|“||That is Arthropleura. He's a distant relative of modern Millipedes and Centipedes, but as long as a car. He can rear up tall enough to look you right in the eye.||„|
|— Allen, about Arthropleura|
in Arthropods of the Swamp
Arthropleura (name meaning "Rib Joint") is a genus of millipede arthropod that originated during the Late Carboniferous period in what is now North America and Europe. A distant relative of modern millipedes and centipedes measuring 3 meters long, it was the largest known of all the terrestrial arthropods as well as the largest land invertebrate of all time and grew so large because of the high concentration of oxygen level in the Carboniferous's atmosphere. Despite its large size, Arthropleura was herbivorous, in fact, one of the first mainly herbivorous terrestrial animals. They had strong jaws, but it is unlikely that it may have been poisonous for defense.
In the Series 1 episode "Arthropods of the Swamp," several Arthropleura, along with a large 20-foot individual named Arthur that had followed the team through the time portal, were brought back to the park from Late Carboniferous North America and Europe, 300 million years ago. The group now resides in the Bug Dome enclosure. However, Arthur resides in his own enclosure due to his immense size.
Era & Discovery
Arthropleura lived in North America and Scotland during the Late Carboniferous, approximately 315 – 299 million years ago. It lived alongside other animals like Megarachne, Pulmonoscorpius, Meganeura, and even the primitive reptiles and giant predatory amphibians. Since their discovery in 1854, there are many fossilized footprints from Arthropleura can be found on the coast of Scotland in the Scottish land of Arron.
Arthropluera was perhaps the largest arthropod of the Carboniferous and was overall among the largest arthropods that ever lived, measuring on average between 6.6 – 10 feet (2 – 3 m) long, as large as a man or crocodile and as long as a car. However, there were very rare colossal specimens that were discovered to have measured around 20 feet (6 m) in length. Arthropleura is the largest land arthropod known, a huge relative of the modern millipedes closely resembling a giant centipede or millipede.
The reason why they were able to grow so large is that oxygen levels were 50% higher than today. The higher oxygen level content in the atmosphere of the Carboniferous could support larger species whose circulatory system was not as efficient as those of mammals and other species. Therefore, it allowed this creature (and many others) to grow to very large sizes. In addition, males and females were different in appearance. Arthropluera was arguably the largest known land invertebrate of all time and would have had few predators (If any as an adult.)
Arthropleura was heavily defended by thick, tough, and wide armor plating along its back. Underneath its armor were lots of small legs and a soft underbelly. On its head, it had two pincers and two antennae. The color of Arthropleura varied. Some of them were red with yellow lines whilst some were brown with yellow lines. The body of the Arthopleura was composed of thirty armored plates, which each had a pair of legs under them. However, it was not invincible as large amphibians, like Proterogyrinus, could relatively easily get the better of it. Even its own environment could threaten it. Sharp rocks could easily impale Arthropleura and the superpowered Carboniferous storms were often devastating to Arthropleura as well as other animals.
Behavior & Traits
Arthropleura was a solitary creature, often foraging on the forest floors of the Carboniferous. Arthropleura was a massive arthropod that they were such powerful beasts. In spite of its daunting appearance, it as a herbivore, feeding on the rotting foliage, dead-wood and leaves on the floor of the steamy Carboniferous Period swamp forests. Although later found out they were vegetarians, their strong jaws can still have delivered a nasty bite.
Arthropleura was herbivorous though when they were juveniles, they ate meat because they couldn't digest plants until they grew older. Arthropleura was one of the first animals to eat plants, they had strong jaws, but it is unlikely that it may have been poisonous for defense. Arthropleura was practically blind but had a good sense of smell and touch through which to detect other animals. It is discovered that while Arthropleura was a timid creature, it was also shown to be highly aggressive and could be easily provoked into attacking.
Most Arthropleura lived in piles of leaves or foliage or in small underground dens whilst some lived out in the open. As its body armor was colored similar to its surroundings, Arthropleura was camouflaged. However, its armor couldn't protect it from the Carboniferous forest fires. Although the animal would often crouch for cover on the ground, most of the time it was burned alive.
When it comes to fighting, their armor was their best defense unless it got split. Much like cobras, Arthropleura could rear up at its opponent so it could tower over it, tall enough to look humans right in the eye. And that rearing up was obviously a defensive reaction. However, rearing up would expose its soft innards and were a bulls-eye for predators. They could spray like modern millipedes and centipedes. They could secrete cyanide. That smells of almonds and when they spray in the eyes of their enemies, and it really burned. Uniquely, Arthropleura was also able to leap long distances, which allowed it to strike at its prey like a battering ram.
Additionally, Arthropleura possessed a deadly venom, injected into a victim through a long, thin, metallic-looking tube located behind its mandibles, in a similar manner to an insect bite. When a large mammal such as a human was poisoned by an Arthropleura, the venom would slowly attack their central nervous system, putting the bitten victim into a state of uncontrollable shaking and convulsion very shortly after being bitten, and rendering them barely able to move, before they lost consciousness after a while. An antivenin could be derived from pure samples of Arthropleura venom, but without this antidote, poisoned humans would have a zero chance of survival, dying a matter of hours after being bitten. If one did survive and recover from an Arthropleura's venomous bite, then they would still be left with short-term memory loss.
- Arthropleura was not believed to be venomous by any means, since it presumably had no enemies and ate dead plant matter.
- Despite being an insect, Arthropleura appears to make sounds of its own. It does make sounds when it moves its legs, but the sound it makes itself are screeches and hisses of some kind.
- Arthropleura was the largest and second prehistoric millipede to be brought back to the park.