Anaerobic sulfate-reducing enrichment cultures consuming mid-chain alkanes from pentane to tetradecane growing at 70C were established from Guaymas Basin (Gulf of California, Mexico) sediment. The cultures were sequenced on the Illumina HiSeq2500 sequencing platform. Two novel archaea belonging to the genus Candidatus Alkanophaga oxidize the alkanes, whereas a novel Thermodesulfobacterium species reduces sulfate.