Saltonia

Saltonia is distinguished by its cribellate silk production and a colulus similar to that of intertidal spiders in the family Desidae (Paratheuma and Desis). The genus is monotypic, so identification at the species level requires distinguishing S. incerta from other small sheet-web weaving spiders in arid southwestern habitats. Genetic analysis confirms close relationship to Paratheuma and the fully aquatic Argyroneta aquatica.

Salt crusts of intermittent or dry lakes, streams, and rivers in the desert southwest of North America. Found specifically on the underside of moderate to thick salt crusts on dry lakebeds and along the salty shores of wet or intermittent waterways. All known localities are associated with salt springs, salt water, or salt marshes in arid environments.

Southwestern North America: California (Mojave Desert including Death Valley, China Lake, Soda Dry Lake, Bristol Lake, Cadiz Lake, Dale Lake, Danby Lake; Salton Sea area), northern Baja California (Laguna Salada, El Doctór), and New Mexico (White Sands Missile Range, White Sands National Monument—Lake Otero, Lake Lucero). Populations occur across six drainage basins: Amargosa River, Owens River, Mojave River, Bristol drainage, Colorado River, and ancestral Rio Grande (Lake Otero).

All collected specimens have been found during March and April.

Builds tiny sheet webs on the underside of salt crusts. Has been observed cruising on the salt crust surface. Whether the species exhibits aerial dispersal (ballooning) remains unknown.

Serves as an indicator species for past environmental changes due to highly specific habitat requirements. Genetic evidence indicates that desert salt flats functioned as refugia for this terrestrial species during the aridification of the American southwest following Pleistocene glaciopluvial cycles. Strong population structure with minimal migration suggests long-term persistence in isolated habitat patches.

Once considered extinct, the species was rediscovered in the 1990s. Its restricted distribution and specific habitat requirements make it vulnerable to habitat alteration from water management practices, salt flat disturbance, and climate change in arid southwestern North America.

• ParatheumaShares similar colulus structure and is genetically closely related; both occupy intertidal or saline-associated habitats
• DesisShares similar colulus structure with intertidal zone representatives of this genus
• Argyroneta aquaticaGenetically closely related despite being fully aquatic; represents a divergent ecological specialization within the same lineage

• spider
• cribellate
• monotypic
• relict
• hypersaline
• desert
• salt flat
• rare

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Desert salt flats as oases for the spider Saltonia incerta Banks (Araneae: Dictynidae)