Chondrophiidae

Chondrophiidae is a family of ancient live-bearing fish that are now considered to be extinct. They are characterized by the presence of a series of small, oxygen-spinning organs known as chondrophores in their heads, hence their name. Chondrophiidae are thought to have originated in the ancient world, with fossil evidence dating back as far as the Early Cretaceous period, although the exact timing of their emergence and extinction is still a subject of scientific debate.

The most well-known members of the Chondrophiidae family are the ratfish, or ceratioid fish, which are characterized by their chondrophores and the lack of bony fin rays in their dorsal and anal fins. The ratfish were thought to be among the first vertebrates to give birth to live young, rather than laying eggs, and were a key transitional form between the ancient lampreys and later more advanced groups of ray-finned fish.

Despite their fascinating evolutionary history, Chondrophiidae are relatively poorly understood, with many aspects of their biology and ecology remaining unclear. Fossil evidence is limited, and little is known about their habits, diet, or interactions with the environment. However, research continues to shed new light on this enigmatic family of ancient fish, and their study provides valuable insights into the evolution of vertebrates and the development of more complex forms of life on Earth.

Chondrophiidae are classified as part of a broader group known as the Neoselachii, a subgroup of sharks and rays that emerged in the Triassic period. As such, they are closely related to more familiar modern species of sharks and rays, although they occupy a unique position in the evolutionary tree due to their specialization of live birth and absence of bony fin rays.