Chloromonas fuhrii sp. nov. (Chlorophyceae), a cosmopolitan alga from colored snow

ABSTRACT

The modern concept of the genus Chloromonas includes a subclade of species found exclusively in snow. We describe Chloromonas (Cr.) fuhrii sp. nov., a new member of this clade, which is closely related to Cr. muramotoi from Japan. The new species is characterised by the absence of a stigma, pyrenoid, and defined papilla, ready loss of flagella in culture, and a single lobed chloroplast. Strains of Cr. fuhrii have been sourced from green, orange, and pink/red snow. The species has been found in Svalbard, Antarctica, and New Zealand, with most genetic variation occurring in Svalbard. The minimal variation present in New Zealand strains suggests a relatively recent arrival. Secondary structure models for ITS2 in the new species demonstrate a separation from Cr. muramotoi due to one CBC. The nine New Zealand strains isolated showed no variation in ITS2 but four variable base positions in ITS1. Inclusion of the single Antarctic and four Svalbard strains resulted in 14 variable positions in ITS2 and 69 in ITS1, with the sequences remaining alignable. The ITS data showed a strong biogeographic signal, both in total in an unrooted tree, and using ITS2 alone with Cr. muramotoi as an outgroup. The absence of a stigma in this species prompted a survey of the literature, showing that stigma absence in Chloromonas is strongly associated with the snow habitat, occurring at about 10 times the rate observed in other habitats, perhaps owing to the difficulty of phototaxis in snow with abundant reflected light.

KEYWORDS:

• Biogeography
• Chloromonas
• Phylogenetic analysis
• Snow algae
• Stigma

ACKNOWLEDGEMENTS

We thank A. Monks (Manaaki Whenua – Landcare Research, Dunedin), J. Robinson (Uenuku Tribal Authority), and N. Sloan for assistance in the field; Kāti Huirapa Rūnaka ki Puketeraki, Ngāti Rangi, Uenuku Tribal Authority, and Te Rūnanganui o Ngāti Hikairo for engaging with us regarding collecting and DNA sequencing requirements for collections in Otago and the central North Island of New Zealand; and the New Zealand Department of Conservation for assistance with this engagement. T. Beer kindly resequenced the 18S gene of strain CCCryo 032-99. Collecting from the New Zealand conservation estate was granted under concession CA31615-OTH. We thank R. Hoham and an anonymous reviewer for many helpful comments that improved the original manuscript.

DISCLOSURE STATEMENT

No potential conflicts of interest are reported by the authors(s).

Supplementary Information

Supplemental data for this article can be accessed online at https://doi.org/10.1080/00318884.2024.2313780

Additional information

Funding

PMN was supported by Strategic Science Investment Fund Core funding for Crown Research Institutes from the Ministry of Business, Innovation and Employment’s Science and Innovation Group, New Zealand. RBK was supported by Western Washington University for field work in New Zealand. TL was supported by the DFG - Deutsche Forschungsgemeinschaft grants Fu 345/6-2, Fu 345/6-3 and Le 1275/2-2.