Ancoracysta

Ancoracysta is a genus of eukaryotic microbes containing the species Ancoracysta twista, a predatory protist that appears to be related to Haptista.^[1]

Ancoracysta
Scientific classification
Domain:	Eukaryota
Clade:	Provora
Phylum:	Nebulidia
Class:	Nebulidea
Order:	Nebulidida
Family:	Nebulidae
Genus:	Ancoracysta Janouškovec, Tikhonenkov, Burki, Howe, Rohwer, Mylnikov & Keeling 2017
Species:	A. twista
Binomial name
Ancoracysta twista Janouškovec, Tikhonenkov, Burki, Howe, Rohwer, Mylnikov & Keeling 2017[1]

Description

Ancoracysta twista was first described in November 2017 in Current Biology. It was found in a sample collected from the surface of a tropical aquarium brain coral. It actively feeds on Procryptobia sorokini, probably immobilising its prey through discharging a previously unknown type of extrusome named an ancoracyst.^[1]

Genetic analysis shows that it is not closely related to any known lineage, but it may be most closely related to a grouping of haptophytes and centrohelids (Haptista). It is notable for having a gene-rich mitochondrial genome, the largest known outside the jakobids or Diphylleia rotans. Uniquely, it appears to contain both the nucleus-encoded holocytochrome c synthase system III and the mitochondrion-encoded bacterial cytochrome c maturation system I.^[1]

Taxonomy

A 2018 study from Cavalier-Smith, 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.^[2] This species was later placed into a new genus, Nebulomonas, and is now called Nebulomonas marisrubri.^[3]

A 2022 study placed A. twista in a new supergroup Provora, closely related to other supergroups of Diaphoretickes such as Haptista, but no longer within Haptista.^[3]