Hypoliths are microbially colonized translucent rocks that represent a key refuge niche in extreme
arid environments such as the Antarctic Dry Valleys. These cryptic microbial assemblages are crucial
as they mediate numerous ecosystem processes. Here, we present the first draft genome of a
hypolith isolate belonging to the α-proteobacterial class and the genus Sphingomonas. The draft
genome of Sphingomonas sp. strain AntH11 shows the capacity of this organism to adapt to the
extreme cold and arid conditions encountered in Antarctic desert soils. Our result also suggests that
its metabolic versatility and multidrug resistance constitutes an opportunistic advantage in
competition with other hypolith-colonizing microorganisms.