The intertidal spiders (family Desidae) live in a very unusual location  between the tides. Once thought to be limited to the Southern Hemisphere, members of this family in the genus Paratheuma were discovered in northern Sonora and the Florida Keys during the last half of the 20th Century. The family has been reevaluated in recent years and now includes inland genera and species as well. Members of the genus Paratheuma commonly live in barnacle shells,...
