Imagine walking through a silent forest and encountering a giant prehistoric creature, such as a dragonfly with a wingspan of 70 centimeters. Then imagine seeing the world's largest land invertebrate: a giant millipede 1.8 meters long. During the Pennsylvania period, this giant bug roamed North America, the largest being known as the Ancient Centipede (Arthropleura), which was the king of the millipedes in the forest. It has a staggering 0.46 meters wide and nearly 2.2 meters long. The largest fossil millipede found to date, including the footprints of the creature, proves that arthropods dominated the swamp forests of North America 300 million years ago.
Like the megalodon, a prehistoric shark about 18.3 meters long, the arthropods were much larger than their offspring, the millipede today. Before the advent of the dinosaurs, arthropods ruled the planet along with many other prehistoric creatures.
It is the largest terrestrial invertebrate in history
The giant ancient centipede flourished around 320 million to 290 million years ago, while laying the foundation for abundant coal reserves in North America and Europe. Although other aquatic arthropods outnumbered arthropods in size, no one on land could match them.
But how big are the ancient centipedes? Scientists believe it is generally more than 1.83 meters long and 0.46 meters wide. So it's a creepy creature, the king of the forest in the reptile kingdom.
It has no known predators
It's hard to imagine millipedes being at the top of the food chain, but ancient centipedes really had no known predators. Scientists have determined this fact by looking at the carapace of this creature. Researchers Otto Klaus, a millipede expert and Carsten Brackman, an expert on prehistoric arthropods, discovered the surprising fact that the carapace itself is quite thin.
With a surface only a few millimeters thick, unlike the exoskeletons of modern crustaceans, it does not contain a hard calcium carbonate component. So this evidence suggests that the ancient centipede had few or no enemies at the time who wanted to try to catch and eat it.
It is 1.83 meters long
How big is the Ancient Centipede? If a medium-height man lay in a Carboniferous swamp, an adult joint ancient centipede could completely cover his body. And scholars believe that ancient centipedes were at least two meters long.
However, they still haven't found a complete fossil from this creature, so it's possible that prehistoric millipedes will be larger.
It used to hunt in the forests of the United States
Where did prehistoric millipedes live? About 300 million years ago, many people referred to what is now the United States as the home of prehistoric millipedes. This is the story scientists found in the fossil record, as prehistoric millipede fossils were found in Kentucky and New Mexico.
One researcher described the traces left by the giant millipede in New Mexico as tire marks similar to those of a vehicle.
It may be a top predator
In addition to the absence of a known predator, the ancient centipede may have been a predator in its own right. In The March to Land, author Tom Holmes delved into what prehistoric millipedes ate. While scientists believe that the ancient centipede may have fed on rotting organic matter collected from large areas of forested moist ground, it may also have preferred to eat meat.
In addition to eating insects, scientists speculate that it may even prey on small vertebrates that are unfortunate enough to encounter this giant creature.
Scientists aren't sure exactly what it eats
Fossil remains of prehistoric millipedes reveal their size, shape, and way of life. But according to the fossil record, one thing scientists can't determine: what ancient centipedes actually ate for their livelihood.
Scientists still haven't found the mouth of the ancient centipede, which makes it difficult to determine what the creature ate. It may be a herbivore, and like many modern millipedes, it may also be a carnivore. Judging from the ancient fossils of centipede feces, it looks like plant-eating creatures, including ferns.
Its footprint shows its huge growth process
During fossil excavations, scientists sometimes find fossil footprints of ancient creatures, and ancient centipedes are no exception. In 2001, Michael C. Rygel photographed the huge footprints of millipedes found in southeastern Canada, Nova Scotia.
These footprints not only reveal the size of the millipede, but also provide some clues about the habitat of this creature. Some prehistoric footprints show ancient centipedes wandering around the trees in the forests where it flourished.
It lives in the coal swamps of North America
During the Carboniferous Period, arthropods dominated during the "coal swamp" period. About 300 million years ago, much of Europe and North America was covered by dense forests. These then decayed into peat in the wetlands and eventually turned into coal.
On the ground of the wetland forest, arthropods roam around, dominating as the largest invertebrates on land.
It may have gone extinct due to climate change
The ancient centipede is the largest terrestrial invertebrate ever built. But it eventually went extinct, possibly due to climate change. Prehistoric millipedes flourished in Pennsylvania due to high concentrations of oxygen and humid conditions. But the climate changed significantly about 290 million years ago, in the early Permian.
The earth is getting drier and drier, making it difficult for ancient centipedes to survive. Scientists say that the modern close relatives of ancient centipedes are modern centipedes. Thankfully, none of them are now more than 1.83 meters long.
It shares many characteristics with modern millipedes
Although it was much longer than today's millipedes, arthropods still share some common features with their offspring. First, it maintains the same body segment in proportion to the pair of legs. This creature has about 30 segments and about 40 legs. Like most modern millipedes, the ancient centipede is far from the thousands of legs its name suggests.
The prehistoric millipede had a flattened shape, with plates on both sides of the body extending to the length of the body and protecting the legs. These carapaces often decompose after death, making it a challenge to rely on the fossil record to reconstruct the full picture of this creature.
All the bugs were relatively large at the time
Yes, yes, the bugs used to be very large. In the time of the ancient centipede, it was just one of many giant insects and arthropods. Take, for example, the giant-veined dragonfly, a prehistoric insect whose pedigree can be traced back to today's dragonfly. At its largest, one of the variants can have a wingspan of more than 61 centimeters, making it one of the largest known insects.
But why did the ancestors of creatures like millipedes and dragonflies grow so big? Because Earth's atmosphere was very different in the past than it is now. In the heyday of giant insects, when the earth was warmer, wetter, and oxygen concentrations were higher, it meant it became the perfect breeding ground for giant insects.
The giant millipede is unlikely to return
Scientists believe that one reason ancient centipedes grew so large was because oxygen concentrations in the atmosphere were higher about 300 million years ago. But physics means that giant millipedes, larger than arthropods, are unlikely to wreak havoc on Earth.
Vertebrate paleontologist Hans Suez explains that as an arthropod, millipedes are limited in size. The creature's exoskeleton means that an arthropod much larger than an ancient centipede would not be able to walk normally because it would require stronger legs. And large arthropods also have difficulty transmitting oxygen throughout the body, so this may be one of the reasons why ancient centipedes disappear when oxygen levels drop.
Scientists are still looking for intact fossils
Ever since the ancient centipede was named in 1854, scientists have been looking for complete large fossils of the creature. In Germany, they found a partial fossil that was only about 0.91 meters long. In Nova Scotia, scholars have found footprints that may have come from ancient centipedes, meaning the creature is more than 1.5 meters long.
These traces are not the only clues to infer the size of ancient centipedes. The fossil record from the giant armor suggests that it may have exceeded 1.83 meters in length. So if scientists can find complete fossils of this creature, they may learn more.
Scientists still have a lot of questions about this
Although scientists first discovered ancient centipedes in 1854, there are still many questions about prehistoric millipedes. For example, scientists know very little about the life stages of the ancient centipede, including its larval stages. That's because only fossils with footprints and partial fragments have been found, and scientists still lack complete adult fossils. The exact structure of the creature's head also puzzled scientists, as the head and jaw areas remain incomplete in most fossils.
The best clue we found about this prehistoric creature came from its footprints, which have been found in many parts of Europe and North America. Dare not these footprints help determine the enormous size of the ancient centipede, but do not explain its other mysteries.