Reclassification of the genus : proposal of two new genera, gen. nov. to accommodate and gen. nov. to accommodate and .

The genus , currently including four species, is a member of the order , class and consists of obligately alkaliphilic and extremely halophilic members found exclusively in highly alkaline hypersaline soda lakes. The species were classified into this genus mostly based on phylogenetic analysis of the 16S rRNA gene. However, a more advanced phylogenomic reconstruction based on 122 conserved single-copy archaeal protein markers clearly indicates a polyphyletic origin of the species included into this genus, thus warranting its reclassification into three separate genera. We therefore propose to transfer (type strain N-1311) to a new genus as comb. nov. and to transfer (type strain JW/NM-HA 15) and (type strain AArc1) to a new genus as comb. nov. and comb. nov. The phylogenomic differentiation of these four species is also supported by the ANI/AAI distances and unique phenotypes. The most important physiological differences includes a previously unreported ability for cellulose and xylan utilization in , thermophily in and anaerobic sulfur respiration in . We further present an emended description of .