Imasa | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Malawimonada |
Phylum: | Malawimonada |
Class: | Malawimonadea |
Order: | Malawimonadida |
Family: | Imasidae Heiss, Simpson & Kim 2020 |
Genus: | Imasa Heiss, Simpson & Kim 2020 |
Species: | I. heleensis |
Binomial name | |
Imasa heleensis Heiss, Simpson & Kim 2020 | |
Type strain | |
AMNH_IZC 00343331 |
Imasa is a genus of marine flagellates containing the single species Imasa heleensis, discovered in 2020 in the Solomon Islands. [1] It is the first marine member of a basal group of eukaryotes known as Malawimonadida. [2] It is the only member of the family Imasidae. [1]
The genus name Imasa is the name of the research vessel used to obtain the cells of Imasa heleensis that were isolated. It refers to the pause taken by a crocodile between its emergence from the water and its attack. This pause between actions is resembled by the movement of the anterior flagellum of Imasa, which often appears to pause near the point between the extension and recovery strokes. The species epithet heleensis refers to ‘Hele’, which is the name of the isles containing the collection site of Imasa heleensis at Solomon Islands. As with the genus name, it is common among the indigenous languages of the region. [1]
Imasa heleensis was isolated from a marine shallow lagoon. Like the other two accepted species of malawimonads Gefionella okellyi and Malawimonas jakobiformis , which were isolated from soil and freshwater respectively, Imasa is ecologically associated with a particulate substrate. However, its ability to generate a protrusion from the posterior end of the cell is unusually long (~3 μm when suspended, ~15-20 μm when adhered to the substrate) compared to its terrestrial counterparts (~1 μm in G. okellyi). As for the ventral groove, it only runs the anterior half of the cell in Imasa heleensis, while in the rest of malawimonads it runs the whole length of the cell. [1]
An additional characteristic of Imasa is its shorter flagellar vane compared to other malawimonads. The vanes end abruptly in a steeper angle with the axoneme, which may result in the generation of fluid movement from a shorter length of the posterior flagellum. [1]
The mitochondrial genome of Imasa heleensis is similar to other malawimonads, except for the presence of the sdh3 gene, which is absent in any other known malawimonad. [1]
Imasa is the first marine malawimonad taxon to be described. According to phylogenetic analyses based on SSU rRNA genes, it is the sister taxon to the rest of malawimonads, the Gefionella + Malawimonas clade. Because of this, Imasa was placed in a separate family, Imasidae, while the family Malawimonadidae was reserved for the other two genera. [1]
Malawimonadida |
| ||||||
Malawimonadidae is a family of unicellular eukaryotes of outsize importance in understanding eukaryote phylogeny.
Carpediemonas is genus of Metamonada, and belongs to the group Excavata. This organism is a unicellular flagellated eukaryote that was first discovered in substrate samples from the Great Barrier Reef. Carpediemonas can be found in anaerobic intertidal sediment, where it feeds on bacteria. A feature of this species is the presence of a feeding groove, a characteristic of the excavates. Like most other metamonads, Carpediemonas does not rely on an aerobic mitochondrion to produce energy. Instead, it contains hydrogenosomes that are used to produce ATP. This organism has two flagella: a posterior one used for feeding on the substrate, and an anterior one that moves in a slower sweeping motion. Carpediemonas is assigned to the fornicates, where similar Carpediemonas-like organisms are used in researching the evolution within excavates. Although Carpediemonas is a member of the metamonads, it is unusual in the sense that it is free-living and has three basal bodies.
Malawimonas is genus of unicellular, heterotrophic flagellates with uncertain phylogenetic affinities. They have variably being assigned to Excavata and Loukozoa. Recent studies suggest they may be closely related to the Podiata.
Jakobids are an order of free-living, heterotrophic, flagellar eukaryotes in the supergroup Excavata. They are small, and can be found in aerobic and anaerobic environments. The order Jakobida, believed to be monophyletic, consists of only twenty species at present, and was classified as a group in 1993. There is ongoing research into the mitochondrial genomes of jakobids, which are unusually large and bacteria-like, evidence that jakobids may be important to the evolutionary history of eukaryotes.
Monocercomonoides is a genus of flagellate Excavata belonging to the order Oxymonadida. It was established by Bernard V. Travis and was first described as those with "polymastiginid flagellates having three anterior flagella and a trailing one originating at a single basal granule located in front of the anteriorly positioned nucleus, and a more or less well-defined axostyle". It is the first eukaryotic genus to be found to completely lack mitochondria, and all hallmark proteins responsible for mitochondrial function. The genus also lacks any other mitochondria related organelles (MROs) such as hydrogenosomes or mitosomes. Data suggests that the absence of mitochondria is not an ancestral feature, but rather due to secondary loss. Monocercomonoides sp. was found to obtain energy through an enzymatic action of nutrients absorbed from the environment. The genus has replaced the iron-sulfur cluster assembly pathway with a cytosolic sulfur mobilization system, likely acquired by horizontal gene transfer from a eubacterium of a common ancestor of oxymonads. These organisms are significant because they undermine assumptions that eukaryotes must have mitochondria to properly function. The genome of Monocercomonoides exilis has approximately 82 million base pairs, with 18 152 predicted protein-coding genes.
