Coelacanth – A Relic From the Past

Introduction

Dinosaurs roamed the earth for more than 135 million years, eventually becoming extinct 66 million years ago. Along with dinosaurs, a multitude of other life forms also became extinct – the Coelacanth being one among them. However, the animal was seen again for the first time in 66 million years, when it was found among the catch of a local fisherman off the coast of Africa in 1938.

Description

The Coelacanth is more closely related to the lungfish – another intriguing relic from the past. Its respiratory system comprises gills and a fat-filled vestigial lung. The fish is also rather large, typically growing over 6.6 feet in length and weighing over 90 kilograms. The fish has very large eyes, which are acclimatized to environments with low light and visibility. Hence, coelacanths are primarily nocturnal animals. The animal is a piscivore, meaning that it feeds on other fish. It also has thick scales that function as armour. The animal has eight fins – two dorsal fins, two pelvic fins, two pectoral fins, one caudal fin and one anal fin. Interestingly, the Coelacanth’s braincase is filled with 98.5% fat- just 1.5% of the case contains brain tissue. Moreover, fish has two kidneys, but they are fused into one structure, which is located within the abdominal cavity.

Significance

The Coelacanth is of special interest to biologists as the species represents one of the best examples of the Lazarus taxon. A Lazarus taxon, in its most basic sense, can be understood as organisms that were not seen for millions of years. Such organisms are called “living fossils” as they have not changed from their fossil counterparts millions of years ago. This phenomenon has been observed quite a few times in the earth’s history where organisms would become extinct, only to reappear in fossil records at a much later date.

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