Ceramium cormacii sp. nov. (Ceramiaceae, Rhodophyta), a new Mediterranean species epizoic on loggerhead sea turtles (Caretta caretta)

Ceramium cormacii is newly described based on both vegetative and tetrasporangial features of specimens growingon loggerhead sea turtles ( Caretta caretta ) from theMediterranean Sea. The new species is characterised by bothprostrate and erect axes (9 – 12 mm high), dichotomouslyto pseudo-dichotomously branched with apices straight orslightly incurved, attached to the substratum by unicellularrhizoids often terminating in multicellular pads, incompletecortication formed by one to three rows of acropetalcells, fi ve to six periaxial cells, and tetrahedral tetrasporangiaproduced by periaxial cells, strongly protruding andpartially involucrated.