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Submit an article to Indago - a peer reviewed journal
Submit an article to Indago - a peer reviewed journal
Submit an article to Indago - a peer reviewed journal
Author

Jan Andries Neethling

Browsing

Travelling through Brazil you find yourself in the Cerrado, a vast tropical savannah just southeast of the Amazon rainforest. Stopping under one of the trees, you sit down for a quick rest and to take in the natural beauty around you. Your eye then caches the movement of a fly landing on the rough bark of the tree and, ever ready as you are, you reach for your camera and inch closer to try and take a good macro photo.

The tail and sting of a South African burrowing scorpion (Scorpionidae: Opistophthalmus sp.) © Jan A. Neethling 2012

Scorpions have been around for more than 420 million years. Originally aquatic, they were some of the first creatures to venture onto land and have since taken up a completely terrestrial lifestyle. They occur on every continent except Antarctica, and are most prevalent in arid regions, though many species do occur in the tropics. They are amongst the most recognizable arachnids and are characterized by an elongate body, pincer-like grasping appendages (called pedipalps), four pairs of walking legs and a tail that terminates in a sting (telson).

Image: Fossil of Eurypterus remipes, a sea scorpion that lived 420 million years ago. © Millard H. Sharp 2017

How far back can you trace your family tree? A couple of generations to maybe a couple of hundred years? How about 460 million years? Because that is when the granddaddy of arachnids swam in the earth’s oceans, making the arachnid family tree truly ancient. And with more than 100 000 identified species living today, their family tree is not only ancient, but gigantic.

Pre-Devonian in origin, the Pseudoscorpiones are one of the oldest extant lineages and over the past 392 Ma have diverged into more than 3400 known species in 26 families. Most are less than five millimetres in length, though they range from less than one millimetre in some Chthoniidae to just over ten millimetres in females of Garypus titanius Beier, 1961. They superficially resemble true scorpions, but lack the elongated tail and sting.