Sidymella trapezia
Trapezoid Crab Spider Identification Australia
Small pale square-ended crab spider of eastern Australian foliage, with long front legs and a trapezium-shaped abdomen.
Usually low riskThe Trapezoid crab spider is Sidymella trapezia, a small crab spider that relies on camouflage and ambush rather than a capture web. Current catalogues place it in Queensland and New South Wales. It is a useful comparison when a pale, semi-transparent spider is sitting still on foliage, bark or garden plants, but the square-ended body and long front legs overlap other Sidymella and related crab spiders.
Quick identification
- Small pale crab-spider body on foliage, bark or garden surfaces
- Front legs longer and held out to the sides, with the legs relatively even in size
- Squared or trapezium-shaped abdomen rather than a round orb-weaver body
- Sits still to ambush insects instead of using a capture web
What to check next
Check for the crab-like stance, long front legs, pale semi-transparent body and trapezium outline. Compare with other Sidymella and with red-tipped square-ended crab spiders if paired red humps or red patches are visible. Keep the result at crab spider or Sidymella when the dorsal outline is unclear.
When to seek medical help
This spider is not usually considered dangerous. Seek medical advice for severe pain, allergic symptoms, infection signs, spreading symptoms or uncertainty after any bite.
Where it is usually seen
Garden foliage, shrubs, bark, native vegetation, leaves and low plants in Queensland and New South Wales, where small insects pass close enough for ambush hunting.