Eurypterids. I’m guessing you’re not familiar with that word, neither was I. Sea Scorpions are not something you’re likely familiar with either. Eurypterids are classified as Arthropods, which are spiders and lobsters and other creatures. The thing is that sea scorpions no longer exist and you should be darned happy about that.
These guys were floating around all water types, not just the seas but fresh and brackish waters also. 510 to 248 million years ago these sea scorpions were some of the most terrifying predators in the early oceans and waters. Most species could reach lengths of maybe 2 meters but most of the species were 20 cm or less. There were more than 300 species of sea scorpions over the millennia.
Recently scientists have found a claw from one of these creatures that is just scary. The claw is from a species called Jaekelopterus rhenaniae and is 18 inches long! This means that the sea scorpion that it came from had to be at least 8.5 feet long! Just imagine meeting that in a dark lake some night.
What this has shown those science types is that arthropods have grown a lot larger than previously thought. They knew that creepy crawlies like millipedes, scorpions, cockroaches, and dragonflies grew to a colossal size but this just gives them more information about the kinds of critters that grew to a giant size. Although this particular species was previously known to the scientific community they had no idea that they grew this large. They found this claw in German quarry and is about 390 million years old, give or take a year or two.
They assume that some of the smaller sea scorpions were able to get on land and shed their bony outer structures and eventually walk but the thought is that these big guys were simply not able to do that, simply because of their size.
These sea scorpions were cannibals but they basically ate whatever came their way and was smaller than themselves. Their claws were layered with teeth so that they could grasp even the slipperiest fish that might have crossed their paths.
The giant sizes of creatures such as dragonflies, some had a wingspan as large as seagulls, was due to an increase in oxygen levels in the atmosphere. But since sea scorpions were water dwelling so scientists doubt that atmospheric oxygen was a factor in their growth. Instead, it is thought that the absence of vertebrate predators allowed the sea scorpion to grow that large. After those other predators entered the scene they made lunch and dinner out of the larger sea scorpions.