The coelacanth is a rare species of fish that was once believed to be extinct. Fossils of this ancient fish date back more than 400 million years, and scientists long assumed that it had disappeared along with many prehistoric species. However, in 1938, a living coelacanth was unexpectedly discovered off the coast of South Africa, astonishing the scientific community. This event is often described as one of the most significant zoological discoveries of the twentieth century.
Coelacanths possess several unusual anatomical features. Unlike most modern fish, they have lobed fins that resemble primitive limbs, which has led researchers to study them for insights into the evolution of land animals. In addition, they have a unique joint in their skull that allows them to open their mouths unusually wide, enabling them to capture larger prey.
These fish typically inhabit deep ocean environments, often at depths of several hundred meters, making them difficult to observe. Their slow metabolism and long lifespan—estimated at up to 60 years—suggest an adaptation to stable, low-energy ecosystems. Because of their rarity and ecological significance, coelacanths are now protected, and ongoing research aims to better understand their biology and evolutionary importance.
本文介紹腔棘魚（coelacanth）這一曾被認為已滅絕的古老魚類。雖然其化石可追溯至四億多年前，科學界長期認定其已消失，但1938年在南非外海意外發現活體個體，震驚學界，並成為二十世紀重要的動物學發現之一。
腔棘魚具有多項獨特的生理特徵，例如類似原始四肢的肉質鰭，使其成為研究陸生動物演化的重要線索；此外，其頭骨具有特殊關節，能使嘴巴大幅張開以捕捉較大型獵物。
此魚多棲息於數百公尺深的海域，觀察困難。其新陳代謝緩慢、壽命可達約六十年，顯示其適應於穩定且低能量的生態環境。由於其稀有性與生態價值，腔棘魚目前受到保護，相關研究亦持續進行，以深入理解其生物特性與演化意義。