The use of spiracles in air breathing in Polypterus
Sagittal and transverse magnetic resonance images of Polypterus showing the path (arrows) of air through the spiracles to the buccopharyngeal chamber and lungs
Dorsal view of the skull of Polypterus in comparison to three stem tetrapods and three other early osteichthyans.
Graham J., Wegner N., Miller L., Jew C., Lai N., Berquist R., Lawrence F., Long J. (2014) Spiracular air breathing in polypterid fishes and its implications for aerial respiration in stem tetrapods. Nature Communications 5: 3022.