--- title: "Arachnids & Scorpions (Arachnida) | Evolutionary Clade | AnimalTracks.wiki" description: "Eight segmented legs, hydraulic joint movement, liquid external digestion, and silk spinning. Explore 22 species in the Arachnids & Scorpions evolutionary lineage." image: "https://animaltracks.wiki/icon-512.png" --- # Arachnids & Scorpions (*Arachnida*) > Eight segmented legs, hydraulic joint movement, liquid external digestion, and silk spinning. Arachnids are ancient chelicerate hunters lacking wings or antennae. They move limbs using hydraulic blood pressure rather than opposing extensor muscles, paralyze prey with peptide venom delivered via fangs or stingers, and dissolve food externally before consuming liquid nutrients. Horseshoe crabs are filed here too. They are not arachnids but fellow chelicerates, more closely related to spiders and scorpions than to true crabs. ## Key Evolutionary Adaptations - Spiders extend their legs by pumping hemolymph fluid under hydraulic pressure through cephalothorax chambers. - Spider dragline silk exhibits tensile strength matching high-grade alloy steel while stretching up to 40 percent. - Scorpions fluoresce vivid blue-green under ultraviolet light due to beta-carboline compounds in their cuticles. ## Member Species (22 Creatures) - [Arizona Bark Scorpion](https://animaltracks.wiki/animals/arizona-bark-scorpion/) (*Centruroides sculpturatus*) - **Superpower**: The best climber among Arizona's scorpion species, paired with venom that drives nerve axons into prolonged and excessive firing. - **Musical Match**: Acid King (Stoner Rock & Desert Groove) - [Atlantic Horseshoe Crab](https://animaltracks.wiki/animals/atlantic-horseshoe-crab/) (*Limulus polyphemus*) - **Superpower**: Blue blood that clots when it meets certain bacteria, which labs use to test medicines and medical devices for endotoxins. - **Musical Match**: Philip Glass (Neo-Classical & Baroque Chamber) - [Bold Jumping Spider](https://animaltracks.wiki/animals/bold-jumping-spider/) (*Phidippus audax*) - **Superpower**: Sneaks up and pounces on prey, trailing a silk safety line - **Musical Match**: Eville (Nu-Metal & Heavy Alt-Metal) - [Brazilian Wandering Spider](https://animaltracks.wiki/animals/brazilian-wandering-spider/) (*Phoneutria nigriventer*) - **Superpower**: Venom peptides that jam voltage-gated sodium and calcium channels and the nicotinic acetylcholine receptor - **Musical Match**: Jorge Ben Jor (Classic Funk, Soul & Disco) - [Brazilian Yellow Scorpion](https://animaltracks.wiki/animals/brazilian-yellow-scorpion/) (*Tityus serrulatus*) - **Superpower**: Parthenogenesis: adult scorpions are usually female, and unfertilized eggs develop straight into daughters, and a female breeds with no male present. - **Musical Match**: CSS (Dance-Punk & Electroclash) - [Brown Recluse](https://animaltracks.wiki/animals/brown-recluse/) (*Loxosceles reclusa*) - **Superpower**: Venom that can kill the tissue around its bite - **Musical Match**: The Cure (Gothic Rock & Post-Punk) - [Carolina Wolf Spider](https://animaltracks.wiki/animals/carolina-wolf-spider/) (*Hogna carolinensis*) - **Superpower**: Carries its spiderlings on its back, and those that stay with her learn mazes better - **Musical Match**: Pixies (90s Grunge & Alt-Rock) - [Chilean Rose Tarantula](https://animaltracks.wiki/animals/tarantula/) (*Grammostola rosea*) - **Superpower**: No extensor muscles at two leg joints, where blood pressure may work against the flexors - **Musical Match**: Duster (Slowcore & Minimal Indie) - [Deathstalker Scorpion](https://animaltracks.wiki/animals/deathstalker-scorpion/) (*Leiurus quinquestriatus*) - **Superpower**: A venom peptide, chlorotoxin, that binds brain tumor cells and, built into the dye tozuleristide, made gliomas glow