FAWNSFOOT

The fawnsfoot (Truncilla donaciformis) is a small freshwater mussel that can anchor itself to rocks with a byssal thread.  The byssal thread is a bunch of filaments secreted by the mussel.  It is mostly collagen with a tendon-like structure.  The byssal thread likely keeps this small mussel from being washed downstream.  Like other mussels, the fawnsfoot spends part of its lifecycle attached to a fish host.  In this case, the fish host is the freshwater drum.  Ironically, the freshwater drum feeds on small mussels.