Evidence for lack of choanae in the Porolepiformes

New material from the Emsian (Lower Devonian) of Spitsbergen, consisting of lower jaws and the ethmosphenoid portion of skulls, allows the elucidation of the relations between the dermopalatine, the vomer and the ethmoid region in porolepiformes. It shows that the fenestra endochoanalis was certainly occluded by the ethmoidal process of the palatoquadrate and that a fenestra exochoanalis is not present between the vomer, dermopalatine, maxilla and premaxilla.