(Prasiolales, Trebouxiophyceae), a New Species Occurring in Hairs of the Sloth .

The monotypic genus has been known for a long time, but is often overlooked because of difficulties in identification and the morphological variability between uniseriate filaments and cell packages forming pseudoparenchymatic thalli depending on age. We investigated a strain (SAG 84.81) originally denoted as , which was isolated from the hairs of the sloth and compared it with other available strains of and of the sister genus . Our investigations clearly showed that this strain differed in morphology, especially of the chloroplast, from those originally described for . Phylogenetic analyses of the SSU and ITS rDNA sequences revealed that the strain SAG 84.81 is sister to several strains of within the clade (Trebouxiophyceae). Using the ITS-2/CBC approach, we clearly demonstrated that this strain represented a new species of , which we proposed here as . In addition, we evaluated the ITS-2/CBC approach by comparing it with the two species of . All investigated strains showed CBCs and HCBCs, which support their species delimitation. The sequencing data of available in GenBank were phylogenetically re-evaluated by including all representatives of the Ulotrichales (Ulvophyceae). Our analyses showed that these sequences formed their own lineage within this order.