Skoliomonas is a genus of anaerobic closely related to , a small group of basal 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.
Etymology
The name
Skoliomonas derives , 'crooked', which refers to the hunched appearance of the cell and the twisted venral groove, and
μονάς (monas) 'unit', a common suffix used for unicellular protists. The
specific epithet litria comes , an alternative form of
νίτρον (nitron), meaning
sodium carbonate; the term was used by
Herodotus to describe embalming salts used for mummification in
Ancient Egypt, harvested from carbonate-rich soda lakes of the
Natron Valley. The authors of the species chose the African-specific version of the Ancient Greek word to reflect the African type locality and the possible relevance of these alkaline lakes to local human culture and history.
Description
Skoliomonads are
,
unicellular (a type of
eukaryote) that use
flagella for movement. Their cells are rounded at their anterior end and pointy at their posterior, with a flattened ventral side and a dorsal hump. The ventral side contains a major groove, which is characteristic of other basal eukaryotes such as
excavata. The cells are asymmetrical: the left side of the cell contains the majority of the
cytoplasm, including the
cell nucleus and various large
for digestion, often containing
bacteria which constitute their
prey. The right side is occupied almost entirely by the right edge of the groove. The type isolate, TZLM3-RCL, has been observed forming complex
microbial cyst with two walls and a conspicuous plugged pore, something unique among metamonads.
Each cell has two flagella of different lengths, inserted sub-apically and facing the ventral side of the cell. A conspicuous "lip" structure extends from the flagellar insertion along the right side of the ventral groove to the base of the posterior pointy end. The anterior flagellum is around the same length as the cell, and it is pointed forward. The posterior flagellum is twice as long, and features a conspicuously broad flagellar vane around 1 μm wide along the length of the groove, directed away from the cell body.
The ventral groove curves gently to the right as it extends down the cell, and its posterior end has a large opening that gives way to a large cytopharynx underneath its right edge. The cytopharynx, supported by a robust intracellular structure, extends along the dorsal side toward the cell's anterior apex. This is unique to skoliomonads and , since the cytopharynx of most known ( Carpediemonas-like organisms) is short, discrete and points toward the left side of the cells. Skoliomonads are similar to most other metamonads in their big flagellar vane, which barthelonids lack.
Ecology
Skoliomonads are
anaerobe microorganisms that feed on
bacteria. In particular,
Skoliomonas litria is a haloalkaliphilic anaerobe, as it inhabits a hypersaline and alkaline
soda lake.
Taxonomy
The
genus Skoliomonas was described by
Yana Eglit and Alastair G.B. Simpson, from strains of metamonad flagellates isolated from alkaline hypersaline sediments found at various
:
Lake Manyara in
Tanzania,
Goodenough Lake in
British Columbia, Canada, and
Soap Lake in
Washington state, USA. The isolates were cultivated, observed under
light microscopy and transmission electron microscopy, and
DNA sequencing in order to discover their phylogenetic position. Following the results, the authors published in 2024 the description of this genus, along with its
type species and only
species Skoliomonas litria.
In phylogenetic analyses using the SSU rRNA gene, a clade composed of Skoliomonas isolates, informally named "skoliomonads", is the sister group to , which are in turn closely related to Fornicata within the phylum Metamonada.
Citations
Cited literature
External links
