South American Toothed-Hacklemesh Weaver
Metaltella simoni
Desidae (Desid Spiders), Order Araneae. Formerly placed in Amphinectidae. They are distinguished by their cribellate (hackled) silk and toothed chelicerae.
Physical Description
A medium-sized spider with a somewhat flattened, elongated cephalothorax and an oval-shaped abdomen. The body is covered in fine, dense hairs giving it a velvety appearance. The chelicerae (fangs) are prominent and often robust in adult specimens.
Size Estimate
Body length typically ranges from 7-10mm (0.28-0.4 inches). Leg span can reach 25-35mm. The specimen in the image appears to be a sub-adult or adult female.
Coloration & Markings
Overall dark brown to charcoal gray-black. The cephalothorax is usually darker than the abdomen. The abdomen may show faint lighter chevrons or a mottled pattern toward the posterior, though it often appears solid dark in low light.
Web Type
Builds a messy, hackled (cribellate) web that lacks a structured orb shape. Often found in a small funnel-like retreat or a flat sheet-like tangle under debris, bark, or in crevices.
Eye Arrangement
Eight eyes arranged in two rows. The rows are slightly curved, which is a common feature of many ground-dwelling and hacklemesh weavers, though specific eye details are obscured in this image.
Leg Characteristics
The legs are relatively long and sturdy, matching the body color. They are equipped with noticeable spines (macrosetae). This species typically holds its first two pairs of legs forward when resting or hunting.
Venom & Safety Information
Venom Information
Possesses a harmless venom designed to paralyze small insects. It is not considered neurotoxic or cytotoxic to humans.
Medical Significance
Low. Bites are rare and generally result in minor localized pain, redness, or itching similar to a bee sting. No special medical treatment is usually required unless an allergic reaction occurs.
Safety Recommendations
Harmless. If found indoors, they can be easily relocated using a cup and a piece of paper. Wear gloves when gardening in woodpiles or leaf litter to avoid accidental 'defensive' nips.
Habitat & Behavior
Habitat & Range
Native to South America (Argentina, Uruguay, Brazil) but widely introduced to the Southern United States (California to Florida). Found in urban gardens, under logs, in leaf litter, and occasionally wandering inside homes.
Behavior & Temperament
An ambush hunter that stays near its web retreat. It is primarily nocturnal. The species is timid and will typically retreat rapidly if disturbed, only biting if directly squeezed or trapped against skin.
Diet & Prey
Generalist insectivore, feeding on ants, crickets, beetles, and other small arthropods that blunder into its messy web or wander near its retreat.
Seasonal Activity
Active year-round in warmer climates, but most visible to homeowners during the autumn when they may wander indoors seeking shelter or mates.
Description
Metaltella simoni is a common but often overlooked immigrant spider. Often mistaken for more dangerous species due to its dark color, it is actually a beneficial resident that helps control household and garden pests. It prefers damp, dark environments.
Key Features
Velvety dark appearance, elongated oval abdomen, prominent front-facing legs with spines, and a preference for messy 'hackled' silk webs in crevices.
Similar Species
Often confused with the Black Widow (which has a glossy finish and red hourglass) or the Brown Recluse (which has a violin marking). It is most similar to other Hacklemesh weavers in the Amaurobiidae family.
Life Cycle
Females produce a flat, white, disc-like egg sac usually hidden within the web retreat. Spiderlings emerge and disperse. They may live for 1 to 2 years depending on environmental conditions.
Ecological Importance
Serves as an important suburban predator, specifically controlling populations of invasive ants and beetles in areas where it has been introduced.
Conservation Status
Not evaluated by IUCN, but considered stable and expanding in its introduced range in North America.
Interesting Facts
This spider is a 'synanthrope,' meaning it has successfully followed human expansion, hitchhiking in cargo and landscaping materials to establish large populations across North America.
Photography Tips
Since they are dark and velvety, use a diffused light source to bring out the texture of the hair and the shape of the cephalothorax. A top-down macro shot helps identify the abdomen pattern.
Identified: 2026-07-14T17:00:11.196483