The subterranean catfish provides insights into visual adaptations to the phreatic environment.

Vertebrate eyes share the same general organization, though species have evolved morphological and functional adaptations to diverse environments. Cave-adapted animals are characterized by a variety of features including eye reduction, loss of body pigmentation, and enhanced non-visual sensory systems. Species that live in perpetual darkness have also evolved sensory mechanisms that are independent of light stimuli.

Deep evolutionary origin of limb and fin regeneration.

Salamanders and lungfishes are the only sarcopterygians (lobe-finned vertebrates) capable of paired appendage regeneration, regardless of the amputation level. Among actinopterygians (ray-finned fishes), regeneration after amputation at the fin endoskeleton has only been demonstrated in polypterid fishes (Cladistia). Whether this ability evolved independently in sarcopterygians and actinopterygians or has a common origin remains unknown.