Error vacuo, Detecting Structures in Poorly Calcified Jurassic Dasycladales

Several Jurassic dasycladalean genera (e.g. Pseudoclypeina, Palaeodasycladus, Eodasycladus, Chinianella and Cylindroporella) display a complex structure which, owing to a deficit of calcification, is difficult to interpret. This lack of calcification causes a loss of certain soft algal structures and complicates the work of the specialist responsible for interpreting the algal anatomy as well as the corresponding position in the systematics. A key of interpretation is given, and case histories are discussed.