Freshwater Mussels of Florida

Lasmigona subviridis

Species of Hypothetical Occurrence 398 slightly biangulate; posterior slope flat to slightly concave, often with few fine wrinkles; umbo broad, inflated, elevated well above hinge line; umbo sculpture concentric ridges, with slight indentation on ventral margin; umbo cavity wide, moderately deep. teeth: pseudocardinal teeth compressed, 2 teeth in left valve, roughly parallel to dorsal margin, anterior tooth considerably larger, 1 tooth in right valve, usually with well-developed lamellar accessory denticle anteriorly along shell margin; lateral teeth thin to moderately thick, straight to slightly curved, 2 in left valve, 1 in right valve; interdentum moderately long, narrow. Nacre: white to bluish white. Periostracum: typically shiny; yellowish, with thin, irregularly spaced, green rays. General Distribution Lampsilis binominata occurs in Chattahoochee River in Alabama and Georgia, and Flint River and its large headwater tributary, Line Creek, in Georgia. Habitat Based on historical museum records, it appears Lampsilis binominata occurred in large creeks and rivers with moderate to swift current in substrates of sand and gravel (Williams et al. 2008). Reasons for Inclusion Although collection sites in Alabama and Georgia are more than 100 air miles from Florida, habitat in Apalachicola River below Jim Woodruff Lock and Dam are similar to sites where Lampsilis binominata has been found. Further, archaeological specimens that resemble the species are known from Flint River in Georgia. Lasmigona subviridis (Conrad 1835) Green Floater Lasmigona subviridis – Length 48 mm, UMMZ 23324. Chattahoochee River, Columbus, Muscogee County, Georgia.© Richard T. Bryant. Description Size: length to 63 mm. Shell: thin; smooth; moderately compressed, width 35%–45% of length; outline elliptical; anterior margin rounded; posterior margin rounded, may be slightly truncate; Species of Hypothetical Occurrence 399 dorsal margin straight to slightly convex; ventral margin straight to slightly convex; posterior ridge rounded, may be weakly biangulate posterioventrally; posterior slope moderately steep, flat to slightly concave; umbo broad, elevated slightly above hinge line; umbo sculpture thick, double-looped, nodulous ridges; umbo cavity moderately wide, shallow. teeth: pseudocardinal teeth low, rudimentary, compressed, typically 2 teeth in left valve, 1 tooth in right valve, interdental projection in left valve poorly developed, confluent with pseudocardinal tooth; lateral teeth thin, straight, 2 teeth in left valve, 1 in right valve; interdentum moderately long, very narrow, interdentum of right valve may be divided by depression that accommodates interdental projection of opposing valve. Nacre: white to bluish white. Periostracum: shiny to dull; green, yellowish olive to brown, usually with green rays. General Distribution Lasmigona subviridis occurs along the Atlantic Coast in basins from the St. Lawrence River south to Cape Fear River in North Carolina. There is also an isolated population in Savannah River basin (Fuller 1971) and archaeological material has been recovered from a midden in the Altamaha River basin in Georgia (A.E. Bogan, personal communication). It also occurs in interior drainages in North Carolina, Virginia, and West Virginia (Clarke 1985; Pinder et al. 2003), and east Tennessee and west North Carolina (Parmalee and Bogan 1998). In eastern Gulf Coast rivers, it was found only in Apalachicola basin in Alabama and Georgia (Brim Box and Williams 2000). Habitat Lasmigona subviridis inhabits creeks and rivers in slow current in mud, sand, and gravel substrates. Reasons for Inclusion Habitats of Lasmigona subviridis, side channels of rivers and large creeks in slow currents, exist in Apalachicola River. The nearest localities for L. subviridis in Alabama and Georgia are from Chattahoochee and Flint Rivers, and are more than 100 air miles north of Florida. ...