1857, from Modern Latin Coelacanthus (genus name, 1839, Agassiz), from Greek koilos "hollow" (from PIE root *kel-; see cell) + akantha "spine" (see acrid). So called from the hollow fin rays supporting the tail. Known only as a fossil, the most recent one from 70 million years ago, until discovered living in the sea off the east coast of South Africa Dec. 22, 1938. The specimen was described by Marjorie Courtney-Latimer, who wrote about it to S.African ichthyologist J.L.B. Smith.
I stared and stared, at first in puzzlement. I did not know any fish of our own, or indeed of any seas like that; it looked more like a lizard. And then a bomb seemed to burst in my brain, and beyond that sketch and the paper of the letter, I was looking at a series of fishy creatures that flashed up as on a screen, fishes no longer here, fishes that had lived in dim past ages gone, and of which only fragmentary remains in rock are known. [J.L.B. Smith, "Old Fourlegs: The Story of the Coelacanth," 1956]
Any of various fishes of the order Coelacanthiformes, having lobed, fleshy fins. Coelacanths are crossopterygians, the ancient group of lobe-finned fishes that gave rise to land vertebrates. They were known only from Paleozoic and Mesozoic fossils until a living species (Latimeria chalumnae) was found in the Indian Ocean in 1938. At least one other (Malania anjouanae) has been discovered since then.