Schmitzia sanctae-crucis sp. nov. (Calosiphoniaceae, Rhodophyta) and a novel nutritive development to aid in zygote nucleus amplification

Abstract

The taxonomic history of a soft, gelatinous red alga collected a little more than 100 years ago by W. G. Farlow at Cooper's Island, Bermuda, and again in 1985 at St Croix, U. S. Virgin Islands, is clarified. In 1912, Setchell referred some of Farlow's collection to Calosiphonia verticillifera (J. Agardh) Setchell which, on the basis of vegetative and reproductive morphology, are similar to our specimens from St Croix. Farlow's plants and the St Croix plants are recognized as one species, Schmitzia sanctae-crucis sp. nov. The vegetative morphology and sexual reproductive biology of this new species are illustrated. Sexual reproduction includes a novel method of supplying nourishment for the development of the carposphorophyte. A fertilized carpogonium may form up to four, septate and branched connecting filaments, each of which may fuse with an auxiliary cell, or one or more may fuse with nearby cortical branch cells, followed by subsequent branching to form a plexus of cortical filament-connecting filament fusions and connecting filaments that ultimately fuse with other cortical cells and auxiliary cells. This unusual post-fertilization phenomenon is not reported for the European S. neapolitana or S. hiscockiana. The gonimoblasts of Schmitzia originate directly from the connecting filament close to the point of this filament's fusion with a tubular process produced by the auxiliary cell. Such an origin of the gonimoblast from a connecting filamentis in contrast to the situation that occurs in Calosiphonia, where gonimoblasts develop directly from an auxiliary cell. It is concluded that Calosiphonia vermicularis (J. Agardh) Schmitzia as described by Okamura from Japan belongs to the genus Schmitzia because its gonimoblasts originate from connecting filaments.