The curious structure and resilience of the newfound species was remarkable, but a genetic analysis revealed S. arienae was hiding even more stunning surprises. After sequencing the genome and cross-referencing it with existing databases, the researchers determined this organism didn\u2019t belong to any previously recognized lineages of eukaryotes. Instead, S. arienae, along with a handful of other mysterious protist relatives, constituted a new supergroup, called Disparia. A search of environmental DNA databases indicated S. arienae is (somewhat paradoxically) both rare and widespread, living a quiet life in marine sediments.<\/p>\n
![\"<strong>TINY](\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/11\/6092b43f49d53122531dccbbd7e2e4f6.jpeg\"\/)
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TINY HUNTER:<\/strong> Microscopic view of S. arienae displaying celestiosome protusions used to capture bacterial prey. Image from Valt, M., et al. Nature (2025).<\/p>\n Even more surprising was the DNA inside S. arienae\u2019s mitochondria. Tucked in those organelles was the gene secA, a fragment of a protein translocation system inherited from the bacterial ancestor that gave rise to mitochondria, and a sequence that\u2019s been lost in almost all other eukaryotic species. According to the endosymbiotic theory, mitochondria were once free-living prokaryotic cells that were engulfed by precursors to eukaryotic cells. After this intimate interaction, eukaryotic cells housed mitochondria, which provided energy to the partnership and resulted in the profusion of eukaryotes we see today.<\/p>\n Read more: \u201c<\/strong>The Unique Merger That Made You (and Ewe, and Yew)<\/strong><\/a>\u201d<\/strong><\/p>\n In other words, S. arienae is essentially a living fossil, allowing researchers an unprecedented glimpse into the evolution of eukaryotic life.<\/p>\n \u201cSolarion is a remarkable reminder of how little we still know about the diversity of microbial life,\u201d study authors Ivan \u010cepi\u010dka and Marek Valt said in a statement<\/a>. \u201cThe discovery of such an evolutionarily deep lineage\u2014essentially a living fossil\u2014shows that key parts of the eukaryotic story remain hidden in places we rarely explore.\u201d<\/p>\n Tree-of-life-changing scientific breakthroughs: Always in the last place you look.<\/p>\n Enjoying\u00a0 Nautilus<\/a>? Subscribe to our free newsletter<\/a>.<\/p>\n Lead image: Charles University<\/p>\n