A novel centrohelid protist from Siberian permafrost

Area of Science:

• Microbiology
• Protistology
• Paleontology

Background:

• Permafrost ecosystems harbor ancient microbial life, but protist diversity and viability, especially centrohelid heliozoans, are poorly understood.
• Centrohelid heliozoans are ecologically significant protists found in various environments.

Purpose of the Study:

• To investigate the diversity and long-term viability of protists in permafrost.
• To describe a new species of centrohelid heliozoan from Siberian permafrost.

Main Methods:

• Isolation and enrichment culture of a centrohelid heliozoan from a Late Pleistocene Siberian permafrost core (9 m depth, ~39,000 years BP).
• Integrative taxonomic approach using light microscopy, scanning electron microscopy, and 18S rRNA gene sequencing.
• Phylogenetic analysis to determine evolutionary relationships.

Main Results:

• Description of a new species, Acanthocystis yamallongha sp. nov., characterized by unique spiral-like ridge ornamentation on plate-scales and bifurcated spine-scales.
• A. yamallongha exhibits significant genetic divergence, suggesting an independent evolutionary lineage.
• Evidence for the long-term viability of Acanthocystidae cysts over geological timescales.

Conclusions:

• Permafrost is a crucial reservoir for uncovering hidden protist diversity and understanding their evolutionary history.
• The discovery of A. yamallongha underscores the importance of exploring permafrost for novel microbial life.
• Ancient protist cysts can maintain viability over tens of thousands of years.