
Several species of tailless whipscorpions live in caves, like this Daemon variegatus from Mozambique. [Canon 7D, Canon 14mm, Canon MT-24EX twin light]

The first pair of legs of whipscorions resembles insect antennae in their length and function. Their surface is covered in bristles, trichobothria, and slit organs that detect the presence of and the distance from the prey. [Canon 1Ds MkII, Canon 16-35mm + extension ring, Canon MT-24EX twin light]
This really is unfortunate because these animals are fascinating. They belong to a lineage that goes back in time to at least the Carboniferous, and has remained relatively unchanged in their morphology. Only about 140 species are known, mostly from forests of warm and humid tropical areas within the tropics, and only a small handful have ventured into subtropical regions of Europe and North America (including one interesting species from Florida that is capable of staying submerged underwater for up to 8 hours.)

Heterophrynus sp. from Guyana has just sensed a cricket and is ready to pounce on it the moment the insect moves. This genus has some of the longest pedipalps among these arachnids. [Canon 5D, Canon 100mm, Canon MT-24EX twin light]

Two males of Costa Rican Phrynus parvulus engaged in a territorial battle. [Canon 10D, Canon 100mm, Canon MT-24EX twin light]
Young whipscorpions occasionally aggregate into small groups but adults, males in particular, are pretty cantankerous and territorial creatures. They will not tolerate another individual of the same sex in their vicinity, resulting in intense albeit largely ritualized battles.

Female whipscorpions are devoted mothers and carry their young until these are ready to begin independent life. [Canon 1D MkII, Canon 100mm, Canon 580EX speedlight]
Note: Other common common names are sometimes used for this group of arachnids, including tailless whip spiders and amplypygids. The name whipscorpions is often spelled as two words – whip scorpions – but I prefer to combine them into one to emphasize their distinction from true scorpions, members of the order Scorpiones. The same principle applies to insect names: scorpionflies, stoneflies, and butterflies are not flies, and this fact is indicated by combining the root “-fly” with the modifier into one word. Crane flies, on the other hand, are true flies.

Unlike insects and most arachnids, tailless whipscorpions continue to molt periodically even after reaching maturity. [Nikon D1x, Sigma 180mm, flash Nikon SB-28DX]

Cannibalism is not uncommon among tailless whipscorions, as demonstrated by this Phrynus sp. from the Dominican Republic. [Nikon D1x, Sigma 180mm, flash Nikon SB-28DX]

Members of the genus Charinus, like this C. pescotti from northern Queensland, have very short pedipalps. They apparently hunt by gently herding their prey towards the mouth with the antenniform first pair of legs, and only when the victim is very close, grab it with the pedipalps. [Canon 10D, Canon MP-E 65mm, Canon MT-24EX twin light]
A nice selection of species from around the globe. I’ve seen them in Arizona and Ecuador but haven’t had a chance to photograph them in the wild yet. I do have photos of a Tanzanian Diadema and the Floridian Phrynus that a friend has in culture, Simply spectacular animals!
Few groups trigger more common name arguments than this one – this one at Wikipedia being an especially humorous example.
Fantastic post. Charinus pescotti occurs relatively close to my place in NE Qld, but they seem to be a lowland species. Must be too cold for them up here on the Tablelands. I’ve searched for Charon trebax, the other Qld species, at type locality S of Townsville, but no luck. Plenty of snakes, though.
I worked as a boxboy at a supermarket in southern California 40 years ago- one day one of these came in (barely alive) with a fruit shipment. I kept the specimen for several years without really knowing what it was (except I knew it was not a spider). Nice post.
Fascinating details about an unusual ancient species – thank you for your post and photos!
When we lived in Tanzania, one of the facts of life was that Diademas liked to burrow into piles of laundry, presumably for warmth and shelter. You sort of expected one to emerge when you shook out the clothes, but it was always a bit of a shock because they move so darned fast.
Nice, educating and intresting to learn about those unusual species. Thanks for that.
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Beautiful pictures there, Piotr. I still do wonder what’s their defense mechanism when threatened, other than scuttling away(as you say).
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