The Coelacanth: Five Fast Facts

by AMNH on

From the Collections posts

Once thought to be long-extinct, coelacanths have a number of unique features that make them particularly interesting to researchers. The Museum’s first specimen, which answered one pressing question about these fish, arrived in 1962. Watch this episode of Shelf Life to learn more.

Detail of coelacanth, emphasis on head and teeth.
Coelacanths have been widely studied since their discovery in 1938. 
Courtesy of Phil Dragasg/Wikimedia

To get you up to speed on the subject, here just a few notable points about this fascinating animal.

  1. When the first modern coelacanth was discovered in 1938 off the coast of South Africa, scientists were amazed: this group of fish had been long thought to have gone extinct at the end of the Cretaceous period, some 70 million years ago.
  2. There are two living species of coelacanth, the West Indian Ocean coelacanth and the Indonesian coelacanth. These fish live in deep saltwater environments and can grow to be nearly 2 meters long. Paleontologists know the order was once much more diverse, though, and included massive species that dwelled in ancient freshwater lakes and were up to 5 meters long.
  3. Like sharks, coelacanths give birth to live young, a rarity in fish. This wasn’t known until the Museum’s first coelacanth specimen was dissected in 1975-- and found to be pregnant with five embryos.
  4. Coelacanths were once thought to be a possible “missing link” between fish and early land-dwelling tetrapods. Though they are related to coelacanths, studies have shown that lungfish is tetrapods’ closest ancestor.
  5. Coelacanths have an organ filled with a jelly-like substance near the front of their heads, a feature found in no other vertebrate. Researchers think this “rostral organ” plays a role in coelacanth hunting, detecting low-frequency electrical signals given off by prey.