Table 1. Classification and general features of M. fervidus V24S^T according to the MIGS recommendations [15].

MIGS ID	Property	Term	Evidence code
	Current classification	Domain Archaea	TAS [16]
		Phylum Euryarchaeota	TAS [17,18]
		Class Methanobacteria	TAS [18,19]
		Order Methanobacteriales	TAS [20-22]
		Family Methanothermaceae	TAS [1,23]
		Genus Methanothermus	TAS [1,23]
		Species Methanothermus fervidus	TAS [1,23]
		Type strain V24S	TAS [1]
	Gram stain	positive	TAS [1]
	Cell shape	straight to curved, single and in pair rods	TAS [1]
	Motility	non-motile	TAS [1]
	Sporulation	not reported	NAS
	Temperature range	61°C–97°C	TAS [1]
	Optimum temperature	83°C	TAS [1]
	Salinity	not reported	NAS
MIGS-22	Oxygen requirement	strict anaerobic	TAS [1]
	Carbon source	CO2	TAS [1]
	Energy source	H2 + CO2	TAS [1]
MIGS-6	Habitat	solfataric fields	TAS [1]
MIGS-15	Biotic relationship	not reported	NAS
MIGS-14	Pathogenicity	no	NAS
	Biosafety level	1	TAS [24]
	Isolation	Icelandic hot spring	TAS [1]
MIGS-4	Geographic location	Kerlingarfjöll mountains, Iceland	TAS [1]
MIGS-5	Sample collection time	1979	NAS
MIGS-4.1 MIGS-4.2	Latitude      Longitude	64.65      19.25	NAS
MIGS-4.3	Depth	surface	TAS [1]
MIGS-4.4	Altitude	1.477 m	NAS

Evidence codes - IDA: Inferred from Direct Assay (first time in publication); TAS: Traceable Author Statement (i.e., a direct report exists in the literature); NAS: Non-traceable Author Statement (i.e., not directly observed for the living, isolated sample, but based on a generally accepted property for the species, or anecdotal evidence). These evidence codes are from of the Gene Ontology project [25]. If the evidence code is IDA, then the property was directly observed by one of the authors or an expert mentioned in the acknowledgements