Guest post: Gretchen Stokes, University of Florida Air-breathing fishes are those that respire using aerial gas exchange instead of, or in addition to, that of the water. Air-breathing is an ancient vertebrate specialization that evolved from aquatic hypoxia (e.g., areas of seasonally flooded wetlands, under ice). Air-breathing fishes are equipped with one or more modified respiratory … [Read more…]
Phylogeny is the representation of evolutionary relationships, often displayed as a “tree” (i.e., branching diagram) where the most closely related organisms are connected by a node and more distantly related organisms have multiple steps back in the tree before they are connected. Nodes are often characterized by biogeographic events and evolutionary innovations. In fishes, jawless … [Read more…]
Osteichthyes are a taxonomic grouping of bony fishes. This group includes ray-finned fishes (class: Actinopterygii) and lobe-finned fishes (class: Sarcopterygii). This highly diverse group of fishes, which contains almost all fish species, is the most diverse group of vertebrates today. Osteichthyes differ from chondrichthyes by (in most cases) possessing a bony skeleton, a swim bladder, … [Read more…]
This series of small bones links the swim bladder to the inner ear in Ostariophysian fish, including minnows, carp, catfishes, and characins. When a sound wave hits the swim bladder, the vibration is transferred through the Weberian apparatus to the auditory region of the inner ear. This action helps amplify sound and, as a result, … [Read more…]
The swim bladder is an air filled organ used by some fish to maintain buoyancy at a desired depth and produce or hear sound. Physostomous swim bladders are directly connected to the gastrointestinal tract so that fish with these swim bladders, such as herrings, must “gulp” air to inflate their swim bladder and “burb” or … [Read more…]