Description of Hibberdia
provided by BioPedia
Hibberdialean stramenopiles, free-swimming single-celled flagellate stage alternating with a palmelloid stage consisting of non-swimming flagellate cells within a colonial gel; motile cells with a single emergent anterior flagellum, 1-2 parietal chloroplasts, one of which containing an eyespot closely associated with a swollen region of the very short second flagellum; basal apparatus with three microtubular roots (R1, R2 and R4), and a rhizoplast (system II fibre); absence of R3 root and lack of food vacuoles suggest phagocytosis does not occur; contractile vacuole single, anterior; chrysolaminaran vacuole posterior; light harvesting pigments include fucoxanthin and antheraxanthin (the latter is unique, see Alberte & Andersen 1986); cell division both in free-swimming and colonial state; nuclear envelope mostly intact during mitosis, with polar fenestrae at metaphase; sexual reproduction and stomatocysts unknown; type species: Hibberdia magna (Belcher 1974) Andersen 1989.
