This Megarachne, also called the Mesothelae Spider, is the size of a humans head. She'd be hunting cats if she were alive today.
— Allen, about Mesothelae

Megarachne (name meaning "Great Spider"), often called the Mesothelae spider, is a genus of giant arachnid that originated during the Early Carboniferous era in what is now North America. The size of a human head, this spider was able to hunt down animals as big as modern cats if it was alive today.

In the episode "Arthropods Swamp", a single female Megarachne, named Charlotte, was brought back from Carboniferous 300 million years ago. She resides in the Bug Dome exhibit.


Era & DiscoveryEdit

Megarachne lived during the Carboniferous period, about 350-280 million years ago and was among the apex predators of its time. Mesothelae was originally described in 1980 by the Argentinean paleontologist Mario Hünicken.

Physical AttributesEdit

Megarachne was very large compared to modern spiders with large fangs. Their bodies alone, minus their legs, were the size of a human head, making them the largest spiders that ever existed. It had black skin with the chelicerae being red.

Behavior & TraitsEdit

A Walking with Monsters - Life Before Dinosaurs PDVD 011

Like most modern spiders, Megarachne was an ambush predator, operating from their underground headquarters. When safe inside their whole, they rested their legs on carefully constructed trip lines that allowed them to pick up vibrations from outside. However, unlike modern spiders, Megarachne didn't make the iconic orb-web but rather would hide in burrows in the ground and use its silk to create trip lines that would pick up vibrations from outside their holes.

If prey was detected, it would ambush its victim and when the spider killed its target it would take its victim back to its burrow where the spider would inject its digestive juices into the killed prey. Once they had, caught, and killed their prey, Megarachnes took their food back to their layer and injected them with digestive juices to dissolve them from the inside.

However, living in burrows always had its risks because it could easily be destroyed by a flood because of the rising waters of the Carboniferous. Once that happened, assuming they survived the flood, Megarachne had to leave their home. Unlike the modern-day trapdoor spiders, Megarachne wasn't capable of digging holes. Therefore, they were unable to create their own home, so they would have to wander out into the open and search for another burrow. Megarachne did not like to share their home with others of their kind, leaving a wandering giant spider vulnerable to the larger predators of the Carboniferous.


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