The Thermoanaerobacterales is a

polyphyletic A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of conver ...

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

placed within the

class Class or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or objects * Class (philosophy), an analytical concept used differently ...

Clostridia The Clostridia are a highly polyphyletic class of Bacillota, including ''Clostridium'' and other similar genera. They are distinguished from the Bacilli by lacking aerobic respiration. They are obligate anaerobes and oxygen is toxic to them. S ...

, and encompassing four families: the Thermoanaerobacteraceae, the

Thermodesulfobiaceae The family Thermodesulfobiaceae according to the LPSN is located within the order Thermoanaerobacterales and class Clostridia. However, according to the All-Species Living Tree Project it lies outside the clade Bacillota and the genus '' Caldan ...

, the Thermoanaerobacterales Family III. Incertae Sedis, and the Thermoanaerobacterales Family IV. Incertae Sedis, and various unplaced genera. This order is noted for the species' abilities to survive in extreme environments without oxygen and of relatively elevated temperatures for a living being (up to 80-90 °C). An example organism in this order is ''

Thermoanaerobacter ethanolicus ''Thermoanaerobacter ethanolicus'' is a species of thermophilic, anaerobic, non-spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time ...

''.C.Michael Hogan. 2010
''Extremophile''. eds. E.Monosson & C.Cleveland, Encyclopedia of Earth. National Council for Science and the Environment, Washington DC.
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Phylogeny

The Thermoanaerobacterales, as previously mentioned, is

, and consists numerous morphologically similar clades:

Phylogeny

Note:
* polyphyletic Thermoanaerobacterales

References

{{Taxonbar, from=Q871759 Bacteria orders Clostridia Thermophiles Anaerobes Polyphyletic groups