The Coelacanth, also known as Latimeria chalumnae Smith, is a living fossil and the oldest known living lineage of Sarcopterygii, which includes lobe-finned fish and tetrapods. Nature continuously seeks out novelty, experimenting with different combinations and mutations to give rise to new and complex forms. While many living systems have evolved over time, some organisms have managed to survive relatively unchanged for hundreds of millions of years, demonstrating nature’s ability to create enduring designs.
Certain organisms seem to have struck gold early in the evolutionary process, maintaining their attributes through changing environments and cataclysms. Crocodiles, for example, first emerged around 95 million years ago during the Late Cretaceous period. These apex predators have perfected their hunting techniques over time, evolving from ancient ancestors like Deinosuchus.
Horseshoe crabs, despite their name, are more closely related to spiders and scorpions than true crustaceans. They first appeared during the Early Triassic era, approximately 250 million years ago, and have remained largely unchanged since then. Their slow rate of evolution has contributed to their survival through multiple extinction events.
The duck-billed platypus, a mammal that lays eggs, produces venom, and uses electroporation to detect prey, is a unique example of nature’s diversity. Believed to have originated during the Early Cretaceous period, the platypus showcases a remarkable blend of characteristics not typically seen in other mammals.
These ancient and resilient organisms serve as living reminders of the diversity and adaptability of life on Earth.
Egg-laying mammals known as monotremes have been able to survive since the time of the dinosaurs. The modern duck-billed platypus is a descendant of monotreme ancestors that lived approximately 120 million years ago during the Early Cretaceous period. Despite seeming unusual today, their ancient lineage has allowed them to outlast many other mammal groups.
Coelacanths, a type of fish, were believed to be extinct until they were discovered alive off the coast of South Africa in 1938. These creatures have been able to survive for an incredibly long time, remaining inconspicuous. Coelacanths belong to the subclass Actinistia within the class Sarcopterygii and possess lobe fins that serve as primitive limbs. Fossils of coelacanths that date back over 410 million years have been found. Previously, scientists thought they had gone extinct several hundred million years ago during the Late Cretaceous era. However, their rediscovery in 1938 revealed that they were still thriving. Despite evolving over time, modern coelacanths maintain striking similarities to their prehistoric ancestors due to their slow rate of evolution. While they are a rare species and not considered good for consumption due to their diet of fish, coelacanths continue to exist today.
The tuatara is often mistaken for a lizard or dinosaur but is, in fact, the last surviving species of the ancient reptile order known as Sphenodontia. This unique reptile order first appeared around 240 million years ago during the Triassic era. While tuataras were once widely distributed, they are now only found in the wild in New Zealand. Despite reservations about the term “living fossil,” tuataras exhibit many traits reminiscent of their dinosaur-era ancestors, such as two rows of teeth in the upper jaw, the ability to hear without external ears, and girdle-like structures in their skeletons. Remarkably, tuataras possess a genome of approximately 5 billion base pairs, which is about 67% larger than the human genome.
