Selects: How Coelacanths Work

The history of the coelacanth, a fish long believed to have been extinct, took an astonishing turn when it was rediscovered off the coast of South Africa in 1938.

Coelacanth Discovery in 1938 Off South Africa Coast

In the 1930s, the coelacanth—a fish thought to have vanished alongside dinosaurs—reappeared, shocking the scientific community with its continued existence in the oceans.

Coelacanth Discovered by Marjorie Courtney-Latimer Recognizing Extinct Fish

Marjorie Courtney-Latimer, the director of the local museum in East London, South Africa, discovered an unusual fish among a trawler’s catch during a pre-Christmas inspection. The fish, a 127-pound specimen with a unique pale mauve blue color, hard scales, and four limb-like fins, was something she had never seen before. Despite the heat and the approaching holiday, Latimer made the decision to bring the fish to the museum for further examination.

Coelacanth Discovery Stuns Science As "Missing Link"

The fish was later identified by Courtney-Latimer as a coelacanth, a species presumed extinct and known previously only from fossils. J.L.B Smith, upon receiving a sketch of the fish from Courtney-Latimer, recognized its significance despite the mounting process that could have obscured its key features. This monumental discovery was soon recognized as the zoological find of the century, leading to th ...

Chuck Bryant discusses the intriguing physical characteristics and reproductive strategies of coelacanths, large deep-sea fish known for their unique biology.

Coelacanths Are Large Fish With Unique Physical Characteristics

Coelacanths are recognized for their considerable size and distinctive traits that set them apart from other marine species.

Coelacanths Have an Oil-filled Spine and a Hinged Jaw

Coelacanths reside primarily in the ocean's twilight zone, commonly between 500 to 800 feet deep, but they can live as deep as 2,000 feet. These nocturnal hunters have several unique features, including a notochord, which is a hollow, pressurized tube filled with oil, and an unusual hinged cranial element that allows them to open their mouths very wide by retracting the top part of their skull. This adaptation is advantageous for their predatory lifestyle, enabling them to consume more significant prey.

Coelacanth Fins: Precursors to Tetrapod Limbs, now Serve Different Locomotion Purpose

Although no direct input refers to coelacanth fins as precursors to tetrapod limbs, it is a widely recognized scientific fact that coelacanth fins are structured in a way that resembles the limb bones of terrestrial vertebrates, indicating their importance in the understanding of the evolutionary transition from aquatic to land environments.

Coelacanths Use an Organ to Detect Prey's Electrical Signals

Bryant notes that coelacanths possess a specialized rostral organ within the nasal region of their snout, capable of detecting the low-level electrical signals emitted by their prey. This organ is crucial for hunting in the dee ...

The coelacanth's evolutionary history is under scrutiny as recent genome analysis provides new insights into its relationship to other vertebrates.

Coelacanth's Evolution Is More Complex Than Thought

Recent genetic analysis shifts our understanding of the coelacanth's place in the evolutionary tree.

Genetic Analysis: Coelacanth More Closely Related to Lungfish Than Tetrapods, All Sharing a Sarcopterygian Ancestor

Researchers have found that while we're all sarcopterygians—vertebrates with lobed, fleshy fins or limbs—the coelacanth is not the direct ancestor of terrestrial vertebrates as was once believed. Rather, genomic analysis shows that the coelacanth is more closely related to the lungfish than to tetrapods, with all groups sharing a sarcopterygian ancestor.

Coelacanth Genome Reveals Significant Evolution, Challenging "Living Fossil" Concept

Josh Clark argues that coelacanths, often labeled as "living fossils," have undergone significant changes, evidenced by differences in size when compared to their ancient counterparts. The coelacanth's full genome, which was studied and published in Nature, demonstrates slower evolution with a lower rate of genetic substitution than seen in other species, challenging the concept that coelacanths have remained unchanged through time.

Coelacanths Diverged From Sarcopterygians Millions Of Years ago, Forming an Ancient Vertebrate Bra ...

The enigmatic coelacanth, a rare and ancient type of fish once thought to be extinct, is facing modern-day challenges that warrant its listing as an endangered species.

Endangered Coelacanths Need Protection

Two Extant Coelacanth Species, one Off Africa and Another in Indonesia, Have Populations Ranging From Hundreds to Low Thousands

Coelacanths, often known as "living fossils," are split into two known extant species. Clark points out that the West Indian Ocean Coelacanth, commonly found around the Comoros Islands off the east coast of Africa, and its cousin in Indonesian waters both have dwindling populations. Estimates suggest there could be around a thousand individuals in the Indonesian region, with far fewer off the coast of Africa.

Coelacanths Threatened by Bycatch and Habitat Loss, Risking Population Decline

These ancient creatures, which have survived for millions of years, are now threatened primarily by human activities such as bycatch and habitat loss. While some coelacanths find refuge in deep-sea cave dwellings where they have some protection, those off Tasmania are particular ...