Hi, I have found a place .. there is a Czech Cretaceous basin and there is an abundant fossil bivalve Innoceramus - But several species ( Inoceramus lamarcki (PARKINSON), Inoceramus cuvieri SOWERBY, Inoceramus inaequivalvis (GÜMBEL) ) and I do not know what key to follow in their determination. Please advise, or I would like to ask what kind of photo is it?