Purse-web Spider
Antrodetus unicolor
Atypidae (Purse-web Spiders), Order Araneae
Physical Description
Robust, glossy body with a heavily sclerotized, shiny dark brown to black cephalothorax and large, prominent chelicerae (jaws) pointing forward. The abdomen is typically oval, slightly paler brown or greyish-brown, and relatively plump.
Size Estimate
Body length ranges from 10 to 20 millimeters, with a compact leg span of roughly 25 to 35 millimeters. This specimen appears to be an adult or sub-adult male wandering in search of a mate.
Coloration & Markings
Deep, glossy mahogany brown to jet black across the carapace and legs. The abdomen is a duller, contrasting brown or greyish tone, often lacking distinct patterns.
Web Type
Tube web or purse web. They construct a distinctive closed silken tube that extends from an underground burrow up the base of a tree or along the ground.
Eye Arrangement
Eight small eyes clustered closely together on a distinct elevated tubercle at the front center of the carapace, typical of mygalomorph spiders.
Leg Characteristics
Short, thick, powerful legs adapted for burrowing and gripping prey through silk. They feature robust claws and lack specialized claw tufts, reflecting their ground-dwelling nature.
Venom & Safety Information
Venom Information
Contains mild mycotoxins and neurotoxins used to immobilize small insect prey. Not medically significant to humans.
Medical Significance
Harmless to humans. While they possess large, formidable fangs capable of delivering a painful mechanical puncture, bites are extremely rare and result in only minor local irritation.
Safety Recommendations
Leave the spider alone or gently relocate it using a container if found indoors. There is no danger to humans or pets.
Habitat & Behavior
Habitat & Range
Found primarily in wooded areas, deciduous forests, and shaded banks where they can burrow into moist, undisturbed soil.
Behavior & Temperament
Secretive and largely subterranean. Females spend nearly their entire lives inside their burrows, while wandering males occasionally leave to search for females. They are docile unless severely provoked.
Diet & Prey
Insects and other small arthropods that walk over the silk purse web. The spider punctures the web from the inside to drag prey through the silk.
Seasonal Activity
Most frequently encountered in autumn, particularly adult males wandering in the open to find mates.
Description
The purse-web spider is a fascinating and rarely seen mygalomorph relative of tarantulas. With its shiny dark carapace and massive forward-facing fangs, it looks intimidating, but it spends almost its entire life hidden away in underground burrows.
Key Features
Extremely large, forward-pointing chelicerae (jaws), glossy dark carapace, compact robust body, and absence of an orb web.
Similar Species
Trapdoor spiders (Ctenizidae) and small tarantulas. Distinguished by their unique silken purse-web construction and eye tubercle arrangement.
Life Cycle
Females lay eggs inside the safety of their underground burrows. Spiderlings overwinter with the mother before dispersing. Purse-web spiders are exceptionally long-lived, with females living up to 7 to 10 years.
Ecological Importance
Acts as a specialized predator of forest-floor invertebrates, helping regulate local insect populations.
Conservation Status
Not evaluated by the IUCN, but populations can be locally vulnerable to habitat destruction and deforestation.
Interesting Facts
Purse-web spiders hunt by waiting inside a closed silken tube for an insect to land on the outside, then impaling the prey right through the silk wall and pulling it inside to feed.
Photography Tips
Photograph from a low angle with macro lighting to highlight the glossy carapace and impressive jaw structure without causing stress to the spider.
Identified: 2026-08-18T16:00:54.995247