This video of the male Habronattus amicus shows a spider collected by Ryan Kaldari. Kaldari’s original images and notes at the BugGuide link below. H. amicus is one of three species in the amicus group. Ranging from Pacific beaches to altitudes of 3000 plus meters in the Sierra Nevadas and Cascades, this species is known for its variably forms as well as the hairy aspect to the dorsal abdomen. Several varieties are illustrated in Hedin’s and Maddison’s website of California and Baja Habronattus. The coastal form, an impressive example of adaptation to sandy beaches, is illustrated in Marshal Hedin’s photograph (see “Habitat Image”) of H. amicus taken at Morro Bay, California.
Hedin and Maddison, 2009; Griswold, 1987
Kaldari, BugGuide