The delta smelt is an endangered slender-bodied smelt, about 5 to 7 cm long, in the family Osmeridae. Endemic to the upper Sacramento-San Joaquin Estuary of California, it mainly inhabits the freshwater-saltwater mixing zone of the estuary, except during its spawning season, when it migrates upstream to fresh water following winter "first flush" flow events. It functions as an indicator species for the overall health of the Delta's ecosystem.
The Kanab ambersnail, formerly classified as Oxyloma haydeni kanabense or Oxyloma kanabense, is a small, air-breathing land snail belonging to the the family Succineidae, the ambersnails. This terrestrial pulmonate gastropod mollusc was previously considered a critically endangered subspecies or species. In 2013, a scientific investigations report by the United States Geological Survey concluded that the Kanab ambersnail is not a genetically distinct species. In June 2021, the Fish and Wildlife Service removed the Kanab ambersnail from the United States Fish and Wildlife Service list of endangered mammals and birds and classified it with other common ambersnails within the same taxa, officially negating its status as a distinct subspecies.
Lymnaeidae, common name the pond snails, is a taxonomic family of small to large air-breathing freshwater snails, aquatic pulmonate gastropod mollusks, that belong to the clade Hygrophila.
The Tumbling Creek cavesnail is a species of freshwater cave snail with gills and an operculum, an aquatic gastropod mollusk in the family Amnicolidae.
Assiminea pecos is a rare species of snail in the family Assimineidae known by the common name Pecos assiminea. It is native to New Mexico and Texas in the United States. Specimens known from Mexico are now treated as members of a separate species, Assiminea cienegensis. The Pecos assiminea was federally listed as an endangered species of the United States in 2005.
The lacy elimia also known as the lacey elimia, scientific name Elimia crenatella, is a species of freshwater snail with a gill and an operculum, an aquatic gastropod mollusk in the family Pleuroceridae.
Newcomb's snail is a species of air-breathing freshwater snail, a gastropod mollusk in the family Lymnaeidae. This species is endemic to Hawaii, in the United States. Its natural habitat is rivers. It is threatened by habitat loss.
Hamiota perovalis, the orangenacre mucket or orange-nacre mucket, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels.
The cylindrical lioplax, scientific name Lioplax cyclostomaformis, is a species of freshwater snail with gills and an operculum, an aquatic gastropod mollusk in the family Viviparidae.
The Snake River physa snail, scientific name Physella natricina, is a species of freshwater snail, an aquatic gastropod mollusk in the family Physidae. This species is endemic to Idaho in the United States.
The San Bernardino springsnail is an endangered species of freshwater snail in the family Hydrobiidae. This species is endemic to a small number of springs in the USA and northern Mexico.
Marstonia ogmorhaphe, common names the royal marstonia or royal springsnail, is a minute species of freshwater snail, an aquatic gastropod mollusk or micromollusk in the family Hydrobiidae, the mud snails. This species is endemic to Tennessee in the United States, where it occurs in two streams in Marion County. It is a federally listed endangered species of the United States.
Rhodacmea elatior, the domed ancylid, is a species of small freshwater snail or limpet, an aquatic gastropod mollusk in the family Planorbidae, the ram's horn snails and their allies.
Tryonia alamosae, common name the Alamosa springsnail, is a species of small freshwater snail, an aquatic prosobranch gastropod mollusk in the family Hydrobiidae.
The Utah roundmouth snail, also known as the Utah valvata or desert valvata, scientific name Valvata utahensis, is a species of freshwater snail with a gill and an operculum, an aquatic gastropod mollusc in the family Valvatidae, the valve snails.
Lirceus usdagalun is a rare species of crustacean known by the common name Lee County cave isopod. It is endemic to Virginia in the United States, where it is known from a single network of karst cave systems in Lee County. It is threatened by a number of processes. It is a federally listed endangered species of the United States, and is assessed as "endangered" by the International Union for Conservation of Nature.
Lithophragma maximum, known by the common name San Clemente Island woodland star, is a rare species of flowering plant in the saxifrage family. It is endemic to San Clemente Island, one of the eight Channel Islands of California. It is known from only about four kilometers of rocky coastal cliffs on the edge of the island. The plant was thought to be extinct until a few specimens were rediscovered in 1979. Only 200 individuals were tallied in a 1996 survey. In 1997 the plant was listed as an endangered species on the federal level.
Gratiola amphiantha is a rare species of flowering plant known by the common names little amphianthus, pool sprite and snorkelwort. It was previously the only species in the monotypic genus Amphianthus, but it was moved to genus Gratiola after genetic analysis in 2008. It is native to the Piedmont region of the southeastern United States, with a center of distribution in Georgia. It occurs in Alabama and South Carolina as well. It is limited to granite outcrops, a high-biodiversity habitat type that is threatened by activities such as quarrying, off-road vehicles, and trash and debris dumping. It is a federally listed threatened species.
Stygoparnus is a monotypic genus of beetles containing the single species Stygoparnus comalensis, which is known by the common name Comal Springs dryopid beetle. This rare beetle is endemic to Texas in the United States, where it is known from two springs. It is a federally listed endangered species of the United States.
