Coelacanth, meaning 'hollow spine' in Greek, (coelia hollow meaning and acanthos spine) is the common name for an order of fish that includes the oldest living lineage of gnathostomata currently known to science. The coelacanths are related to lungfishes and tetrapods. They were once believed to have been extinct since the end of the Cretaceous period up until the first Latimeria specimen was found off the east coast of South Africa off the Chalumna River in 1938. Because of this they are often labeled as living fossils, or a Lazarus taxon. Since 1938, Latimeria have been found in many other habitats, including Madagascar, the Comoros, Kenya, Tanzania, Mozambique, and the Saint. Lucia Wetland Park in South Africa. The second species Latimeria, Latimeria menadoensis, was described from the Sulawesi of Indonesia in 1999. Read on . .

The Coelacanth, Caridosuctor populosum ( Osteichthyes, Sarcopterygii, Coelacanthiformes) is well-represented in the Bear Gulch limestone Laggerstatte of Montana, where they are often found with exquisite preservation.