A Paradise Jumping Spider (Habronattus sp.), photographed along the Elk Grove Creek Trail, just north of Arnie and Iris Zimbelman Park, in Elk Grove, CA. This was a small spider, measuring 5 or 6 mm long from its pedipalps to its spinnerets.
Note that the enlarged anterior median eyes, powerful forelegs, and stocky body of this spider indicate that it is one of the Jumping Spiders (family Salticidae). Also note that the third leg from the front is longer than the fourth leg; this trait, along with the striking patterns on this spider's body, indicate that it is one of the Paradise Jumping Spiders in the genus Habronattus.
I attempted to identify this spider to species, but I wasn't really able to find a good enough match. H. klauseri seemed to be the closest fit, as its body patterns and coloration were close to the individual in my photograph, and as research grade records for H. klauseri have been reported to iNaturalist in the same region where I found this individual (northern California). However, I was not able to find any photographic examples of H. klauseri with a red patch around the anterior median eyes, as is evident for the individual in my photograph, so I am not sure. H. schlingeri is also close, but it also seems to lack the red patch around the anterior median eyes, and in any case, its range is restricted to southern California
Hiding in a crack in the sidewalk