Fig. 1

The evolutionary history was inferred using the Neighbor-Joining method. The optimal tree with the sum of branch length = 43.50359217 is shown. The percentage of replicate trees in which the associated taxa clustered together in the bootstrap test (500 replicates) is shown next to the branches. The tree is drawn to scale, with branch lengths in the same units as those of the evolutionary distances used to infer the phylogenetic tree. The evolutionary distances were computed using the Maximum Composite Likelihood method and are in the units of the number of base substitutions per site. The analysis involved 21 nucleotide sequences. Codon positions included were 1st + 2nd + 3rd + Noncoding. All positions with less than 95 % site coverage were eliminated. That is, fewer than 5 % alignment gaps, missing data, and ambiguous bases were allowed at any position. There were a total of 1,157 positions in the final dataset. Methanocaldococcus jannaschii strain JCM 10045 16S rDNA sequence was used as an outgroup. Evolutionary analyses were conducted in MEGA5