Introduction to the Scorpiones Scorpiones Scorpions are the oldest arachnids for which fossils are known, and they were the first arachnid fossils to be found in Paleozoic strata. These earliest scorpiones are considered to be Protoscorpions, since they possess many traits which are plesiomorphic for scorpions. For example, in all scorpions the thick front portion on the abdomen is made up of seven segments, but the number of sternite plates which cover this region varies among the earliest fossils, while all living species have five.
All scorpions have an additional five segments after the initial seven, ending in a sharp sting.
This sting contains a pair of poison glands which can paralyze prey, usually insects or small rodents , or may deliver a painful sting to incautious persons. Most scorpion stings are merely painful, leading to swelling in the immediate region of the sting, but some scorpions of northern Africa and the American southwest can be deadly. Besides their unusually long and dangerous tails, scorpions also differ from other arachnids in having large pedipalps . These are the second pair of appendages on the body, and are usually rather inconspicuous in arachnids, but in scorpions, they are large and powerful pincers which may be used to grasp and subdue prey. Scorpions may also have more eyes than other arachnids, some species possessing as many as six pairs, though most do not have this many.