Worms Crawl In, Poop Comes Out

Composition: 
Location: 
Thompson Butte Caputa , SD
United States
South Dakota US
Dimensions: 
1mm x 0.5mm

Not only do we have the fossilized remains of a crab (Dakoticancer sp.), we have coprolites!  These tiny coprolite pellets are thought to have been left by segmented worms that fed on the little crab corpses. 

Source: Gale A. Bishop did a study of discussing this subject in a paper entitled,  "Pierre Feces: A Scatological Study of the Dakoticancer Assemblage, Pierre Shale (Upper Cretaceous) of South Dakota."  This doubly interesting little crab was one of those collected as part of that study.