NOW YOU SEE ME...
Naturalist Georgina Jones sheds light on the enigmatic coelacanth.
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MOST TANTALISING FISH, the coelacanth. Popping up unexpectedly
in time and place, perplexing in reproduction, behaviourally enigmatic, a bony fish more closely related to mammals and reptiles than to other bony fish; coelacanths are fascinating. The ancient history of the coelacanth begins about 400 million years ago, with Miguashaia. The first coelacanth described by science, Coelacanthus, lived about 260 million years ago. Its name was derived from the hollow spines supporting the fish’s powerful tail fin. The line diversified in shape, size and habitat, exploiting all aquatic environments around the world. But by the time of the dinosaurs, it had dwindled to the most recent coelacanth fossil known, Swenzia, when, so far as anyone knew, they became extinct. 42 |
SEA RESCUE SUMMER 2021
They rose to prominence again in the great controversies surrounding evolution, being suggested as the possible ancestor of landdwelling vertebrates. Their eight powerful lobed fins and heavy spiny scales hinted at a possible link to the earliest land-dwelling vertebrates, a link that was later disproved as other, more likely, ancestors were discovered. The recent chapters in the coelacanth story began just before the start of World War II, offshore of the Chalumna River in the Eastern Cape. A trawl in 40-70m of water produced, along with the normal load of ‘edibles’ (hake, kingklip, seabream), a large deep blue fish with white markings and a huge lamp-like eye. It looked very different to the other fishes: as well as its size, it had an unusual number of fins and a very strange-looking tail.
