Supplementary file 3_Taxonomy of Arctic sea ice-associated rotifers of the genus Synchaeta based on novel 18S and COI sequences and morphological observations.pdf

Despite their role in the sea ice food web as grazers, aspects related to their function and biodiversity remain poorly studied at the species level. Arctic sea ice rotifers, though commonly occurring across the Arctic seas, have mostly been examined microscopically, with few studies identifying them beyond the phylum level.</p>Methods<p>To address this taxonomic knowledge gap, we investigated the genetic diversity of 41 sympagic rotifer individuals collected in the Barents Sea and Central Arctic Ocean basins between 2019 and 2025.

Using general invertebrate/eukaryotic primers targeting the COI and 18S rRNA genes, we performed PCRs and Sanger sequencing on Chelex-extracted DNA of these specimens.</p>Results<p>We found four previously unknown COI lineages of the genus Synchaeta. Morphological observations tentatively associate these four novel lineages with the known ice-associated taxa S. hyperborea, S. tamara, Synchaeta sp. and S. glacialis or S. cecilia.