Previously, methanogenic organisms had only been described in the Euryarchaeota. Now, Evans et al. report two near-complete genomes that provide strong evidence for methanogenesis in a second archaeal phylum, the Bathyarchaeota. The genomes — obtained from an Australian methane well — contain genes indicative of methylotrophic methanogenesis using a diverse set of methylated compounds. Interestingly, one of the genomes also contains genes for complex fermentation and the other also contains genes for β-oxidation; neither of these processes have previously been seen in methanogens. By contrast, structural prediction suggested that both genomes encode a functional methyl-coenzyme M reductase complex (MCR), a universal feature of methanogens. A survey of metagenomes from geographically disparate high-methane- flux environments identified additional non-euryarchaeotal examples of genes encoding MCR components. The authors propose that methanogenesis arose in a common ancestor of the two phyla, rather than in the Euryarchaeota, and thus has a more ancient origin than has sometimes been suggested.