A second species of Dotyophycus (Nemaliales, Rhodophyta) that emphasizes the distinctness of a diffuse gonimoblast

Abstract

The transfer of Liagoropsis yamadae Ohmi et Itono from southern Japan to Dotyophycus [D. yamadae comb. nov.] (Rhodophyta, Dermonemataceae) makes possible a comparison with D. pacificum, the type species, of carpogonial branches that are 8-17 cells long and of the structure of a diffuse gonimoblast. The diffuse gonimoblasts clearly show initials cut off from the lateral faces of each of the daughter cells of the fertilized carpogonium, starting the horizontal spread of the gonimoblast filaments, unlike the erect, compact gonimoblast filaments of Liagora or Nemalion. These diffuse cystocarps are more elaborate and larger than those of Cumagloia and Dermonema, and perhaps demonstrate another pathway by which these structures have evolved, since the carpogonial branches which precede them are modified vegetative filaments and those of Cumagloia and Dermonema are accessory branches. The length of the carpogonial branches and the diffuse gonimoblast exclude D. yamadae from Liagoropsis in which it was first placed.