Dumontia oregonensis

Hairy Water Flea

(c) Lou Wagstaffe, some rights reserved (CC BY) · licence

Family: Dumontiidae · Class: Branchiopoda · Order: Diplostraca

Conservation status: G1G3 S1

Dumontia oregonensis (Hairy Water Flea) is a California animal in the Dumontiidae family.

Dumontia oregonensis is a freshwater microcrustacean in the order Diplostraca (water fleas) and suborder Anomopoda. First described in 2003 by Santos-Flores and Dodsen, this species represents a morphologically unique lineage within Anomopoda and is believed to represent a previously unknown evolutionary branch. The species exhibits typical cladoceran body structure with a carapace enclosing the trunk and swimming appendages. Collected specimens have included both mature and immature females, though detailed morphological descriptions remain limited in available literature. Dumontia oregonensis has an extremely restricted range, known only from vernal pools in southern Oregon and northern California. The species was originally collected from two vernal pools at The Nature Conservancy's Agate Desert Preserve near Medford, Oregon, in January 1998 and March 2001. According to NatureServe, the species has since been documented from three temporary pools in the Medford area and at least one additional site in California, representing a total global range of fewer than five known locations. This species inhabits seasonal vernal pools, temporary wetland systems that fill with water during winter and spring rains and dry completely during summer months. These pools occur within the Agate Desert ecosystem, characterized by shallow depressions in clay hardpan soils that create impermeable basins. The vernal pool habitat supports a specialized community of endemic organisms adapted to the extreme seasonal fluctuations between inundation and complete desiccation. Dumontia oregonensis appears to be specifically adapted to these ephemeral aquatic conditions. As a cladoceran, Dumontia oregonensis likely exhibits typical water flea ecology, including filter-feeding behavior and reproduction through both sexual and asexual phases. Cladocerans generally feed on bacteria, algae, and organic particles suspended in the water column. The species' occurrence in vernal pools suggests adaptation to rapid population growth during wet periods and survival strategies for the dry season, though specific life history details have not been documented. The timing of collections in January and March indicates activity during the wet season when pools contain water. Dumontia oregonensis has a NatureServe global rank of G2, indicating the species is imperiled globally due to rarity and restricted range. This species is included on the California Department of Fish and Wildlife's Special Animals List. The California rank of S1 reflects its extreme rarity within the state. According to the U.S. Fish and Wildlife Service, this newly described species faces potential threats from habitat loss, making it a species of elevated conservation concern. The species' dependence on vernal pool habitat makes it vulnerable to agricultural conversion, urban development, and hydrological alterations that could eliminate or degrade these temporary wetlands. Recovery planning efforts for other vernal pool species in the Rogue and Illinois Valleys may provide indirect benefits for Dumontia oregonensis habitat conservation. The species' taxonomic distinctness and endemic status in vernal pools emphasize its conservation importance as a unique component of this threatened ecosystem.

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