in a trial published in 2019 - **Musical Match**: Gesaffelstein (French Dark Electro & EBM) - [Deer Tick](https://animaltracks.wiki/animals/deer-tick/) (*Ixodes scapularis*) - **Superpower**: Ambushes a passing host, then feeds for days while its new, flexible outer shell helps it swell - **Musical Match**: Warpaint (Dream Pop & Shoegaze) - [Desert Hairy Scorpion](https://animaltracks.wiki/animals/desert-hairy-scorpion/) (*Hadrurus arizonensis*) - **Superpower**: Digs burrows up to 2.5 meters deep to escape desert heat, and senses vibrations in the air and the ground through its body hairs. - **Musical Match**: Truckfighters (Stoner Rock & Desert Groove) - [Egyptian Giant Solpugid](https://animaltracks.wiki/animals/egyptian-giant-solpugid/) (*Galeodes arabs*) - **Superpower**: Camel spider jaws reach up to one-third of body length - **Musical Match**: Megadeth (Thrash Metal & Speed Metal) - [Emperor Scorpion](https://animaltracks.wiki/animals/emperor-scorpion/) (*Pandinus imperator*) - **Superpower**: Huge, powerful pincers generally used to tear prey apart instead of stinging it, plus a cuticle that fluoresces blue-green under ultraviolet light. - **Musical Match**: The Crystal Method (Big Beat & 90s Acid Techno) - [European Harvestman](https://animaltracks.wiki/animals/european-harvestman/) (*Phalangium opilio*) - **Superpower**: In a lab colony, a female lays a typical clutch of about 250 eggs roughly every three days - **Musical Match**: American Football (Math Rock & Midwest Emo) - [Giant Huntsman Spider](https://animaltracks.wiki/animals/giant-huntsman-spider/) (*Heteropoda maxima*) - **Superpower**: A leg span of up to 30 cm - **Musical Match**: Lustmord (Glacial Ambient & Drone Soundscapes) - [Goliath Birdeater](https://animaltracks.wiki/animals/goliath-birdeater/) (*Theraphosa blondi*) - **Superpower**: An 11-inch leg span and stinging hairs it can release to irritate predators - **Musical Match**: A Tribe Called Quest (90s East Coast Hip-Hop & Boom Bap) - [Long-Bodied Cellar Spider](https://animaltracks.wiki/animals/long-bodied-cellar-spider/) (*Pholcus phalangioides*) - **Superpower**: Spins its body into a blur when its web is disturbed, and walks into other spiders' webs to eat them - **Musical Match**: My Bloody Valentine (Dream Pop & Shoegaze) - [Peacock Spider](https://animaltracks.wiki/animals/peacock-spider/) (*Maratus volans*) - **Superpower**: A hidden abdominal fan, waved in time with the third pair of legs, and vibrations sent through the ground - **Musical Match**: Earth, Wind & Fire (Classic Funk, Soul & Disco) - [Southern Black Widow](https://animaltracks.wiki/animals/southern-black-widow/) (*Latrodectus mactans*) - **Superpower**: Venom that acts on the motor endplate to allow a massive release of noradrenaline and acetylcholine, causing excessive stimulation and fatigue of the muscle. - **Musical Match**: Intervals (Math Rock & Instrumental Virtuoso) - [Spitting Spider](https://animaltracks.wiki/animals/spitting-spider/) (*Scytodes thoracica*) - **Superpower**: Fires a zigzag spray of silk, glue and venom at up to 28.8 meters a second, then bites once the glue is dry - **Musical Match**: Igorrr (Breakcore & Chaotic Drill) - [Striped Bark Scorpion](https://animaltracks.wiki/animals/striped-bark-scorpion/) (*Centruroides vittatus*) - **Superpower**: A venom peptide, CvIV4, that slows the closing of Nav1.7, a sodium channel in pain-sensing nerves, plus a defense split by sex: in lab tests males sprinted faster and females stung faster. - **Musical Match**: ZZ Top (Classic Hard Rock & Southern Blues) - [Sydney Funnel-Web Spider](https://animaltracks.wiki/animals/sydney-funnel-web-spider/) (*Atrax robustus*) - **Superpower**: Robustoxin (delta-atracotoxin-Ar1), a 42-amino-acid peptide in male venom that