O. P-Cambridge, 1872
|c. 15 genera, > 100 species|
Thelyphonida is an arachnid order comprising invertebrates commonly known as vinegaroons (or vinegarroons). They are often called uropygids in the scientific community after the former order Uropygi (which originally also included the order Schizomida). They are also known as whip scorpions because of their resemblance to true scorpions and because of their whiplike tails.
Physical description 
The name "uropygid" means "tail rump", from Greek οὐροπύγιον (ouropugion), from οὐρά (oura) "tail" and πυγή (puge) "rump" referring to the whip-like flagellum on the end of the pygidium, a small plate made up of the last three segments of the abdominal exoskeleton.
Whip scorpions range from 25 to 85 mm (0.98 to 3.3 in) in length, with most species having a body no longer than 30 mm (1.2 in); the largest species, of the genus Mastigoproctus, reaching 85 mm (3.3 in). Because of their legs, claws, and "whip", though, they can appear much larger.
Like the related orders Schizomida, Amblypygi, and Solifugae, the vinegarroons use only six legs for walking, having modified their first two legs to serve as antennae-like sensory organs. Many species also have very large scorpion-like pedipalps (pincers). They have one pair of eyes at the front of the cephalothorax and three on each side of the head, a pattern also found in scorpions. Vinegarroons have no venom glands, but they have glands near the rear of their abdomen that can spray a combination of acetic acid and octanoic acid when they are bothered. The acetic acid gives this spray a vinegar-like smell, giving rise to the common name vinegarroon.
Vinegarroons are carnivorous, nocturnal hunters feeding mostly on insects and millipedes, but sometimes on worms and slugs. Mastigoproctus sometimes preys on small vertebrates. The prey is crushed between special teeth on the inside of the trochanters (the second segment of the "legs") of the front appendages. They are valuable in controlling the population of roaches and crickets.
Males secrete a sperm sac, which is transferred to the female. Up to 35 eggs are laid in a burrow, within a mucous membrane that preserves moisture. Mothers stay with the eggs and do not eat. The white young that hatch from the eggs climb onto their mother's back and attach themselves there with special suckers. After the first molt, they look like miniature vinegarroons, and leave the burrow; the mother dies soon after. The young grow slowly, going through three molts in about three years before reaching adulthood. They live for up to another four years.
Vinegarroons are found in tropical and subtropical areas excluding Europe, Australia, and, except for an introduced species, Africa. They usually dig underground burrows with their pedipalps, to which they transport their prey. They may also burrow under logs, rotting wood, rocks, and other natural debris. They prefer humid, dark places and avoid light. They also live in the Southern and Southwestern United States.
Captive care 
When caring for vinegaroons it is important to create a habitat that is similar to its original environment. Young vinegaroons can be kept in small deli containers while larger vinegaroons should be housed in one to two gallon aquariums or terrariums. Containers made of plastic or glass are preferred because they prevent vinegaroons from climbing while also maintain humidity. Moisture is very important and a source of water should always be provided either by keeping a section of the substrate damp or by using a very shallow dish that is small enough to avoid drowning. Temperature should be kept between 70 to 80 degrees Fahrenheit to emulate tropic environment and only ten percent of the cover is needed for ventilation. The best substrates to use include coco fiber or non additive potting soils since they do not tend to stick to the exoskeleton. Using several inches of substrate allows vinegaroons to dig but heavy objects added to the habitat should be placed with care as to prevent cave-ins.
Prey that cannot climb the sides of containers, like Eublaberus or Blaberus burrowing cockroaches, are preferable when feeding vinegaroons. Crickets work well especially if legs are removed to prevent jumping. Young can be fed wingless fruit flies or pinhead crickets. Vinegaroons are very cooperative eaters and should be fed a few times a week but pregnant females with egg sacs should not be fed until young hatch, this ensures no damage is caused to the egg sac.
Health concerns 
Overfeeding can lead to a massive population growth of grain mites that while in the hypopus stage can cling to the body and block breathing channels. Moderate feeding and removal of leftover remains is recommended as a preventative measure. A ‘clean up crew’ of small isopods or springtails also helps to clean up debris as well as mold that may grow inside the cage. Vinegaroons should be handled with care and should not be held high above hard surfaces as to prevent accidental dropping. Their exoskeletons can crack easily and phorid flies or grain mites will attack wounded areas.
As of 2006, over 100 species of vinegarroons have been described worldwide. Subtaxa of vinegarroons currently include only one extant family and a doubtful extinct family:
- Hypoctoninae Pocock, 1899
- Mastigoproctinae Speijer, 1933
- Thelyphoninae Lucas, 1835
- Typopeltinae Rowland & Cooke, 1973
- Typopeltis Pocock, 1894
Rowland & Cooke (1973) provided a useful synopsis of the order, including a key to genera and a checklist of species. They also presented a novel classification that included the division of the group into two families, Thelyphonidae and Hypoctonidae. Weygoldt (1979) suggested the existence of two families was not supported by the available data, and Haupt & Song (1996) formally reduced the Hypoctonidae to a subfamily as there was little support for a monophyletic Hypoctonidae. Dunlop & Horrocks (1996) suggested that the hypoctonids may be the sister-group to the Schizomida and Proschizomus Dunlop & Horrocks 1996, but the character polarities they utilized were regarded as uncertain and many features of Proschizomus were not observable in the fossilized material.
- Found in Aristoteles' work: De Anim. Hist., Lib: IV Cap: I.
- Günther Schmidt (1993). Giftige und gefährliche Spinnentiere [Poisonous and dangerous arachnids] (in German). Westarp Wissenschaften. ISBN 3-89432-405-8.
- Orin McMonigle (2008). Whipscorpions and Whipspiders: Culturing Gentle Monsters. Elytra and Antenna Insect Books. 40pp.
- J. Mark Rowland & John A. L. Cooke (1973). "Systematics of the arachnid order Uropygida (=Thelyphonida)" (PDF). Journal of Arachnology 1: 55–71.
- P. Weygoldt (1979). "Thelyphonellus ruschii n. sp. und die taxonomische Stellung von Thelyphonellus Pocock 1894 (Arachnida: Uropygi: Thelyphonida)". Senckenbergiana Biologica 60: 109–114.
- J. Haupt & D. Song (1996). "Revision of East Asian whip scorpions (Arachnida Uropygi Thelyphonida). I. China and Japan". Arthropoda Selecta 5: 43–52.
- J. A. Dunlop & C.A. Horrocks (1996). "A new Upper Carboniferous whip scorpion (Arachnida: Uropygi: Thelyphonida) with a revision of the British Carboniferous Uropygi". Zoologischer Anzeiger 234: 293–306.
- M. S. Harvey (2002). "The neglected cousins: what do we know about the smaller arachnid orders?" (PDF). Journal of Arachnology 30: 357–372. doi:10.1636/0161-8202(2002)030[0357:TNCWDW]2.0.CO;2.
|Wikimedia Commons has media related to: Thelyphonida|
- Pictures of a Mexican Uropygid sp. and its habitat
- Photos of Taiwanese Uropygid - Typopeltis crucifer
- Video of a vinegarroon
- Video of vinegaroon mating behavior