''Ancoracysta'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

eukaryotic The eukaryotes ( ) constitute the Domain (biology), domain of Eukaryota or Eukarya, organisms whose Cell (biology), cells have a membrane-bound cell nucleus, nucleus. All animals, plants, Fungus, fungi, seaweeds, and many unicellular organisms ...

microbes A microorganism, or microbe, is an organism of microscopic size, which may exist in its single-celled form or as a colony of cells. The possible existence of unseen microbial life was suspected from antiquity, with an early attestation in ...

containing the species ''Ancoracysta twista'', a

predatory Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...

protist A protist ( ) or protoctist is any eukaryotic organism that is not an animal, land plant, or fungus. Protists do not form a natural group, or clade, but are a paraphyletic grouping of all descendants of the last eukaryotic common ancest ...

.Janouškovec J, Tikhonenkov DV, Burki F, Howe AT, Rohwer FL, Mylnikov AP, Keeling PJ. "A New Lineage of Eukaryotes Illuminates Early Mitochondrial Genome Reduction", ''Current Biology'' 2017,

Description

''Ancoracysta twista'' was first described in November 2017 in ''

Current Biology ''Current Biology'' is a biweekly peer-reviewed scientific journal that covers all areas of biology, especially molecular biology, cell biology, genetics, neurobiology, ecology, and evolutionary biology. The journal includes research artic ...

''. It was found in a sample collected from the surface of a tropical

aquarium An aquarium (: aquariums or aquaria) is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. fishkeeping, Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aquati ...

brain coral Brain coral is a common name given to various corals in the families Mussidae and Merulinidae, so called due to their generally spheroid shape and grooved surface which resembles a brain. Each head of coral is formed by a colony of geneticall ...

. It actively feeds on '' Procryptobia sorokini'', probably immobilising its prey through discharging a previously unknown type of

extrusome Extrusomes are membrane-bound organelles found in eukaryotic cells that are capable of discharging material contained within to the exterior of the cell. Due to the diversity in structure and function, it is unlikely that different types of extruso ...

named an ancoracyst. Genetic analysis shows that it is not closely related to any known lineage, but it may be most closely related to a grouping of

haptophyte The haptophytes, classified either as the Haptophyta, Haptophytina or Prymnesiophyta (named for '' Prymnesium''), are a clade of algae. The names Haptophyceae or Prymnesiophyceae are sometimes used instead. This ending implies classification at ...

s and

centrohelid The centrohelids or centroheliozoa are a large group of heliozoan protists. They include both mobile and sessile forms, found in freshwater and marine environments, especially at some depth. Characteristics Individuals are unicellular and spher ...

s (

Haptista Haptista is a proposed group of protists made up of centrohelids and haptophytes. Phylogenomic studies indicate that Haptista, together with ''Ancoracysta twista'', forms a sister clade to the SAR supergroup#Internal phylogeny, TSAR Supergroup (b ...

). It is notable for having a gene-rich

mitochondrial genome Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the DNA contained in ...

, the largest known outside the

jakobid Jakobida is an order (sole order in the class Jakobea) of free-living, heterotrophic, flagellar eukaryotes in the clade Discoba. They are small (less than 15 μm), and can be found in aerobic and anaerobic environments. The order Jakobida, b ...

s or ''

Diphylleia rotans ''Diphylleia rotans'' is a eukaryotic microorganism. It is notable for having a gene-rich mitochondrial genome, the largest known outside the jakobid Jakobida is an order (sole order in the class Jakobea) of free-living, heterotrophic, flagellar ...

''. Uniquely, it appears to contain both the nucleus-encoded holocytochrome ''c'' synthase system III ''and'' the mitochondrion-encoded bacterial cytochrome ''c'' maturation system I.

Taxonomy

A 2018 study from

Cavalier-Smith Thomas (Tom) Cavalier-Smith, Royal Society, FRS, Royal Society of Canada, FRSC, Natural Environment Research Council, NERC Professorial Fellow (21 October 1942 – 19 March 2021), was a professor of evolutionary biology in the Departme ...

, Chao & Lewis created a new subphylum and subsequent lower taxonomic ranks for ''Ancoracysta twista''. They also created a new combination for ''Colponema marisrubri'' (Mylnikov & Tikhonenkov, 2009), which was shown to be ultrastructurally similar and phylogenetically close to ''A. twista'', thus renaming it ''A. marisrubri''. This species was later placed into a new genus, '' Nebulomonas'', and is now called '' Nebulomonas marisrubri''. A 2022 study placed ''A. twista'' in a new supergroup

Provora Provora is a supergroup of eukaryotes made up of predatory microbes, whose name implies something such as "protists devouring voraciously". It was reported that ten strains were isolated and cultured in 2022. They are predators of other microor ...

, closely related to other supergroups of

Diaphoretickes Diaphoretickes is a major group of eukaryote, eukaryotic organisms spanning over 400,000 species. The majority of the earth's biomass that carries out photosynthesis belongs to Diaphoretickes. In older classification systems, members of the Diaph ...

such as

, but no longer within Haptista.

References

External links

* * {{Taxonbar, from1=Q54287550, from2=Q47487266 Protists described in 2017 Protist genera Diaphoretickes Monotypic eukaryote genera