Fig 1.
The morphology of Chionaster nivalis.
A. An example of a red snow community with an above-average abundance of C. nivalis. Red algal cells likely represent Chlamydomonas nivalis. B. A light micrograph depicting the typical morphology of C. nivalis. Note the three radiating arms and globular cytoplasm. C-D. Fluorescent (C) and light (D) micrographs of a DAPI-stained individual. E-G. Light micrographs of C. nivalis demonstrating morphological variations such as bent extensions (E), a non-central cytoplasm (F), and a smaller four-armed individual (G). Scale bars: 150 μm (A), 30 μm (B-G).
Fig 2.
Phylogenetic placement of Chionaster nivalis.
A maximum-likelihood phylogeny was generated based on a concatenation of the internal transcribed spacer (ITS) and D1-D2 region of the LSU rRNA gene from C. nivalis, related Tremellomycetes, environmental sequences, and an Agaricomycete outgroup, using the SYM+R6 nucleotide substitution model [43]. All species are represented by both the ITS and the D1-D2 with the exception of certain uncultured environmental fungi and C. nivalis 97C (see S1 Table). Statistical support is shown at each node and was generated from 1000 ultrafast bootstraps (UFB), 1000 non-parametric bootstraps (NPB), and Bayesian posterior probabilities (PP). Values above 95 UFB, 95 NPB, and 0.99 PP are indicated with black circles whereas values below 75 UFB, 75 NPB, and 0.95 PP are not shown. Chionaster nivalis is highlighted in black and the five recognized Tremellomycete orders have been outlined in grey. Sample localities for each sequence branching within the Chionasterales have been denoted with coloured circles. For clarity certain branch lengths have been reduced by 50% as denoted by the hashed lines and clades comprising over three representatives of exclusively the same genera were collapsed and shown as wedges. See S1 Table for a list of taxa and their respective accession numbers. B. A map illustrating the locations in which members of the Chionasterales were identified. Sample types and altitudes are denoted. Altitudes were estimated using FreeMapTools.com.