This is a relatively rare member of the marine (Essex) portion of the Mazon Creek deposit.
Hesslerella shermani looks to the casual observer to be some type of shrimp.
It is actually a marine isopod related to modern day pill bugs.
One of the main features that differentiate it from a shrimp is that it lacks a carapace.
Other distinguishing characteristics are a rounded head with large eyes. The legs are also similar in length.
Hesslerella is one of the smallest crustaceans