The lobefinned fishes are a group of bony fishes that have lobed fins. The vast majority of modern bony fishes are ray-finned fishes. The lobe-finned fishes are a paraphyletic group, meaning that they do not include all of the descendants of their common ancestor. This is because some of the lobe-finned fishes have evolved into tetrapods, which include amphibians, reptiles, birds, and mammals.
Lobefins first appeared during the Devonian period. They were a diverse group of fishes that included both marine and freshwater species. The lobe-finned fishes eventually gave rise to the tetrapods, which began to colonize the land during the Carboniferous period.
The key feature that distinguishes lobe-finned fishes from ray-finned fishes is the structure of their fins. The fins of lobe-finned fishes are made up of a central bone that is surrounded by fleshy tissue. This structure allows the fins to be used for a variety of purposes, including locomotion, support, and respiration.
Lobefins also have a number of other features that distinguish them from ray-finned fishes. These include:
* A well-developed skeleton
* A pair of lungs
* A heart with two chambers
* A kidney
* A liver
The lobe-finned fishes are an important group of fishes because they are the evolutionary ancestors of the tetrapods. Their adaptations for life in a variety of environments allowed them to colonize the land and give rise to the diverse array of land animals that we see today.