Abstract
To separate and redefine the ambiguous
Holosticha
-complex, a confusing group of hypotrichous ciliates, six strains belonging to five morphospecies of three genera,
Holosticha heterofoissneri, Anteholosticha
sp. pop1,
Anteholosticha
sp. pop2,
A. manca, A. gracilis
and
Nothoholosticha fasciola
, were analyzed using 12 restriction enzymes on the basis of amplified ribosomal DNA restriction analysis. Nine of the 12 enzymes could digest the DNA products, four (
Hinf
I,
Hind
III,
Msp
I,
Taq
I) yielded species-specific restriction patterns, and
Hind
III and
Taq
I produced different patterns for two
Anteholosticha
sp. populations. Distinctly different restriction digestion haplotypes and similarity indices can be used to separate the species. The secondary structures of the five species were predicted based on the ITS2 transcripts and there were several minor differences among species, while two
Anteholosticha
sp. populations were identical. In addition, phylogenies based on the SSrRNA gene sequences were reconstructed using multiple algorithms, which grouped them generally into four clades, and exhibited that the genus
Anteholosticha
should be a convergent assemblage. The fact that
Holosticha
species clustered with the oligotrichs and choreotrichs, though with very low support values, indicated that the topology may be very divergent and unreliable when the number of sequence data used in the analyses is too low.