The Coelacanth Latimeria chalumnae

  • The class Osteichthyes (bony fish) is divided into two subclasses: ray-finned (Actinopterygii) and lobe-finned (Sarcopterygii). There are only four living genera of lobe-finned fish, but the group is known from fossils that date back to the very beginning of the class, 400 million years ago in the Devonian period. The paired fins of the lobe-finned fish are thought to have given rise to the limbs of the tetrapods.
  • The living lobe-finned fish include 3 genera of lung-fish, one of each in Australia, Africa and South America. The remaining genus contains one species, the coelacanth.
  • Discovered in the western Indian Ocean in 1938, the coelacanth represents a group of fishes that had been thought to be extinct for about 70 million years.
  • Recent comparisons of mitochondrial DNA have shown that lung-fishes are more closely related to the terrestrial tetrapods than are coelacanths. Therefore, many of the features that were supposed to link the living coelacanth with terrestrial tetrapods probably result from convergent evolution.
  • The museum has a life-sized cast made from a real coelacanth.
Coelacanth


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