UTC Clade

Viridiophytes: green plants

The UTC Clade is one of the two major lineages of green organisms (the other being streptophytes, = embryophytes + charophyceans). Originally two classes, the third class, Trebouxiphyceae, was erected following molecular genetic analysis. This split the famous genus Chlorella between two classes. Trebouxiphyceans are represented here by the Microthamniales and Chlorella vulgaris. Beyond this level, relationships with the Trebouxiophyceae are not well resolved. All motile members of the Ulvophyceae and Trebouxiophyceae share counter-clockwise displacement of the flagellar basal apparatus, but the Chlorophyceae display two different types (three if the exceptional Hafniomonas is counted). Thus, original hypotheses on UTC evolution placed trebouxiophyceans with the ulvophyceans. More recent molecular analyses suggest that the trebouxiophyceans are actually more closely related to chlorophyceans, implying that the radiation of the more variable chlorophycean basal apparatus structure may be a relatively recent event. Because green plants are thought to have colonised land from the oceans, the basal position of the Ulvophyceae in this clade is logical (most ulvophyceans are marine). The other two classes are primarily non-marine.

Indigenous or exotic to New Zealand.

NZ Flora Web Site Link to the Ngā Tipu o Aotearoa Database

Booton, G.C., Floyd, G.L., Fuerst, P.A. (1998) Origins and affinities of the filamentous green algal orders Chaetophorales and Oedogoniales based on 18S rRNA gene sequences. Journal of Phycology 34, 312–318.
Freidl, T., Zeltner, C. (1994) Assessing the relationships of some coccoid green lichen algae and the Microthamniales (Chlorophyta) with 18S ribosomal RNA gene sequence comparisons. Journal of Phycology, 30, 500–506.
Friedl, T. (1995) Inferring taxonomic positions and testing genus level assignments in coccoid green lichen algae: a phylogenetic analysis of 18S ribosomal RNA sequences from Dictyochloropsis reticulata and from members of the genus Myrmecia (Chlorophyta, Trebouxiophyceae cl. nov.). Journal of Phycology, 31, 632–639.
Huss, V.A.R., Frank, C., Hartmann, E.C., Hirmer, M., Kloboucek, A., Seidel, B.M., Wenzeler, P., Kessler, E. (1999) Biochemical taxonomy and molecular phylogeny of the genus Chlorella sensu lato (Chlorophyta). Journal of Phycology, 35, 587–598.
Krienitz, L., Ustinova, I., Friedl, T., Huss, V.A.R. (2001) Traditional generic concepts versus 18S rRNA gene phylogeny in the green algal family Selenastraceae (Chlorophyceae, Chlorophyta). Journal of Phycology, 37, 852–865.
Mishler, B.D., Lewis, L.A., Buchheim, M.A., Renzaglia, K.S., Garbary, D.J., Delwiche, C.F., Zechman, F.W., Kantz, T.S., Chapman, R.L. (1994) Phylogenetic relationships of the green algae and bryophytes. Annals of the Missouri Botanical Garden, 81, 451–483.
Pröschold, T., Marin, B., Schlösser, U.G., Melkonian, M. (2001) Molecular phylogeny and taxonomic revision of Chlamydomonas (Chlorophyta). I. Emendation of Chlamydomonas Ehrenberg and Chloromonas Gobi, and description of Oogochlamys gen. nov. and Lobochlamys gen. nov. Protist, 152, 265–300.
Phil Novis PhycologistPhycologist
Last updated: 05-Mar-2013