Amblypygi

Distinguished from spiders by lack of spinnerets and venom; from scorpions by absence of tail and stinger; from whip scorpions (Uropygi/Thelyphonida) by lack of flagellum and presence of only six walking legs. The extraordinarily long, whip-like first pair of legs is diagnostic. Pedipalp structure varies by genus—some possess extremely elongate, spine-free pedipalps (Euphrynichus), others have heavily spined, shorter pedipalps. Sexual dimorphism in pedipalp length present in some species, with males having longer pedipalps extending past the "knee" of the first walking leg.

Tropical and subtropical regions worldwide. Found in warm, humid microhabitats: leaf litter, caves, under bark, rock crevices, tree holes, and soil galleries. Some species are subterranean. Phrynus marginemaculatus occurs under coral stones and rocks near beaches, tolerating periodic flooding through plastron respiration. Captive specimens require tall enclosures with vertical climbing surfaces, 70–75°F temperature, and humidity above 75%.

Pantropical and subtropical distribution. Records from Central and South America, Africa (including Madagascar), southern Asia, and Caribbean/Antillean islands. Phrynus marginemaculatus represents the northernmost extent in southern Florida. Heterophrynus cheiracanthus recently documented in southeastern Brazil (Cerrado). Sarax ioanniticus reported from Cyprus. Fossil record extends to Carboniferous period (Weygoldtina).

Strictly nocturnal. Activity patterns tied to darkness; retreat to hiding places during daylight. In laboratory conditions, Tarantula marginemaculata breeds during summer months. Adults may live 5–10 years in captivity.

Opportunistic predators feeding primarily on arthropods: crickets, cockroaches, spiders, moths. Small vertebrates including lizards and fish have been documented. Prey located using antenniform legs, seized with spined pedipalps, then pulverized by chelicerae with digestive enzymes added to liquefy meal. Pre-molt fasting common; individuals may go over one month without feeding.

Egg development approximately 98 days. Postembryonic development to maturity requires 8–10 months with 5–8 molts. Mature individuals continue molting and growing throughout life. Females produce 1–2 broods annually. Young hatch from eggs carried in sac under abdomen; 1st-instar nymphs climb onto mother's back and remain for several weeks. Nymphs that fall off before first molt do not survive.

Nocturnal sit-and-wait predators. Use antenniform legs to detect prey, mates, and threats in complete darkness; these legs can sweep nearly 360° around the body. When threatened, retreat rapidly rather than attack; capable of blinding sideways speed. Some species demonstrate remarkable homing ability, returning to refuges after displacement of 30+ feet. Agonistic encounters between males involve grasping opponent's third leg tibiae and pushing upward/backward. Mating involves male depositing stalked spermatophores on substrate, guiding female over them with pedipalps; female presses levers to elevate sperm packages for uptake by genital structures.

Mid-level predators in tropical and subtropical food webs. Control populations of insects and other arthropods. Prey for vertebrate predators; their speed and crevice-dwelling habits serve as primary defenses given lack of chemical or venomous defenses.

Several genera kept as pets (Acanthophrynus, Damon, Euphrynichus, Heterophrynus, Phrynus, Paraphrynus, Phrynichus, Charinus, Charon). Require specialized tall enclosures with climbing surfaces. Harmless to humans—lack venom and rarely bite; can deliver thorn-like puncture wounds with pedipalps if handled carelessly. Frequently subject to viral misidentification as "giant spiders" or dangerous creatures.

• Uropygi (Thelyphonida)Whip scorpions or vinegaroons possess flagellum (tail) and have eight walking legs; Amblypygi lack tail and use only six legs for walking.
• Araneae (spiders)Spiders possess spinnerets for silk production and venom glands; Amblypygi lack both, and have highly modified sensory first legs unlike any spider.
• ScorpionesTrue scorpions have segmented tail with terminal stinger and pedipalps as pincers; Amblypygi lack tail entirely and have raptorial rather than pincer-like pedipalps.

Despite menacing appearance and common names including "whip scorpion," amblypygids are entirely harmless to humans. Viral videos frequently misidentify them as giant spiders or dangerous arachnids. They do not possess venom, cannot sting, and rarely bite; defensive behavior consists of rapid retreat or, if cornered, grabbing with spined pedipalps that may cause minor puncture wounds.

• arachnid
• nocturnal
• predator
• tropical
• cave-dwelling
• maternal care
• pet trade

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• At night in the rainforest: Whip spiders, Amblypygi — Bug of the Week
• At night in the rainforest with scary whip spiders: Amblypygids — Bug of the Week
• Whips in Xibalba: Whip spiders, Amblypygi — Bug of the Week
• Bug Eric: February 2016
• Damon diadema—Tanzanian giant tailless whip scorpion | Beetles In The Bush
• Mother and daughter (perhaps) | Beetles In The Bush
• Kampf, Paarungsverhalten, Spermatophorenmorphologie und weibliche Genitalien bei neotropischen Geißelspinnen (Amblypygi, Arachnida) Agonistic and mating behaviour, spermatophore morphology, and female genitalia in neotropical whip spiders (Amblypygi, Arachnida)
• Amblypygi (Arachnida) occurrence in a protected area from the Brazilian Cerrado
• Lebenszyklus und postembryonale entwicklung der geibelspinne Tarantula marginemaculata C. L. Koch (Chelicerata, Amblypygi) im laboratorium Life cycle and postembryonic development of the tailless whip scorpion, Tarantula marginemaculata (Chelicerata, Amblypygi) in the laboratory
• Beobachtungen zur fortpflanzungsbiologie und zum verhalten der geißelspinne tarantula marginemaculata C. L. Koch (Chelicerata, Amblypygi) Observations on the reproductive biology and behaviour of the American tailless whip scorpion, Tarantula marginemaculata C. L. Koch (Amblypygi, Tarantulidae)
• First report of a Tailless Whip Scorpion in Cyprus: the case of Saraxioanniticus (Kritscher, 1959) (Amblypygi, Charontidae).