New taxa of the Porphyridiophyceae (Rhodophyta): Timspurckia oligopyrenoides gen. et sp. nov. and Erythrolobus madagascarensis sp. nov.

Two new marine unicellular red algae are described: Timspurckia oligopyrenoides gen. et sp. nov. isolated from southeastern Australia and Erythrolobus madagascarensis sp. nov. isolated from Madagascar. Timspurckia oligopyrenoides cells are spherical, 7-11 mu m in diameter, greyish red to reddish brown and surrounded by a conspicuous fibrillar matrix about 2 mu m thick. Cells exhibit positive phototaxis. In the single chloroplast the lobes extend from several pyrenoids to occupy most of the cell. A peripheral thylakoid is absent. The pyrenoid matrices are filled with tubular thylakoids and are usually surrounded by starch sheaths in the adjacent cytoplasm. The nucleus is peripheral with a nucleolus appressed to the nuclear envelope usually closest to the cell center. Golgi bodies are associated with mitochondria usually at the cell periphery. Erythrolobus madagascarensis cells are spherical, 5-8 mu m in diameter, greyish red to reddish brown and surrounded by a thin conspicuous fibrillar sheath. Cells exhibit positive phototaxis. Each cell has a single chloroplast with several lobes extending from an eccentric pyrenoid forming a complex parietal layer. A peripheral thylakoid is absent. The pyrenoid matrix is filled with tubular thylakoids. and a starch sheath is visible in the adjacent cytoplasm. The nucleus is eccentric and has a central nucleolus. Golgi bodies are associated with mitochondria usually at the cell periphery. Numerous conspicuous, electron-transparent, fibrous vesicles are always present in the cells. The sequence divergences of psaA and psbA genes and phylogeny support that E. madagascarensis sp. nov. and T oligopyrenoides gen. et sp. nov. are newly uncovered natural entities within the class Porphyridiophyceae along with Erythrolobus coxiae, Porphyrithum spp. and Flintiella sanguinaria. The low-molecular-weight carbohydrates (LMWCs) floridoside, digeneaside and trehalose are present in both taxa. Thus, three independent features - ultrastructural characters, plastid gene sequences and LMWC patterns - support the suggested phylogeny and taxonomy of these red algae.