Stars from the Silurian sky. Echinoderm holdfasts from the Carnic Alps (Austria)

A small collection of echinoderm holdfasts from the Ludlow Cardiola Formation of the Carnic Alps (Austria) contains a wide range of morphologies as a response of environmental adaptation. In general, the holdfasts have a globous and massive dome-like profile with several processes arranged in a sub-radial disposition, so to create a sort of ‘star-like’ outline. A small central depression is common but not present on all specimens. The distinctive holdfasts are preserved in an iron-rich phase, documenting a substitution that has also affected other non-echinoderm calcareous material.