The Family Halomonadaceae

Abstract

The Halomonadaceae (Franzmann et al., 1988) presently contains representatives of two genera, the type genus Halomonas and at least one species of the genus Deleya (D. aesta) (see Chapter 168). The establishment of the family was suggested because Sab values obtained from 16S rRNA catalogs show that Halomonas and Deleya are phylogenetically isolated from all other major groups of the gamma subdivision of the Proteobacteria (Stackebrandt et al., 1988 Woese et al., 1985), forming an internally coherent cluster at an Sab of 0.60. Internally, the family contains two subgroups composed of the type species of Halomonas, H. elongata and Halomonas halmophilum (formerly Flavobacterium halmophilum). This cluster forms at an Sab of 0.66. The companion cluster contains H. subglaciescola and D. aesta and forms at an Sab of 0.67. The position of the other halomonads (Table 1) within the phylogeny is not presently known.