A day and a night in the life of a cleft-foot clam: Protovirgularia-Lockeia-Lophoctenium

A remarkable specimen of a compound trace fossil in Pennsylvanian sandstone comprises three very different ichnotaxa in conjunction: Protovirgularia d ichotoma, Lockeia siliquaria and Lophoctenium isp. The combined activities represented by these ichnotaxa reflect the locomotion, resting and feeding behavior of a cleft-foot, protobranch clam (bivalve) that burrowed through the sediment, paused five times to deposit-feed, and then burrowed on to a new location, possibly as a reaction to a depositional event. It is estimat ed that the complete trace fossil was made in 24 hours or less. The three i chnotaxa also provide morphologic details of the bivalve's shell and soft p arts (foot and labial palps).