Platysulcus tardus is an eukaryotic microorganism that was recently discovered to be the earliest diverging lineage of the Heterokont phylogenetic tree. It is the only member of the family Platysulcidae, order Platysulcida and class Platysulcea.
Mantamonads are a group of free-living heterotrophic flagellates that move primarily by gliding on surfaces. They are classified as one genus Mantamonas in the monotypic family Mantamonadidae, order Mantamonadida and class Glissodiscea. Previously, they were classified in Apusozoa as sister of the Apusomonadida on the basis of rRNA analyses. However, mantamonads are currently placed in CRuMs on the basis of phylogenomic analyses that identify their closest relatives as the Diphylleida and Rigifilida.
Rhodelphis is a single-celled archaeplastid that lives in aquatic environments and is the sister group to red algae and possibly Picozoa. While red algae have no flagellated stages and are generally photoautotrophic, Rhodelphis is a flagellated predator containing a non-photosynthetic plastid. This group is important to the understanding of plastid evolution because they provide insight into the morphology and biochemistry of early archaeplastids. Rhodelphis contains a remnant plastid that is not capable of photosynthesis, but may play a role in biochemical pathways in the cell like heme synthesis and iron-sulfur clustering. The plastid does not have a genome, but genes are targeted to it from the nucleus. Rhodelphis is ovoid with a tapered anterior end bearing two perpendicularly-oriented flagella.
Stygiella /ˌstɪ.d͡ʒiˈɛ.lə/ is a genus of free-living marine flagellates belonging to the family Stygiellidae in the jakobids (excavata).
Minimassisteria is a marine bacterivorous genus of protists with only one species, M. diva, that presents three different lifestyle forms. It has a widespread geographic distribution. It is an amoeboflagellate most closely related to Massisteria, and together comprise the family Massisteriidae.
Malawimonads are a small group of microorganisms with a basal position in the evolutionary tree of eukaryotes, containing only three recognized species. They're considered part of a paraphyletic group known as "Excavata".
Tunicaraptor is a genus of marine microbial protists containing the single species Tunicaraptor unikontum, discovered in 2020 from marine waters of Chile. It is a lineage of predatorial flagellates closely related to animals. It has a rare feeding structure not seen in other opisthokonts.
Syssomonas is a monotypic genus of unicellular flagellated protists containing the species Syssomonas multiformis. It is a member of Pluriformea inside the lineage of Holozoa, a clade containing animals and their closest protistan relatives. It lives in freshwater habitats. It has a complex life cycle that includes unicellular amoeboid and flagellated phases, as well as multicellular aggregates, depending on the growth medium and nutritional state.
Mantamonas plastica is a species of marine heterotrophic biflagellates described in 2011. It is the type species of the Mantamonadida, a basal eukaryotic lineage within a clade known as CRuMs.
Phycophthorum is a monotypic genus of protists that parasitize diatoms, containing the sole species Phycophthorum isakeiti. It was discovered in 2020 in the coastal waters of Norway, as parasites of diatoms belonging to the genus Pleurosigma.
Thecamonadinae is a subfamily of heterotrophic protists. It is a monophyletic group, or clade, of apusomonads, a group of protozoa with two flagella closely related to the eukaryotic supergroup Opisthokonta. The subfamily contains two genera Chelonemonas and Thecamonas, which are found in marine habitats.
Colponemids are free-living alveolates, unicellular flagellates related to dinoflagellates, apicomplexans and ciliates. They are predators of other small eukaryotes, found in freshwater, marine and soil environments. They do not form a solid clade, but a sparse group of deep-branching alveolate lineages.
Paratrimastix pyriformis is a species of free-living (non-parasitic) anaerobic freshwater bacteriovorous flagellated protists formerly known as Trimastix pyriformis and Tetramitus pyriformis.
Skoliomonas is a genus of anaerobic protists closely related to barthelonids, a small group of basal eukaryotes within the phylum Metamonada. It is a monotypic genus containing the sole species Skoliomonas litria. Members of this genus are informally named skoliomonads. They are found inhabiting hypersaline alkaline lakes in Tanzania and North America.
Barthelona is a genus of anaerobic protists. They are basal eukaryotes closely related to skoliomonads, within the phylum Metamonada. It is a monotypic genus containing the sole species Barthelona vulgaris. Members of this genus are informally known as barthelonids.