Definition that contains external gill
- siren eellike aquatic North American salamander with small forelimbs and no hind limbs; have permanent external gills
- olm European aquatic salamander with permanent external gills that lives in caves
- mud puppy aquatic North American salamander with red feathery external gills
- necturus maculosus aquatic North American salamander with red feathery external gills
- proteus anguinus European aquatic salamander with permanent external gills that lives in caves