Alabama Spike Elliptio arca. Restricted to Mobile Basin. Apparently imperiled through-out, except in Sipsey River. May be found in riffles or pools. HIGHEST CONSERVATION CONCERN.

Delicate Spike Elliptio arctata. Uncommon. Widespread but uncommon in Mobile Basin. Some confusion as to the taxonomic status of a similar form in the Gulf Coast systems. Usually encountered in areas with at least some current. Often found under large rocks. HIGHEST CONSERVATION CONCERN.

Chipola Slabshell Elliptio chipolaensis. Extirpated. In Alabama, known only from a single record from Howard’s Mill Creek, Houston County, in the Chattahoochee River system. Also records from other portions of the Apalachicola Basin in Georgia and Florida. Occurs in muddy sand in moderate current. Listed as threatened by the U.S. Fish and Wildlife Service.

Eastern Elliptio Elliptio complanata. Common. Found only in headwaters of Chipola River and tributaries of Chattahoochee River. Occurs in a variety of habitats. Low Conservation Concern.

Elephantear Elliptio crassidens. Abundant in many areas, but possibly declining in Mobile Basin and Gulf Coast drainages. Found throughout Alabama, except in Choctawhatchee River system. The dominant species in many areas, primarily in riverine habitats. Lowest Conservation Concern.

Spike Elliptio dilatata. Rare. Limited to Tennessee River system. Remnant populations are found in riverine areas downstream of Wilson and Guntersville dams. Restricted to lotic habitats. HIGHEST CONSERVATION CONCERN.

Brother Spike Elliptio fraterna. Extirpated. In Alabama, known from a single Chattahoochee River record from Russell County. Also records from other portions of the Apalachicola Basin in Georgia and Florida. EXTIRPATED.

Variable Spike Elliptio icterina. Common. Restricted to Gulf Coast systems. Taxonomic status uncertain. Possible species complex, but may be a distinct species. Part of a widely distributed complex of lanceolate Elliptio that occurs from southern Alabama throughout much of the Atlantic coast. May occur in current or sluggish areas. Lowest Conservation Concern.

Fluted Elephantear Elliptio mcmichaeli. Locally common, but declining. Apparently endemic to, and now restricted to, the lower reaches of the Choctawhatchee River system. Further taxonomic work may reveal similar forms in adjacent drainages belong to this species. Usually found in habitats with at least some current. HIGHEST CONSERVATION CONCERN.

Winged Spike Elliptio nigella. Extinct. Endemic to Apalachicola Basin. Known from a few Alabama records. Last reportedly collected in 1958. EXTINCT.

Inflated Spike Elliptio purpurella. Rare. Endemic to Apalachicola Basin. Historically found in Chattahoochee and Chipola river systems. Possibly Remnant populations are found in Big Creek, Houston County. Usually found in sand or limestone substrata. HIGHEST CONSERVATION CONCERN.