LOROXANTHIN, A PHYLOGENETICALLY USEFUL CHARACTER IN CHLAMYDOMONAS ANDOTHER CHLOROPHYCEAN FLAGELLATES

The distribution of loroxanthin in chlorophycean flagellates is consis tent with their phylogeny as inferred from molecular and organismal ch aracters. Although polarity of this character cannot yet be determined , if the absence of loroxanthin is plesiomorphic for chlorophycean fla gellates, the presence of loroxanthin defines a clade that includes th e Euchlamydomonas morphological group, two other species of Chlamydomo nas, C, asymmetrica and C. oblonga, and Gonium pectorale. A subsequent reversal to loroxanthin absence is apomorphic for the more complex vo lvocacean taxa. These results suggest that loroxanthin distribution wi ll be useful for resolving phylogenetic questions in green algae.