Running Crab Spiders: How to Identify

Running crab spiders, genus Philodromus occur in Europe, eastern Asia, North America, Central America, and South Africa. There are more than 250 described Philodromus species worldwide, at least 55 species in North America north of Mexico.

Running crab spiders: Identification.

Adult running crab spiders range from less than 1/10 to 2/5 of an inch in length.

Their bodies are colored brown, black, and tan, providing excellent camouflage for sitting motionless on dead leaves and tree trunks.

The carapace of the upper part of its body is nearly round and more prolonged than wide. Its tiny eyes are equal in size and organized into two neat rows. Additionally, its delicate jaw-like mouthparts (chelicerae) lack sharp teeth.

The abdomen is elongated, broader towards the back, and wider than long. The first two pairs of legs are longer than the third and fourth. Notably, the second pair is particularly lengthy; however, they do not exceed double their corresponding length counterparts. For each leg segment named ‘tarsus,’ two claws are present along with a dense bundle of microscopic hairs that appear underneath (scopula) alongside another set at its tip (claw tuft). All three features may be invisible if viewed by the naked eye alone.

For Running crab spiders, speed is everything.

Running crab spiders are fast-moving spiders that run over the ground and climb trees and walls.

Not only do these Running Crab Spiders outrun their predators, but they are also swift enough to evade human capture. Unlike other spiders, this species does not spin webs; instead, it pursues its prey on foot before delivering a paralyzing bite and consuming the insect when convenient. Thankfully, although lightning fast in motion, Running Crab Spiders remain relatively small creatures – providing some relief for those frightened of them!

Running crab spiders have a crab-like form due to the first two sets of legs shifting outwards. Although this might appear identical to the true crab spiders, these families are not necessarily related. Unlike other spider species that feature disproportionally sized limbs, the Running crab spider’s legs are usually similar in size, although their second set may be marginally longer than its predecessor.

Ebo spiders are particularly noteworthy because the second set of legs is twice as long as the first in certain species. In addition, philodromids boast scopulas only at their tarsi tips and eyes, which align in two rows – both curved with a wider posterior row than the anterior one. These arachnids generally display light brown or creamy hues accompanied by faint longitudinal stripes.