Unearthed from old soils: New records of Antarctic tardigrades, nematodes, and rotifers in the Prince Charles Mountains based on partial sequences of Cytochrome c oxidase subunit I

Despite only 0.3% of Antarctica being ice-free, those areas harbor diverse small organisms such as tardigrades, nematodes, and rotifers. The habitats of these cryptic organisms face threats from human activity, climate change, and pollution. Biodiversity surveys are essential for managing their protection and such surveys have been proven well possible in Antarctica using environmental DNA (eDNA) analysis. Early eDNA research had greatly benefited from high-throughput sequencing using the now obsolete 454 pyrosequencing technique, which at the time offered superior read length to the Illumina platform. In a 2011-12 expedition to the remote Prince Charles Mountains we had collected soil samples, from which we amplified and described 18S Ribosomal 1 RNA gene sequences. Recently we reanalysed concomitantly generated 454-derived Cytochrome Oxidase Subunit 1 (“COI”) amplicons from those soils, making use of now updated reference data. From our “historic” 454 data we now can provide additional records for some Antarctic taxa, including tardigrades Acutuncus antarcticus and Macrobiotus hufelandi, the nematodes Plectus frigophilus and Plectus murrayi, and rotifers such as Habrotrocha angularis. We show that reanalysing past eDNA projects can yield novel information as reference data collections grows, at the same highlighting the need to curate and further expand those data collections using voucher specimen.