Best-known are the African species, which hibernate in hard clay balls during the dry season. They line their retreat with a waterproof membrane of dried mucus and apply their mouths to tubes of this material that serve as airshafts from the cocoons to the surface of the ground. They can remain dormant in this manner for up to three years. In water, the African lungfishes breathe with gills.
The South American loalach is totally dependent on air and will drown if held underwater. Its eggs are laid in a long tunnel at the bottom of a swamp and are guarded by the male, which sprouts red filamental gills from his pelvic fins. The young are also equipped with temporary external gills.
Lungfish are classified in the phylum Chordata , subphylum Vertebrata, class Sarcopterygii, order Ceratodontiformes, family Ceratodontidae, and order Lepidosireniformes, families Lepidosirenidae and Protopteridae.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.
See more Encyclopedia articles on: Vertebrate Zoology