Philodromus rufus pacificus

Banks, 1898

Pacific running crab spider

Philodromus rufus pacificus is a of running crab spider to the Pacific Northwest of the United States. It belongs to the Philodromidae, a group known for their laterigrade leg orientation that permits sideways movement. The subspecies is distinguished from the nominate form by specific morphological traits. Running crab spiders are sit-and-wait that do not build webs for prey capture.

Philodromus rufus pacificus by (c) Claus Giloi, some rights reserved (CC BY), uploaded by Claus Giloi. Used under a CC-BY license.

Pronunciation

How to pronounce Philodromus rufus pacificus: /ˌfɪl.əˈdroʊ.məs ˈru.fəs pəˈsɪ.fɪ.kəs/

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Identification

Distinguished from Philodromus rufus by its light grey (as opposed to darker eye coloration in the nominate ), bullet-shaped , and more laterally extended leg posture. The Pacific Northwest distribution provides geographic separation from other P. rufus . Examination of eye coloration and abdominal shape is necessary for confident identification.

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Appearance

Characterized by completely light grey , a bullet-shaped , and a more spread-out leg structure than the parent Philodromus rufus. The body form is typical of philodromid spiders with a somewhat flattened profile adapted for moving through vegetation.

Habitat

Specific preferences are not documented in available sources. As a member of Philodromidae, it likely occurs in vegetation where its sideways-running locomotion provides advantage.

Distribution

to the Pacific Northwest of the United States; restricted to the west coast of North America. The has been documented in this region based on collection records and observational data.

Behavior

As a running crab spider ( Philodromidae), it exhibits laterigrade leg orientation permitting sideways movement. Members of this family are sit-and-wait that do not construct capture webs, instead actively pursuing or ambushing prey on vegetation surfaces.

Similar Taxa

Philodromus rufus (nominate subspecies)Overlaps in general but differs in coloration (not light grey), abdominal shape (less distinctly bullet-shaped), and leg structure (less spread out). Geographic separation with nominate occurring outside the Pacific Northwest.

More Details

Taxonomic Note

The was described by Banks in 1898. GBIF records show distribution data for the broader including regions outside the Pacific Northwest, but these likely represent the nominate subspecies or other related rather than P. r. pacificus specifically.