GMM 15 [KC255282] Mammoth Cave clone CCU22 [AY221078] Foos7B 111 [EU431749] Ferromanganous microbial [AF292999] Microbial lab scale wastewater treatment clone [DQ988299] Dechlorospirillum sp. str. SN1 [AY171615] Rhodospirillaceae Foos8B 82 [EU431822] Rhodospirillales Azospirillum doebereinerae str. 63 [AJ238567] GMM 99 [KC255375] Alkaline soil, former lake Texcoco clone TX5A_29 [FJ152737] Hyphomonadaceae Rhodobacterales Tallgrass prairie soil clone FFCH13887 [EU133408] Hyphomonas polymorpha str. DSM2665 [AJ227813] Foos8B 92 [EU431831] Foos8B 37 [EU431784] Caulobacteraceae Caulobacterales Brevundimonas sp. Str. V52 [DQ778038] GMM 67 [KC255352] GMM 106 [KC255257] Uranium mill tailings, Bulgaria clone BuhD-104 [FM877535] GMM 53 [KC255341] GMM 130 [KC255270] GMM 110 [KC255258] Soil clone F6-67 [EF688373]

Aspen rhizosphere clone Elev_16S_1231 [EF019869]

GMM 57 [KC255345] Sludge clone S7 [AF234717] Wastewater sludge bioreactor clone AS13 [EU283353] Phyllobacteriaceae & GMM 46 [KC255336] Hyphomicrobiaceae GMM 45p [KC255335]

Uranium mine waste clone JG37-AG-26 [AJ518768] Rhizobiales Aspen rhizosphere clone Amb_16S_981 [EF018690] Rhodopseudomonas cryptolactis str. DSM 9987 [AB087718] GMM 104 [KC255255] Pertechnetate sediment radionuclide clone M14C28 [EU331401] Soil clone X33 [DQ083106] Rock gold mine biofilm clone E09-2 [FM253660] Foos7B 47 [EU431701] Mesorhizobium ciceri str. Rcd301 [AY217118] GMM 121 [KC255264] GMM 143 [KC255278] GMM 141 [KC255277] GMM 25 [KC255319] GMM 184 [KC255307] Alphaproteobacteria GMM 159 [KC255286] GMM 95 [KC255371] GMM 13 [KC255274] GMM 30 [KC255325] Foos8B 86 [EU431826]

Foos8B 96p [EU431758]

Freshwater estuary isolate str. AP-7 [AY145545] Sphingomonas sp. str. B18 [AF410927] Farm soil clone AKYG942 [AY922079] Tallgrass prarie soil clone FFCH3966 [EU133560] Foos8B 69p [EU431810] Foos8B 41 [EU431786] Sphingomonadaceae Foos8B 80 [EU431820] Foos8B 30 [EU431777] Foos8B 63 [EU431806] Foos8B 56 [EU431800] Sphingomonadales >90 GMM 62 [KC255349] <90 and >70 Sphingopyxis alaskensis str. AF01 [AF378796] Foos7B 77 [EU431722] GMM 111 [KC255259] 0.1 Soil clone F6-63 [EF688371] Foos7B 84 [EU431728] Soil clone MeCl 62 [AY439192] To outgroups Poplar tree microcosm clone [AJ863268] GMM 58 [KC255346] GMM 103 [KC255254] GMM 128 [KC255268] GMM 27 [KC255321] PCB contaminated soil clone lhap15 [DQ648974] Deep coal seem groundwater stream clone SWB06 [AB294317] Foos8B 73 [EU431813] Foos8B 33 [EU431780] Foos7B 70 [EU431717] Foos7B 64 [EU431712] Bdellovibrionales Activated sludge clone 1601 [AB286607] Foos7B 52 [EU431706] TCE aerobic groundwater clone Won11(0714) [DQ839503] GMM 18 [KC255302] Electrochemically active oligotrophic artificial wastewater clone oc48 [AY491589] Crude oil contaminated saline soil clone B169 [EU328047] Tallgrass prairie soil clone FFCH2365 [EU134543] Lake Kastoria sediment, Greece clone Kas145B [EF203190] GMM 169 [EU255294] carbinolicus strain DSM 2380 [NR_075013] Foos8B 52p [EU431796] Haliangium ochraceum str. SMP-2 [AB016470]

Foos7B 17 [EU431675] Soil from ginseng field [AB245340] Nannocystineae Myxococcales Grassland soil clone [EF516185] Foos8B 31 [EU431778]

Supplemental Figure 3. Phylogenetic reconstruction among 16S rRNA gene sequence retrieved from moonmilk from Grotta della Foos and Bus della Genziana (labeled in bold) compared to closest relatives affiliated to the Alphaproteobacteria and Deltaproteobacteria. Accession numbers for relatives are included. The scale bar corresponds to distance.