Coelacanth

The purpose of this book is to give an account of the life and times of a single species of fish, Latimeria chalumnae- the coelacanth (or are there now two species?). Before the discovery of the modern Latimeria, relationships of the coelacanths were thought to lie with the rhipidistians, a group of fossil fishes that many think are tetrapod ancestors. Hence, by looking at the modern coelacanth and assuming conservatism we may be able to reconstruct the life of the 'missing link' between fishes and tetrapods. The coelacanth is the only living animal to retain some structuralcharacteristics that were certainly present in the tetrapod ancestors, such as the intracranial joint. Therefore it is of some interest to try and find out how this joint works and what it is there for. The gene pool of the coelacanth has been separated from that of all other living vertebrates for at least 360 million years. Therefore, it is of some interest to find out how much deviation from contemporaneous fishes there has been. Coelacanths have often been used as the classic example of a particular evolutionary pattern whereby evolution is very fast in the early years and then slows down to stability and finally stagnation. This needs to be evaluated in the light of what we now know of the history of the coelacanths as a genetic lineage.