The genus Halomonas, a member of the family Halomonadaceae (Franzmann et al., 1988) of the order Oceanospirillales within the class Gammaproteobacteria, was first proposed by Vreeland et al. (1980). Currently, approximately 69 species of the genus Halomonas with validly published name are listed in the List of Prokaryotic Names with Standing in Nomenclature (LPSN; https://lpsn.dsmz.de/genus/halomonas). Members of the genus Halomonas are predominantly halophilic and widely distributed in diverse saline environments, including saline soils (Dou et al., 2015; Li et al., 2022; Xu et al., 2024), seawater (Kim et al., 2007; Diéguez et al., 2020; Lin et al., 2023), salt lakes (Mormile et al., 1999; Quillaguamán et al., 2004; Wu et al., 2008; Chen et al., 2011), wet-salted hides (Li et al., 2020), tidal flats (Koh et al., 2017), saline wells (Xu et al., 2007), littoral salterns (Qu et al., 2011), salt flats (Yoo et al., 2022), deep-sea sediments (Wang et al., 2021), and marine ascidians (Romanenko et al., 2002). Species of the genus Halomonas are Gram-stain-negative, halophilic or halotolerant, and either aerobic or facultatively anaerobic (Ventosa et al., 2021). Their major polar lipids consist of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, with Q-9 serving as the predominant respiratory quinone. The genomic DNA G + C content ranges from 51.4 to 74.3 mol% (de la Haba et al., 2023). Species of the genus Halomonas can readily adapt to various environmental conditions, due to its metabolic and physiological versatility. Some Halomonas species exhibited the capacity to produce exopolysaccharides, polyhydroxyalkanoate and compatible solutes (Amjres et al., 2011; Cánovas et al., 2000; Schwibbert et al., 2011; Kawata, 2014), degrade aromatic compounds (García et al., 2004; Hajizadeh et al., 2015), tolerate heavy metals (Xu et al., 2013), perform denitrification (González-Domenech et al., 2010; Guo et al., 2013), etc., which make Halomonas species have promising applications in the biotechnology industry (Xiao-Ran et al., 2018).

During the investigation of the bacterial diversity and novelty in salt lakes of the Ngari Prefecture, Xizang Autonomous Region, China. Two moderately halophilic bacterial strains, designated as MA07–2T and RA08–2, were isolated from sediment samples of saline lakes. In this study, a polyphasic taxonomic investigation, combining genomic, phenotypic, and chemotaxonomic analyses, was employed to determine their precise taxonomic positions.