''Stauridium'' 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 ...

green algae The green algae (: green alga) are a group of chlorophyll-containing autotrophic eukaryotes consisting of the phylum Prasinodermophyta and its unnamed sister group that contains the Chlorophyta and Charophyta/ Streptophyta. The land plants ...

in the family

Hydrodictyaceae Hydrodictyaceae is a family of green algae in the order Sphaeropleales. They are found in freshwater habitats worldwide. Members of this family are either unicellular or colonial. Cells are cylindrical, polyhedral, spherical, or sometimes nearly ...

.See the

NCBI The National Center for Biotechnology Information (NCBI) is part of the National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the government of the United States. The NCBI is loca ...

br>webpage on Stauridium
Data extracted from the It is very common in freshwater regions throughout the world.

Description

''Stauridium'' forms flat colonies, termed coenobia, of cells in powers of two, usually four, eight, or 16. Coenobia are disc-shaped in outline, composed of cells laid contiguously next to each other with no spaces in between cells. The marginal cells are trapezoidal, with (in '' S. tetras'') or without (in '' S. privum)'' a V-shaped incision in the middle. The cell wall is smooth or covered in granules, warts, or ridges. Cells have one

chloroplast A chloroplast () is a type of membrane-bound organelle, organelle known as a plastid that conducts photosynthesis mostly in plant cell, plant and algae, algal cells. Chloroplasts have a high concentration of chlorophyll pigments which captur ...

filling the cell, each with a single

pyrenoid Pyrenoids are sub-cellular phase-separated micro-compartments found in chloroplasts of many algae,Giordano, M., Beardall, J., & Raven, J. A. (2005). CO2 concentrating mechanisms in algae: mechanisms, environmental modulation, and evolution. ''An ...

. Species of ''Stauridium'' have thin cell walls, so they tend not to preserve well in sediments.

Taxonomy

Although ''Stauridium'' was first described by

August Carl Joseph Corda August Carl Joseph Corda (15 November 1809 – 1849) was a physician, botanist, and mycologist from Bohemia. This botanist is denoted by the List of botanists by author abbreviation, author abbreviation Corda when Author citation (botany), citing ...

in 1839, for most of its history it was considered to be a synonym of ''

Pediastrum ''Pediastrum'' is a genus of green algae, in the family Hydrodictyaceae. It is a photoautotrophic, nonmotile coenobial green alga that inhabits freshwater environments. The name ''Pediastrum'' comes from the Greek root words ''pedion'', meaning ...

''. In 2005,

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

analyses showed that ''Pediastrum'' ''

sensu lato ''Sensu'' is a Latin word meaning "in the sense of". It is used in a number of fields including biology, geology, linguistics, semiotics, and law. Commonly it refers to how strictly or loosely an expression is used in describing any particular co ...

'' was

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

with respect to ''

Hydrodictyon The water net (genus ''Hydrodictyon'') is a taxon of freshwater green algae in the family Hydrodictyaceae. ''Hydrodictyon'' does well in clean, eutrophic water, and has become a nuisance in New Zealand, where it has been recently introduced. The ...

''. Therefore, ''Pediastrum'' was split up into several genera, including ''Stauridium''.

References

Sphaeropleales genera Sphaeropleales {{Chlorophyceae-stub