Collemopsidium halodytes Cf. forme sur Patella.
This taxon is characterized by its occurrence on the shells of Limpets. The perithecia with a diameter of 0.5-1 mm are deeply sunk into the substrate and relatively not protruding, numerous pycnidia in the form of large black dots on the surface of the substrate. Spores according to our measurements: (17) 18-22 x (7) 8-10 µm. Almost always with Collemopsidium foveolatum forme sur Patelle..
N.B. Difficult to classify because of its characters crossed with other species in particular with Collemopsidium ostrearum by the large size of its perithecia but they are not very prominent and its spores are smaller as in Collemopsidium halodytes..