Remember when you were a kid and dinosaurs and giant prehistoric beasts were just the coolest (or they still are)? While T-rexes and velociraptors are not roaming the earth anymore, some of their descendants and neighbors are still here, the same as ever as living fossils. Living fossils are snapshots of beings of the past, often the survivors of many mass extinctions, these organisms can appear otherworldly and provide a ton of knowledge to scientists about the past and should be protected.
A fossil is preserved remains, impressions, or traces of ancient organisms kept in the earth’s crust. The word “fossil” itself comes from the Latin word “fossus,” meaning “dug up.” The term living fossil is used to describe organisms that have remained relatively unchanged for millions of years and have little to no close living relatives. When you take a fossil of that species from millions of years ago, the live version you see today is nearly identical. This makes them very valuable to scientists in understanding how ancient creatures may appeared, evolved, behaved and more.
The two big reasons living fossils stay mostly unchanged for so long is either because there is a small amount of diversity due to small populations and/or they fulfill their niche very well. Charles Darwin describes them for when competition has slowed to a crawl for them, so there is very little need to evolve. As they say, if it ain’t broke, don’t fix it.
Most examples of non-microscopic living fossils are under the sea. Two notable examples are the horseshoe crab and the Goblin shark. Starting with the horseshoe crab, it is not even a crab, but very distant relative of sea scorpions and sea spiders. They have remained mostly unchanged for at least 445 million years, well before any dinosaur. Their hard shell makes them incredibly endurant, and they play an important part in their coastal ecosystems with their eggs being snacks for many animals.
In the deep depths of the ocean, Goblin sharks are the only living representative of the family Mitsukurinidae, which dates to 125 million years old. Many describe it as very alien-like, its body is very flabby with low density. It has small fins for a shark, a snout covered in electro-recepting pores, and a protruding jaw that extends out to catch its prey covered in sharp, cactus-like teeth.
For an example above water, one is a bird called the hoatzin which appeared 36 million years ago. It is relatively young compared to the goblin shark and horseshoe crab, because all birds come from the few dinosaurs that survived the K-Pg extinction, the hoatzin being one of the first to branch out. They have no close relatives and their appearance shows it. Hoatzins are the only bird species that have retained claws on their wings as chicks, eat leaves instead of meat, seeds or fruit like most birds. The Hoatzin is one of the closest you could get to a pre-extinction dinosaur.
One living fossil that can be found here in Florida is the Gulf sturgeon. Gulf sturgeon are a subspecies of the Atlantic sturgeon that branched off from one another with the separation of the Florida peninsula from the Atlantic about 2 million years ago. Sturgeons have existed for at least 200 million years and they can live for over a hundred years and grow up to 20 feet long!
Gulf sturgeons are most found in the Suwannee River and the nearby Choctawhatchee River and as bottom feeders, they mostly eat creatures such as isopods, mollusks, crabs and marine worms. Despite their long life, sturgeon are one the most endangered fish in world, due to overfishing, poaching, pollution, and habitat destruction. They are harvested for their roe, internal fish eggs that is used in luxury dishes.
A lot of living fossils are facing endangerment after millions of years on earth due to human interaction. Good news is many governments and organizations work to protect species to keep them around for years to come. Gulf sturgeon, for example, are protected by Florida law, making it illegal to hurt or keep them. The Florida Fish and Wildlife Conservation urge people to be aware of them and pay attention to what you catch.
It is also important to mention that a lot of organisms that are or were considered living fossils are no longer classified as such due to new information. One of the most popular living fossil is the coelacanth, a cave-dwelling fish thought to have been extinct for millions of years, which was discovered alive in 1938.
Coelacanths are ancient, lobe-finned bony fish- fishes that evolved into all terrestrial vertebrates. The rediscovery provided a ton of information on how fish managed to transition onto land nearly 400 million years ago. However, it is debated if coelacanths can be considered living fossils, since after decades of study, scientists found a lot of differences between modern coelacanths and the fossil record of them. So while they are unique with no close relatives, they have changed a lot over many epochs. Fossils are commonly found incomplete with little to go off, so new discoveries are always being made.
All and all, living fossils are incredible survivors of the test of time and are topics of fascination for scientists and dinosaur fanatics. They have been around millions of years; let’s all keep these amazing creatures around for many more.
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