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

Megarachne (name meaning "Great Spider"), often called the Mesothelae spider, is a genus of giant arachnid that originated during the Late Carboniferous era in what is now North America. As large as a human head, this spider, the largest ever discovered, would have been able to hunt down animals the size of domestic cats had it survived through to the 21st century.

In the Series 1 episode "Arthropods of the Swamp," a single female Megarachne, named Charlotte, was brought back from Carboniferous North America, 300 million years ago. She resides in the Bug Dome exhibit. Unknown to the team that other Megarachne had also followed the team through the time portal and now resides in the Bug Dome with Charlotte.

Facts[edit | edit source]

Era & Discovery[edit | edit source]

Megarachne lived in North America during the Carboniferous period, about 303 – 298 million years ago and was among the apex predators of its time. Megarachne was originally described in 1980 by the Argentinean paleontologist Mario Hünicken.

Physical Attributes[edit | edit source]

With a body length of a little over a foot long, Megarachne was a very large spider with large fangs. Their bodies alone, minus the legs, were the size of a human head, making Megarachne the largest species of spider that has ever existed. It had black skin with the chelicerae being red.

Behavior & Traits[edit | edit source]

A Walking with Monsters - Life Before Dinosaurs PDVD 011.jpg

Like most modern spiders, Megarachne was an ambush predator, operating from their underground headquarters. When safe inside their hole, 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, Megarachne would ambush its victim and chase it until it was killed. When the spider caught and killed its target prey, such as a Petrolacosaurus, Megarachne would take its victim back to its burrow where the spider would inject its digestive juices into the killed prey and 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 was incapable of digging holes. Therefore, they were unable to create their own homes, so they would have to wander out into the open and search for another burrow. Megarachne did not like to share their home even with others of their kind, leaving a wandering giant spider vulnerable to the larger predators of the Carboniferous.

Gallery[edit | edit source]

Trivia[edit | edit source]

  • Megarachne was the first and the largest prehistoric spider to be brought to the park. The next one was Protosolpuga.
  • Despite being a spider, the series portrays Megarachne with the capability of producing clicking and screeching noises by using its mandibles.
  • Despite the creature's name meaning "great spider," Megarachne is now thought to have been a species of sea scorpion.
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