Philodromus marxi
Keyserling, 1884
Metallic Crab Spider
Philodromus marxi is a running crab spider in the Philodromidae, commonly known as the metallic crab spider. The exhibits strong : males have a smooth, metallic sheen while females are bristly and colored white and grey. It is found throughout the United States and is frequently encountered in human dwellings, including bathrooms and showers.
Pronunciation
How to pronounce Philodromus marxi: //fɪˈlɒdrəməs ˈmɑːrksi//
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Identification
Males are distinguished by a smooth, metallic sheen; females are bristly with white and grey coloration. As a running crab spider, it has laterally flattened legs adapted for sideways movement, distinguishing it from true crab spiders (Thomisidae) which move forward and backward.
Images
Habitat
Found in human-modified environments including houses, bathrooms, and showers; also occurs in natural settings.
Distribution
United States.
Behavior
Has been observed entering showers and bathtubs, where individuals may become trapped by smooth surfaces. Some individuals appear to wander into these spaces while seeking moisture or shelter.
Human Relevance
Frequently encountered indoors, particularly in bathrooms and showers. Poses no known danger to humans; often generates alarm due to unexpected proximity during bathing.
Similar Taxa
- Tegenaria domestica (Barn Funnel Weaver)Both are commonly found in showers and bathtubs; T. domestica is distinguished by funnel web construction and more robust body form.
- Philodromus spp. (other running crab spiders)Share laterally flattened legs and sideways movement; P. marxi is identified by the distinctive metallic sheen in males and bristly white-grey females.