Taxonomy and ultrastructure of five species of Tetraselmis (Prasinophyceae) isolated from China seas

Comparative ultrastructural investigations on twenty-three isolates of Tetraselmis from the South China Sea, East China Sea and Huanghai Sea, have revealed that these isolates belong to:(1) Tetraselmis chui Butcher; (2) T. cordiformis (H. J. Carter) Stein; (3) T. helgolandica Kylin; (4) T. suecica (Kylin) Butcher; (5) T. guangdongensis sp. nov. Except T. helgolandica,the others are new records in China. T. guangdongensis sp. nov. is a new species. Its external and anatomical features closely resemble those of T. impellucida McLachlan et Parke. As in that species the pyrenoid is penetrated from many directions by cytoplasmic channels delimited by a double membrane.The protoplast withdraws from the apical portion of the theca, that portion which overlaid the trough inverts and pops out in the form of a teat. But unlike that species a starch sheath is present; pyrenoid matrix is surrounded by thylakoids which intervenes between the matrix and the starch sheath surrounding pyrenoid; the theca is stratified.