Error vacuo, detecting structures in poorly calcified Jurassic dasycladales

Several Jurassic dasycladalean genera (e.g. Pseudoclypeina, Palaeodasycladus, Eodasycladus, Chinianella and Cylindroporella) show a complex structure which is made more difficult to interpret by a deficiency of calcification. This lack of calcification delates part of the original structure and complicates the work of the specialist in interpreting the algal anatomy and assigning the right systematical status. A key of interpretation is given and case histories are discussed.