Most, if not all, of us have asked the question: what if dinosaurs were still alive? Well, while a coelacanth isn’t exactly a dinosaur, it is one of the longest-living species known on Earth.

Coelacanths were first discovered by Louis Agassiz when he identified a 260-million-year-old fossilized tail in 1836. Coelacanths were assumed to have gone extinct roughly 409 – 66 million years ago. Within that time frame, these fish were found almost all over the globe in both fresh and saltwater until the end of the Late Cretaceous period.

All of this changed on December 22, 1938, when Marjorie Courtenay-Latimer, curator of the East London Museum, strange discovery in South Africa. She found what was thought to be a living coelacanth caught in a trawling net. It was recorded at 1.5 meters long, with vivid blue armor-like scales and strangely shaped fins.

These fish are one of the only remaining lobe-finned fishes on Earth, besides the hagfish. Lobe fins are fleshy, limb-like fins, which are supported by bone. This holds extreme evolutionary significance, as lobe-finned fish are believed to be a transitioning group toward Reptilia and the Tetrapoda phylum. Furthermore, coelacanths have a unique intracranial joint in their skull which allows for head tilt to increase overall jaw size for capturing prey, further proving their eventual connection to tetrapods.

This population in Africa was believed to be the last remaining habitat for these creatures. However, in 1998, a new subset population was found in Sulawesi, Indonesia, which marks the second and last known population on earth.

These coelacanth populations have been classified by NOAA as ranging from threatened to critically endangered. This comes from human effects on their habitat through means such as deep-water dredging and drilling, submarine blasting, and pollution, as they live in deep-water caverns. They also received this labeling not only from being classified as a Lazarus taxon, a species which disappears from the fossil record and then reappears millions of years later, but also due to their life cycles.

Coelacanths have one of the slowest maturation rates of any marine fish of their size. Males of the species reach maturity between 40 and 69 years old, while females take between 58 and 66 years. Furthermore, they live up to 100 years on average, with a 5-year gestation period—the longest of any vertebrate species.

These fish have witnessed some of the most ecologically significant events in our planet’s timeline. Not only does this truly show the resilience of life on our planet, but it also raises an even more profound question: what else is swimming in our waters, just waiting to be discovered?

Cover Image: Coelacanth (Latimeria chalumnae) off the coast of Pumula on the KwaZulu-Natal South Coast in South Africa. Photograph by Bruce A.S. Henderson. Source: Wikimedia Commons. Licensed under (CC BY 4.0).