Woelkerlingia minuta gen. et sp nov from the Mediterranean Sea and a reassessment of the genus Lomathamnion, with the description of two new genera:: Hommersandiella gen. nov and Stegengaea gen. nov (Ceramiaceae, Rhodophyta)

The new genus Woelkerlingia, with the new species W. minuta (Ceramiaceae, Rhodophyta), is described from the Mediterranean Sea. This genus, belonging to the tribe Spermothamnieae, seems related to Lomathamnion (type species L. epicodii) from which it differs mainly in having terminal female fertile filaments with only the apical and subapical cells smaller than other vegetative cells, and terminal spermatangial heads with spermatangia produced directly by periaxial cells. Since the other two species of Lomathamnion (L. capense and L. humile) do not show the diagnostic characters of the genus and appear to be distinct from each other in main reproductive characters (except for only one periaxial cell produced by the subapical cell of the female fertile filament), two new genera, Stegengaea and Hommersandiella, are proposed to accommodate L. capense and L. humile, respectively.