Isopod-infected prosoponids from the Upper Jurassic of Poland

Abstract

Some of the prosoponids, i.e. small brachyuran decapods of the family Prosopidae von Meyer, occurring In Upper Jurassic (Oxfordian) deposits of Poland bear their carapaces modified by the presence of isopods infecting the branchial cavities. The analysis of the life activity of the isopods and of the reaction of the prosoponids against the intruders leads to a conclusion that the prosoponid/isopod relationship is of the commensal character, and there is no evidence of the previously postulated parasitism.