Assertion: internal gill | /r/HasProperty | coates
Facets:
Source sentences:
text: However, the operculum may have disappeared before the internal gills (Coates and Clack, 1991).
text: Acanthostega, a Devonian stegocephalian, still had internal gills (Coates and Clack, 1991), and Ichthyostega may have retained them too, but no other stegocephalian is known to have had them.