Verrucomicrobia is a recently described phylum of bacteria. This phylum contains only a few described species (Verrucomicrobium spinosum, is an example, the phylum is named after this). The species identified have been isolated from fresh water

Fresh Water

Fresh Water is the debut album by Australian rock and blues singer Alison McCallum, released in 1972. Rare for an Australian artist at the time, it came in a gatefold sleeve...

 and soil

Soil

Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...

 environments and human feces. A number of as-yet uncultivated species have been identified in association with eukaryotic hosts including extrusive explosive ectosymbionts of protists and endosymbionts of nematodes residing in their gametes. While verrucae is another name for the warts often found on hands and feet, this phylum is so called not because it is a causative agent thereof, but because of its wart-like morphology.

Evidence suggests that verrucomicrobia are abundant within the environment, and important (especially to soil cultures). This phylum is considered to have two sister phyla: Chlamydiae

Chlamydiae

Chlamydiae is a bacterial phylum and class whose members are obligate intracellular pathogens. Many Chlamydiae coexist in an asymptomatic state within specific hosts, and it is widely believed that these hosts provide a natural reservoir for these species....

 and Lentisphaerae

Lentisphaerae

Lentisphaerae is a phylum of bacteria closely related to Chlamydiae and Verrucomicrobia.It includes two monotypic orders Lentisphaerales and Victivallales. Phylum members can be aerobic or anaerobic and fall under two distinct phenotypes. One consists of terrestrial gut microbiota from mammals...

.

Cavalier-Smith has postulated that the Verrucomicrobia belong in the clade Planctobacteria

Planctobacteria

Planctobacteria is a taxon created by Cavalier-Smith, specifically a division Historically bacteria were considered plants consequently the usage of "division" over "phylum" was brought over when the kindgom Monera was established. The bacteriological code has since imposed that the rank should be...

 in the larger clade Gracilicutes

Gracilicutes

Gracilicutes is a controversial taxon in Bacterial taxonomy.Traditionally Gram staining results were most commonly used as a classification tool, consequently until the advent of molecular phylogeny, the Kingdom Prokaryotae was divided into four divisions,*...

. 16S

16S ribosomal RNA

16S ribosomal RNA is a component of the 30S subunit of prokaryotic ribosomes. It is approximately 1.5kb in length...

 rRNA data corroborate that view.
Recently the whole genome

Genome

In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....

 of Methylacidiphilum infernorum was sequenced

DNA sequencing

DNA sequencing includes several methods and technologies that are used for determining the order of the nucleotide bases—adenine, guanine, cytosine, and thymine—in a molecule of DNA....

 (2.3 Mbp

Base pair

In molecular biology and genetics, the linking between two nitrogenous bases on opposite complementary DNA or certain types of RNA strands that are connected via hydrogen bonds is called a base pair...

). On the single circular chromosome

Chromosome

A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...

, 2473 predicted proteins were found, 731 of which had no detectable homologs. These analyses also revealed many possible homologies

Homology (biology)

Homology forms the basis of organization for comparative biology. In 1843, Richard Owen defined homology as "the same organ in different animals under every variety of form and function". Organs as different as a bat's wing, a seal's flipper, a cat's paw and a human hand have a common underlying...

 with Proteobacteria

Proteobacteria

The Proteobacteria are a major group of bacteria. They include a wide variety of pathogens, such as Escherichia, Salmonella, Vibrio, Helicobacter, and many other notable genera....

.

Phylogeny

The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LSPN) and the phylogeny is based on 16S rRNA-based LTP release 106 by The All-Species Living Tree Project 
Notes:

♠ Strain found at the National Center for Biotechnology Information

National Center for Biotechnology Information

The National Center for Biotechnology Information is part of the United States National Library of Medicine , a branch of the National Institutes of Health. The NCBI is located in Bethesda, Maryland and was founded in 1988 through legislation sponsored by Senator Claude Pepper...

 (NCBI) but has no standing with the Bacteriological Code (1990 and subsequent Revision) as detailed by List of Prokaryotic names with Standing in Nomenclature (LPSN) as a result of the following reasons:

• No pure culture isolated or available for Prokayotes.

• Not validly published because the effective publication only documents deposit of the type strain in a single recognized culture collection.

• Not approved and published by the International Journal of Systematic Bacteriology  or the International Journal of Systematic and Evolutionary Microbiology

International Journal of Systematic and Evolutionary Microbiology

The International Journal of Systematic and Evolutionary Microbiology is a peer-reviewed scientific journal in the field of microbial systematics, first published in 1951...

(IJSB/IJSEM).