Pavlova Butcher emend. Véron

Fig. 13

Included species

Pavlova gyrans Butcher 1952: pl. II, figs 35–38.

Chrysocapsa granifera Mack 1954: fig. 1. – Chrysocapsella granifera (Mack) Bourrelly 1957. – Pavlova granifera (Mack) Green 1973.

Pavlova pinguis Green 1967: fig. 1.

Emended description

Motile, free-swimming, highly metabolic cells with two unequal flagella and a short haptonema. Longer anterior flagellum with fine non-tubular hairs and tiny knob-scales (i.e., ʻdense bodiesʼ), which may or may not be present on the cell body. A pit or canal penetrating the cell near the long anterior flagellum. Chloroplast with a central, large and campylotropous pyrenoid bulging posteriorly and a conspicuous E located on the inner side near the flagellar bases. Non-motile cells in unstratified mucilage with incomplete appendages.

Key to the genera

The hierarchisation of cytomorphological criteria to provide a simple key to the identification of taxa is not always easy. In his proposal based on characters of the motile cells, Green (1980) used the morphology of the flagella and haptonema as the first criterion, followed by the characters of the stigma, knob-scales, metabolism and the general shape of the cells. It appears today that the combined characters of the pyrenoid, the stigma and the thylakoids are sufficient to discriminate between the four genera (Fig. 14).