Barefins

Barefins are a group of primitive, lobe-finned fishes that represent an ancient lineage within the vertebrate evolutionary tree. They are characterized by their distinctive fleshy, lobed fins, which are supported by a skeletal structure resembling the limbs of tetrapods (four-limbed vertebrates). This anatomical feature has made them a subject of significant interest in studies of vertebrate evolution, particularly in understanding the transition from aquatic to terrestrial life.

The most well-known living barefin is the coelacanth (*Latimeria*), a deep-sea fish that was once thought to have been extinct for millions of years until rediscovered in 1938. Coelacanths belong to the order Coelacanthiformes and are found in the Indian and Pacific Oceans, inhabiting depths of up to 1,200 meters. Their discovery challenged long-held assumptions about evolutionary progress and highlighted the possibility of "living fossils" persisting in remote environments.

Another group of barefins is the lungfishes (Dipnoi), which are found in Africa, South America, and Australia. Unlike coelacanths, lungfishes possess both gills and a modified swim bladder that functions as a lung, allowing them to survive in oxygen-poor waters and even burrow into mud during dry periods. Their ability to breathe air has made them a key model for studying the evolution of terrestrial respiration.

Barefins are also linked to the extinct group of lobe-finned fishes known as rhipidistians, which are considered direct ancestors of early tetrapods. Fossil evidence, such as *Tiktaalik*, a transitional fossil from the Devonian period, shows intermediate traits between fish and amphibians, reinforcing the idea that barefins played a crucial role in the colonization of land by vertebrates. Their genetic and anatomical studies continue to provide valuable insights into the early stages of vertebrate evolution.