Krienitz, Lothar; Bock, Christina; Nozaki, Hisayoshi; Wolf, Matthias:

SSU rRNA gene phylogeny of morphospecies affiliated to the bioassay alga "Selenastrum capricornutum" recovered the polyphyletic origin of crescent-shaped chlorophyta

In: Journal of phycology, Jg. 47 (2011) ; Nr. 4, S. 880–893
ISSN: 1529-8817, 0022-3646
Zeitschriftenaufsatz / Fach: Biologie
Fakultät für Biologie » Allgemeine Botanik
Abstract:
The generic concept of coccoid green algae exhibiting
a crescent-shaped morphotype is evaluated
using SSU rRNA gene sequence analyses and light
and electron microscopical observations. These
common chlorophytes evolved polyphyletically in 10
different clades of the Chlorophyceae and three
clades of the Trebouxiophyceae. Six clades are
assigned to known genera of Selenastraceae: Kirchneriella,
Nephrochlamys, Raphidocelis, Rhombocystis,
Selenastrum, and Tetranephris. Four other clades,
named following their present genus designation as
Ankistrodesmus-like I and II and Monoraphidium-like I
and II, require further investigation. One crescentshaped
morphotype, which evolved within the Trebouxiophyceae,
is designated as Neocystis mucosa sp.
nov. The other two lineages containing trebouxiophycean
algae with this morphotype are the Elliptochloris
and the Watanabea clades. The taxonomic
placement of the widely used bioassay strain ‘‘Selenastrum
capricornutum’’ NIVA-CHL 1 in the genus
Raphidocelis (species name Raphidocelis subcapitata)
is indicated by molecular data.