<i>Nanobdellota phyl. nov</i> .

<jats:title>Abstract</jats:title> <jats:p> Na.no.bdel.lo'ta. N.L. fem. n. <jats:italic>Nanobdella</jats:italic> , the type genus of the phylum; N.L. suff. ‐ <jats:italic>ota</jats:italic> , ending to denote a phylum; N.L. neut. pl. n. <jats:italic>Nanobdellota</jats:italic> , the phylum <jats:italic>Nanobdella</jats:italic> . </jats:p> <jats:p> The phylum “ <jats:italic>Nanoarchaeota</jats:italic> ” was proposed in 2002 to accommodate the sole species “ <jats:italic>Nanoarchaeum equitans</jats:italic> ,” which is symbiotically associated with a host archaeon <jats:italic>Ignicoccus hospitalis</jats:italic> . Since then, several members of the phylum “ <jats:italic>Nanoarchaeota</jats:italic> ” have been cultivated with their hosts and described. However, until the publication of <jats:italic>Nanobdella aerobiophila</jats:italic> in 2022, no species or genus within the phylum “ <jats:italic>Nanoarchaeota</jats:italic> ” had their names validly published in accordance with the International Code of Nomenclature of Prokaryotes (ICNP). Meanwhile, it was decided recently that the rank of phylum should be included in the current version of ICNP. Therefore, we herein propose the phylum name <jats:italic>Nanobdellota</jats:italic> phyl. nov. with <jats:italic>Nanobdella</jats:italic> as the type genus to enable valid publication of the phylum name. <jats:italic>Nanobdellota</jats:italic> contains the class <jats:italic>Nanobdellia</jats:italic> , whose name is also validly published. Cultivated members of this phylum are obligately symbiotic, only growing in coculture with their specific hosts. Depending on their hosts, they grow under aerobic or anaerobic conditions. Cells are small cocci and occur singly or attached to the cell surface of their hosts. The genome size of the members of this phylum range between 0.49 and 0.67 Mb. </jats:p> <jats:p> <jats:italic>DNA G + C content (mol%)</jats:italic> : 24.2–32.2. </jats:p> <jats:p> <jats:italic>Type genus</jats:italic> : <jats:bold>Nanobdella</jats:bold> Kato et al. 2022 <jats:sup>VP</jats:sup> . </jats:p>