How could the ancient giant scorpion Jaekelopterus rhenaniae breathe?

Question

I always thought arthropods could not get that big, because of their method of oxygen transport. They have no lungs. How could these 8-foot-long arthropods get enough oxygen to survive?

Answer 1

It was a marine creature, so it didn't 'breathe' as such - it had gills. Land invertebrates were able to grow much larger in the past than they can now due to there being a higher level of oxygen present in the atmosphere.