Ectobacillus
Ectobacillus is a genus of Gram-positive (with the exception of "Ectobacillus funiculus", which is Gram-negative), rod-shaped bacteria in the family "Bacillaceae" within the order "Bacillales". The type species for this genus is "Ectobacillus panaciterrae." "Ectobacillus" is composed of species originally belonging to the genus "Bacillus". The genus "Bacillus" comprises a large number of phylogenetically unrelated bacteria species with a diverse range of biochemical characteristics. The polyphyletic nature of the genus is partly due to the vague criteria used to assign species to this genus (ie. accepting all species that are able to form endospores in aerobic  conditions). Comparative genomic analyses and phylogenetic studies have set out to clarify the complex taxonomic relationship of this genus, resulting in the transfer of many species into novel genera such as "Virgibacillus, Solibacillus, Brevibacillus" and "Alteribacter". In addition, the genus "Bacillus" has been restricted to include only species closely related to "Bacillus subtilis" and "Bacillus cereus". The name "Ectobacillus" is derived from its taxonomic position in relation to "Bacillus". The prefix "ecto-" (which comes from the Greek preposition "ecto", and translates to "outside") and the suffix "-bacillus" (which comes from the Latin noun "Bacillus", referring to a rod or small  staff, as well as "Bacillus", a bacterial genus) come together to form the name "Ectobacillus," meaning "outside of "Bacillus"". Biochemical Characteristics and Molecular Signatures. Members of the genus "Ectobacillus" can be aerobic or facultatively anaerobic. They all are endospore-forming and some members are motile cells. "Ectobacillus" can survive in temperatures ranging from 15°C to 45°C, but optimal growth occurs in the range of 28-35°C. Analyses of genome sequences from "Ectobacillus" have identified five conserved signature indels (CSIs) that are exclusive for "Ectobacillus" species in the proteins 3-isopropylmalate dehydratase small subunit, bacillithiol  biosynthesis deacetylase BshB1, aldo or keto reductase, MBL fold metallo-hydrolase, and CYTH domain-containing protein. These CSIs can be used to demarcate "Ectobacillus" from other "Bacillceae" genera in molecular terms. Taxonomy. As of May 2021, there are a total of 4 species with validly published names in the genus "Ectobacillus". Members of this clade were found to group together in a monophyletic branch in various phylogenetic trees constructed on conserved genome sequences and 16S rRNA sequences. This branching pattern could also be seen in the Genome Taxonomy Database (GTDB), further supporting this classification.