Opinion Builds That Rare Fish Isn’t Evolutionary “Missing Link”

Source: Sentry Magazine, Vol. 15, No. 1, March 31, 1989

When the first living coelacanth came to the attention of scientists 50 years ago last month, they recognized it as belonging to a group of fishes previously known only from fossils and thought to have been extinct for 80 million years. The specimen, hooked by a fisherman, was quickly hailed as a "living fossil.”

The coelacanth (pronounced see-la-kanth) had long been thought to represent an evolutionary transition from fishes to the first land animals. The newly caught coelacanth’s fleshy fins, hinting at a resemblance to legs, helped earn it the label of “missing link.”

Today, however, there is a growing consensus among evolutionary biologists who have studied living specimens that coelacanths are not missing links. According to a report last week in the British journal Nature by Peter L. Forey of the British Museum (Natural History), the coelacanth features putatively linking it to land animals are probably only coincidentally similar.

For one thing, fossil coelacanths were thought to have lungs, like several species of lungfish living today. These air-breathing lungs allow lungfish to live out of the water for long periods. The structure, thought to have been the precursor of lungs in early amphibians, evolved into the swim bladder of the more advanced fishes. Living coelacanths turned out to have no lungs.

Still, interest in the three-foot-long, blue-and-white coelacanths remains high, especially among subsistence fishermen in the Comores Archipelago between Africa and Madagascar. Since the first specimen was recorded in 1938, at least 200 have been caught, and the pace of killing has increased rapidly in recent years.

Forey said that although no one knows how many coelacanths are in the ocean, they are rare, and a Coelacanth Conservation Council has been formed to protect the species against overfishing that could lead to its extinction.