Supergroup (biology)

A supergroup or super-group, in systematics, is a large group of organisms that share one common ancestor and have important defining characteristics. It is an informal, mostly arbitrary rank in biological taxonomy that is often greater than phylum or kingdom, although some supergroups are also treated as phyla.

Eukaryotic supergroups

Since the decade of the 2000s, the eukaryotic tree of life has been divided into 5–8 major groupings called 'supergroups'. These groupings were established after the idea that only monophyletic groups should be accepted as ranks, as an alternative to the use of paraphyletic kingdom Protista. In the early days of the eToL six traditional supergroups were considered: Amoebozoa, Opisthokonta, "Excavata", Archaeplastida, "Chromalveolata" and Rhizaria. Since then, the eToL has been rearranged profoundly, and most of these groups were found as paraphyletic or lacked defining morphological characteristics that unite their members, which makes the 'supergroup' label more arbitrary.
Currently, the addition of many lineages of newly discovered protists and the use of phylogenomic analyses have brought a new, more accurate supergroup model. These are the current supergroups of eukaryotes:

TSAR, constituted by Telonemia and the SAR clade. It is estimated to occupy up to half of all eukaryotic diversity, since it includes multiple major groups such as diatoms, dinoflagellates, seaweeds, ciliates, foraminiferans, radiolarians, and the apicomplexan and oomycete parasites. It essentially contains the majority of "Chromalveolata".
Haptista, previously in "Chromalveolata", comprising the haptophyte algae and centrohelids.
Cryptista, previously in "Chromalveolata", comprising the cryptomonads, katablepharids and the enigmatic Palpitomonas.
Archaeplastida, constituted by the lineages that acquired chloroplasts through primary endosymbiosis: Chloroplastida, Rhodophyta, Glaucophyta and Rhodelphis.
Amorphea, composed by the Amoebozoa and the Opisthokonta. They're related to the breviates and the apusomonads, and together form the clade Obazoa.
CRuMs, composed by the free-living protozoan groups Collodictyonidae, Rigifilida and Mantamonas.
Discoba, constituted by Discicristata, Jakobida and Tsukubamonas. It is the biggest remaining clade of the "Excavata".
Metamonada, previously part of the "Excavates", entirely containing anaerobic protists.
Disparia, the most recently described supergroup, containing the clades Provora, Hemimastigophora, and Caelestes.

Many orphan groups of free-living protozoa remain left behind, unable to be added to a supergroup, such as: Picozoa, Malawimonadida, Ancyromonadida, Breviatea, Apusomonadida, etc.
A possible modern topology of the eToL would be the following :

Prokaryotic supergroups

The term 'supergroup' is used in phylogenetic studies of bacteria, in a smaller sense than within eukaryotes. As of 2021, it is very commonly used for naming clades within the genus Wolbachia.