Philodromidae is a family of spiders commonly known as philodromid crab spiders or running crab spiders. This family is superficially similar to the "true" crab spiders in the family Thomisidae.

However, studies have shown that these families are not as closely related as previously thought. Unlike thomisids, philodromids tend to have few true setae (hairs or spines) on their bodies. They also lack the congruent eye tubercles of some thomisids. The second legs are usually the longer of the four pairs of walking legs and in the genus Ebo this is quite extreme, with the second pair of legs in some species twice as long as the first pair.

The most common genus is Philodromus which, like Ebo is widespread. Other common genera include the elongate grass-dwelling Tibellus and the widespread Thanatus, which includes the widely distributed Holarctic house crab spider Thanatus vulgaris. This species commonly captures flies on and in buildings.

The family contains over 500 species in nearly 30 genera. Most are dull colored- brown, gray, yellowish or mottled, and seldom reach above 10 mm in body length. Most have a leaf-like cardiac mark on the anterior dorsal abdomen. None of the species build webs, but they do use silk for draglines and for egg sacs.

Genera

The categorization into subfamilies follows Joel Hallan's Biology Catalog.

• Pedinopisthinae

• Pagiopalus Simon, 1900 (Hawai'i)
• Pedinopistha Karsch, 1880 (Hawai'i)

• Philodrominae

• Apollophanes O. P-Cambridge, 1898 (USA to Panama, India, Russia, Korea)
• Bacillocnemis Mello-Leitão, 1938 (Argentina)
• Berlandiella Mello-Leitão, 1929 (Brazil)
• Cleocnemis Simon, 1886 (South America)
• Ebo Keyserling, 1884 (Argentina, North America, India, Russia, Israel)
• Eminella Özdikmen, 2007 (Argentina) - renamed from Catuna Mello-Leitão, 1940
• Fageia Mello-Leitão, 1929 (Brazil)
• Gephyrellula Strand, 1932 (Brazil)
• Gephyrina Simon, 1895 (South America)
• Gephyrota Strand, 1932 (Africa, Asia)
• Hirriusa Strand, 1932 (Africa)
• Metacleocnemis Mello-Leitão, 1929 (Brazil)
• Paracleocnemis Schiapelli & Gerschman, 1942 (Argentina)
• Paratibellus Simon, 1932 (Europe to Central Asia)
• Petrichus Simon, 1886 (South America)
• Philodromops Mello-Leitão, 1943 (Brazil)
• Philodromus Walckenaer, 1826 (236 species; Holarctic, America, Australia, Africa, southern Asia)
• Procleocnemis Mello-Leitão, 1929 (Brazil)
• Suemus Simon, 1895 (Africa, Vietnam)
• Thanatus C. L. Koch, 1837 (Africa, Holarctic, South America)
• Tibellus Simon, 1875 (Africa, America, Holarctic, southern Asia)
• Tibitanus Simon, 1907 (Africa)
• Vacchellia Caporiacco, 1935 (Karakorum)

• Pselloninae

• Psellonus Simon, 1897 (India)
• Pseudopsellonus Balogh, 1936 (New Guinea)
• Senoculifer Balogh, 1936 (New Guinea)

• incertae sedis

• Euthanatus Petrunkevitch, 1950 † (fossil)
• Filiolella Petrunkevitch, 1955 † (fossil)
• Medela Petrunkevitch, 1942 † (fossil)

Gallery

• 

  Running crab spider.

See also

• List of Philodromidae species
• Spider families