stops some sodium channels in nerve cells from switching off properly. Its toxin family likely evolved to deter vertebrate predators such as bandicoots, birds and lizards, but robustoxin severely affects the nervous systems of humans and monkeys. - **Musical Match**: Joan Jett & the Blackhearts (Classic Hard Rock & Southern Blues) ```json { "@context": "https://schema.org", "@graph": [ { "@type": "CollectionPage", "@id": "https://animaltracks.wiki/clades/arachnids/#collection", "name": "Arachnids & Scorpions (Arachnida)", "description": "Eight segmented legs, hydraulic joint movement, liquid external digestion, and silk spinning.", "url": "https://animaltracks.wiki/clades/arachnids/", "mainEntity": { "@type": "ItemList", "itemListElement": [ { "@type": "ListItem", "position": 1, "name": "Arizona Bark Scorpion", "url": "https://animaltracks.wiki/animals/arizona-bark-scorpion/" }, { "@type": "ListItem", "position": 2, "name": "Atlantic Horseshoe Crab", "url": "https://animaltracks.wiki/animals/atlantic-horseshoe-crab/" }, { "@type": "ListItem", "position": 3, "name": "Bold Jumping Spider", "url": "https://animaltracks.wiki/animals/bold-jumping-spider/" }, { "@type": "ListItem", "position": 4, "name": "Brazilian Wandering Spider", "url": "https://animaltracks.wiki/animals/brazilian-wandering-spider/" }, { "@type": "ListItem", "position": 5, "name": "Brazilian Yellow Scorpion", "url": "https://animaltracks.wiki/animals/brazilian-yellow-scorpion/" }, { "@type": "ListItem", "position": 6, "name": "Brown Recluse", "url": "https://animaltracks.wiki/animals/brown-recluse/" }, { "@type": "ListItem", "position": 7, "name": "Carolina Wolf Spider", "url": "https://animaltracks.wiki/animals/carolina-wolf-spider/" }, { "@type": "ListItem", "position": 8, "name": "Chilean Rose Tarantula", "url": "https://animaltracks.wiki/animals/tarantula/" }, { "@type": "ListItem", "position": 9, "name": "Deathstalker Scorpion", "url": "https://animaltracks.wiki/animals/deathstalker-scorpion/" }, { "@type": "ListItem", "position": 10, "name": "Deer Tick", "url": "https://animaltracks.wiki/animals/deer-tick/" }, { "@type": "ListItem", "position": 11, "name": "Desert Hairy Scorpion", "url": "https://animaltracks.wiki/animals/desert-hairy-scorpion/" }, { "@type": "ListItem", "position": 12, "name": "Egyptian Giant Solpugid", "url": "https://animaltracks.wiki/animals/egyptian-giant-solpugid/" }, { "@type": "ListItem", "position": 13, "name": "Emperor Scorpion", "url": "https://animaltracks.wiki/animals/emperor-scorpion/" }, { "@type": "ListItem", "position": 14, "name": "European Harvestman", "url": "https://animaltracks.wiki/animals/european-harvestman/" }, { "@type": "ListItem", "position": 15, "name": "Giant Huntsman Spider", "url": "https://animaltracks.wiki/animals/giant-huntsman-spider/" }, { "@type": "ListItem", "position": 16, "name": "Goliath Birdeater", "url": "https://animaltracks.wiki/animals/goliath-birdeater/" }, { "@type": "ListItem", "position": 17, "name": "Long-Bodied Cellar Spider", "url": "https://animaltracks.wiki/animals/long-bodied-cellar-spider/" }, { "@type": "ListItem", "position": 18, "name": "Peacock Spider", "url": "https://animaltracks.wiki/animals/peacock-spider/" }, { "@type": "ListItem", "position": 19, "name": "Southern Black Widow", "url": "https://animaltracks.wiki/animals/southern-black-widow/" }, { "@type": "ListItem", "position": 20, "name": "Spitting Spider", "url": "https://animaltracks.wiki/animals/spitting-spider/" }, { "@type": "ListItem", "position": 21, "name": "Striped Bark Scorpion", "url": "https://animaltracks.wiki/animals/striped-bark-scorpion/" }, { "@type": "ListItem", "position": 22, "name": "Sydney Funnel-Web Spider", "url": "https://animaltracks.wiki/animals/sydney-funnel-web-spider/" } ] } } ] } ```