Microcina leei

Lee's Micro-blind Harvestman

Family: Phalangodidae · Class: Arachnida · Order: Opiliones

Conservation status: G1 S1

Lee's Micro-blind Harvestman is a small arachnid belonging to the order Opiliones, suborder Laniatores, family Phalangodidae. This diminutive harvestman is distinguished from spiders by its fused body segments and lack of silk production. As indicated by its common name, the species exhibits reduced or absent eyes, an adaptation to its specialized microhabitat beneath rocks and in soil crevices. This species is endemic to the San Francisco Bay Area of California, where it occurs exclusively on serpentine soils. According to the U.S. Fish and Wildlife Service Recovery Plan for Serpentine Soil Species, Lee's Micro-blind Harvestman is restricted to serpentine soil grasslands within the greater San Francisco Bay Area and adjacent foothills and valleys. The species is found alongside other endemic harvestmen in the genera Microcina and Calicina that are similarly restricted to this unique geological substrate. Lee's Micro-blind Harvestman inhabits dry, nutrient-poor serpentine soil grasslands, a specialized ecosystem characterized by soils derived from serpentine rock outcrops. These soils contain high levels of magnesium and heavy metals while being deficient in essential plant nutrients like nitrogen and phosphorus. The species is found exclusively on the undersides of moist rocks situated within these serpentine grasslands, occupying cryptic microhabitats that provide necessary moisture and protection from desiccation. Little is documented about the specific behavior and ecology of Lee's Micro-blind Harvestman. Like other harvestmen, the species likely feeds on small invertebrates, detritus, and organic matter within its rock crevice habitat. The reduced eyes suggest adaptation to a life spent primarily in dark, humid microenvironments beneath stones. Reproduction and life cycle details have not been well studied for this species, though harvestmen typically undergo direct development without a larval stage. Lee's Micro-blind Harvestman is ranked G1 S1, indicating it is critically imperiled both globally and within California, and is on CDFW's Special Animals List. The species faces significant conservation challenges due to its extremely restricted range and specialized habitat requirements. According to the USFWS Recovery Plan, conversion of habitat to urban and industrial uses has extirpated serpentine soil species from the majority of their historic ranges. The remaining natural serpentine soil grasslands continue to face pressure from development, altered fire regimes, and invasion by non-native plants that can modify soil chemistry and vegetation structure. As of December 2025, the species does not have federal listing status under the Endangered Species Act, though it is recognized as a species of conservation concern. The fragmented nature of remaining serpentine grasslands and the species' limited dispersal ability make population connectivity and long-term viability significant concerns. Conservation efforts focus on protecting remaining serpentine grassland habitats and managing them to maintain the specific soil and microhabitat conditions required by this and other endemic species.

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, and more.