepis edentatus recalls that of Porolepis brevis, with the occurrence of two subsidiary squamosals. However, the parieto-ethmoidal and postparietal shields are roughly equal in size, a condition similar to that of Glyptolepis groenlandica and intermediate between Porolepis brevis and holoptychiids. A large parasymphysial tooth plate displays fi...