OutdoorNebraska

36 Fatmucket, Lampsilis siliquoidea Description: The Fatmucket is a medium sized shell up to 120-130mm. The shell is fairly thick and heavy. The anterior end in both sexes is rounded. In males, the posterior end is slightly broader than the anterior end and bluntly pointed. The posterior of the shell of mature females is broader than the anterior end, very inflated and squared. The exterior is tan or brown and smooth. Younger individuals may have radiating green rays on the posterior end. The beaks are raised slightly above the dorsal edge and the sculpture consists of several fine V- shaped wavy ridges. Similar species: The Fatmucket is similar to the Yellow Sandshell in overall shape and shell thickness. The Yellow Sandshell is more elongated and their adults are yellow where the Fatmucket is brown. Conservation status: G5, N5, S1/SH. A live specimen and several dead shell in good condition have been collected from the Big Blue River. The current status is not known but they may be extirpated or nearly so. Hosts: Bluegill, bluntnose minnow, green sunfish, largemouth bass, pumpkinseed, rock bass, sand shiner, smallmouth bass, white sucker. Habitats used: Lakes and small to medium-sized streams in mud, sand, or gravel (Cummings and Mayer 1992). Large rivers and lakes in river flowages in soft or coarse substrate (Seitman 2003). Almost any substrate in moderate to slowly moving water. May be found in mud substrates of lakes (Oesch 1995). Quiet to slowly moving water with a mud bottom, avoiding riffles (Parmalee and Bogan 1998). Nearly all substrates and flow regimes from extreme headwaters to ponds, lakes, and rivers. Rare in largest rivers (Watters et.al. 2009). Distribution: The Mississippi River basin except for Tennessee and Cumberland River drainages. New York to Minnesota south to Arkansas. Great Lakes tributaries and south- central Canada. Collection notes: This species is mostly found as relict shell in the Nemaha and Big Blue River basins. Also has been found as relicts in lower Elkhorn and Logan Creek. One collection of dead shell below Gavins Point Dam. A single live was found in lower Big Blue River. The archeological records show that they were once widely distributed. Comments: This was once a common species that has severely declined for unknown reasons. Note that the Big Blue was heavily fragmented by power dams in the late 1800's and the Nemaha (and Logan Creek) were channelized in the early 1900's.

• Cover