ibclogo XVI International Botanical Congess


Abstract Number: 4547
Session = 7.1.2


CHRYSOPHYTES AS ASSEMBLAGES OF POLYPHYLETIC ORIGINS


Isao Inouye, Biol. Sci. Univ. Tsukuba, Ibaraki 305 Japan.


Ultrastructural and molecular studies have revealed heterogeneity of the Chrysophyceae s.l. Some groups have been separated from the class at divison (Haptophyta) or class level (Synurophyceae, Dictyochophyceae, Pelagophyceae, Phaeothamniophyceae), and probably several others should be removed. Although phylogenetic positions of heterokont algae are still unsolved, the Chrysophyceae s.s. often appears as a derived taxon in the published phylogenetic trees. Ultrastructural comparisons between heterokont algae with colorless heterokonts which probably diverged earlier than heterokont algae may provide information to consider evolution of morphological characters. For example, the structure of the flagellar root 3 (R3) is conservative and R3-associated feeding behavior is widely distributed in heterokonts, suggesting that these are very old features butstill retained in the Chrysophyceae s.s.


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