Arthropods are a group of organisms that includes spiders, ticks, crabs and similar joint-legged invertebrates. Spiders, in particular, are well known because of their characteristic body plan and global distribution. From a cultural perspective, spiders are rather intimidating, and for obvious reasons.
Some, such as the Phoneutria (roughly translates to “Murderess” in Greek) can deliver a lethal bite.
Others, such as the tarantula have urticating hair which can embed themselves in the skin, causing great discomfort. Then, there are other spiders, which can reach truly terrifying proportions.
Present Day Giants
The Goliath birdeater is the heaviest spider in the world, often weighing as much as an adult human kidney (170 gms). It also has a leg span of about 11 inches, making it as long as a toddler’s forearm. It is endemic to the rainforests of Southern Venezuela and Northern Brazil.
It is an opportunistic predator, feeding on rodents, amphibians and large insects. The females have a lifespan of almost 25 years, but the males succumb soon after attaining maturity. The Goliath birdeater also has large fangs that carry venom but it is harmless for humans.
Astronomical Arthropods
300 million years ago, the earth was a very different place. It was lush, humid and the air had more oxygen than today’s levels. The oxygen cycle was essentially in overdrive, reaching peak oxygen levels before dwindling back down some 260 million years later. This environmental phenomenon had a significant impact on the flora and fauna which existed at the time – they grew to enormous sizes.
The largest arthropod to have ever lived is Jaekelopterus rhenaniae. At over 8 feet in length, Jaekelopterus was already much taller than an adult human. With powerful pincers near its jaws and long appendages ending in claws, it was the apex predator of its time. However, it lived in the oceans of the Early Devonian aeon. Hence, it was also known by another name – sea scorpions.
Back on land, the super-sized Arthropleura occupied the new niches created by the changing environment. It essentially resembled a modern-day millipede but was over 2.5 meters in length. It was a herbivorous arthropod, subsisting on the prehistoric flora. It grew to such large proportions due to the high oxygen levels in the atmosphere and the lack of predators.
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