Audouin's Trapdoor Spider, Cork-lid Trapdoor Spider
Ummidia audouini
Halonoproctidae (Trapdoor Spiders), Order Araneae. Characteristics include a stocky build and downward-acting fangs (Mygalomorphae).
Physical Description
A robust, heavily armored spider with a shiny, glabrous (hairless) cephalothorax. The abdomen is rounded and velvet-like. They possess powerful chelicerae (fangs) designed for digging.
Size Estimate
Body length 15-25mm; Leg span 30-45mm. This specimen appears to be an adult male based on the length of the legs relative to the body and its presence above ground.
Coloration & Markings
Almost entirely jet black or dark chocolate brown. The cephalothorax has a high-gloss, patent-leather appearance, while the abdomen is more matte.
Web Type
Does not build an aerial web. Constructs a deep Silk-lined vertical burrow in the ground, capped with a thick, hinged 'cork-lid' made of silk, soil, and moss.
Eye Arrangement
Small eye tubercle located at the front-center of the carapace containing 8 eyes arranged in a compact, rectangular group typical of Mygalomorphs.
Leg Characteristics
Thick, powerful legs used for digging. The front legs often feature specialized spines (rastellum) used to excavate soil. Adult males have longer, more slender legs than females.
Venom & Safety Information
Venom Information
Possesses venom used to tranquilize prey. It is not considered chemically dangerous to humans, though the large fangs can cause a painful mechanical puncture.
Medical Significance
Low medical significance. Bites are rare and usually only result in localized pain and swelling. No systemic neurotoxic or necrotic effects are expected.
Safety Recommendations
If found indoors, relocate using a cup and stiff paper. Wear gloves if gardening in areas where they burrow. Treat bites with basic first aid (cleaning and ice).
Habitat & Behavior
Habitat & Range
Primarily the Southeastern United States. Prefers deciduous forests, wooded slopes, and undisturbed garden soil where embankments provide good drainage.
Behavior & Temperament
Normally reclusive and subterranean. They are ambush predators that wait behind their door. If encountered above ground (usually males seeking mates), they can be defensive, rearing up and baring fangs.
Diet & Prey
Insects, beetles, crickets, and occasionally other spiders. They detect vibrations through the soil and lunge out of the burrow to grab prey.
Seasonal Activity
Females are year-round but hidden. Males are most active on the surface during late summer and fall, particularly after rain events.
Description
A striking, primitive-looking spider that resembles a miniaturized tank. Its glossy black armor and thick legs make it a fascinating example of the Mygalomorphae suborder, often mistaken for small tarantulas.
Key Features
Glossy 'patent leather' cephalothorax, thick digging legs, and a saddle-like depression (tibia III) on the third pair of legs.
Similar Species
Often confused with Mouse Spiders (Actinopus) or the Sydney Funnel-web (in Australia), but distinguished by the specific leg anatomy and the absence of long spinnerets.
Life Cycle
Slow-growing; can live for several years (females up to 10-15 years). Males emerge from burrows after heavy rain in summer/autumn to find females, after which they usually die.
Ecological Importance
Critical for soil health through aeration and as a natural controller of ground-dwelling insect populations. They serve as food for spider-hunting wasps (Pompilidae).
Conservation Status
Not listed by IUCN, but local populations are threatened by habitat fragmentation and the use of heavy pesticides on lawns.
Interesting Facts
The 'cork' door they build is so well camouflaged that it is virtually invisible when closed. They spend 99% of their lives underground.
Photography Tips
Get a low-angle shot to show the fangs and eye tubercle. Use a ring light or flash to capture the texture variations between the glossy head and matte abdomen.
Identified: 2026-06-14T12:15:31.635059