The coelacanth, a 400-million-year-old fish, represents an impasse for the theory of evolution. This fish has not undergone any changes in 400 million years. The fact that it has preserved its earliest physiological structures over this length of time—despite continental shifts, climate changes and changes in environmental conditions—baffles evolutionists. The coelacanth once again invalidates the theory that living things evolved and that they undergo a constant process of evolution. The coelacanth fossil seen here is in two sections. In this type of fossil, mirror-image traces of the creature appear on the two split halves of the stone. The coelacanth is a large fish, about 150 centimeters (5 feet) in length, its body covered with thick scales that resemble armor. It belongs to the boned fish classification Osteichthyes, and the first fossil specimens were discovered in strata belonging to the Devonian Period. Until 1938, many evolutionists imagined that this fish used its two pairs of fins to walk on the sea bottom and that it was an intermediate form between marine and terrestrial animals. To support their claim, evolutionists pointed to the bony structure of the fins evident in the coelacanth fossils they had obtained. However, a development in 1938 completely disproved the claims regarding intermediate species, when a living coelacanth was caught off the coast of South Africa. This creature had been thought to have become extinct at least 70 million years ago. Research showed that the coelacanth had undergone no change in 400 million years.