*3.1.1. Different species merged into a single clade*

*Escherichia coli* and some *Shigella* species are combined in a single clade by ribosomal marker distance. *Shigella*, which is recognized as a genus with four species in most situations, taxo‐ nomically belongs to the diverse *E. coli* group, but the genus-level distinction has been retained due to historical recognition of its medical significance*. Shigella* has adapted to higher primates as the only natural hosts.

The genus *Brucella* consists of 10 classically recognized species [http://icsp.org/subcommittee/ brucella/] based on antigenic/biochemical characteristics and primary host species*: Brucella abortus*(cattle); *Brucella canis* (dogs); *Brucella ceti* (marine mammals); *Brucella inopinata*; *Brucella melitensis* (sheep and goats); *Brucella microti*; *Brucella neotomae* (rodents); *Brucella ovis* (sheep); *Brucella pinnipedialis* (marine mammals); *Brucella suis* (swine, cattle, rodents, wild ungulates), and recently described in [24] *Brucella papionis* isolated from baboons (*Pappio* spp.). The wave of Next-Generation Sequencing brought in almost a hundred new isolates from a population of *Brucella*, which are clearly distinct from currently recognized species that are tentatively designated at the species level. These unnamed isolates have not yet been characterized using traditional methods, or the species name has not yet been validly published. *Brucella* genus– level clade is shown in Figure 6.
