This is a mature male Aphonopelma eutylenum.

Fall in Anza-Borrego Desert State Park is mating season for these tarantulas. This is the time they are wandering around the lower parts of the desert. There are 3 species of tarantula in Anza-Borrego Desert State Park. The ‘reversum’ tarantula spiders are black. ┬áThose will only be found in the hills and mountains (higher elevation) areas of Anza-Borrego.