''Skeletonema'' is a genus of centric

diatom A diatom (Neo-Latin ''diatoma'') is any member of a large group comprising several Genus, genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. Living diatoms make up a significant portion of Earth's B ...

s in the family

Skeletonemataceae Skeletonemataceae is a family of centric diatoms in the order Thalassiosirales. There is currently only one living and one fossil genus in this family. Their sexual reproduction is oogamous Oogamy is a form of anisogamy where the gametes diffe ...

. It is the

type genus In biological taxonomy, the type genus (''genus typica'') is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearin ...

of its family.

Background

Diatoms are

photosynthetic Photosynthesis ( ) is a Biological system, system of biological processes by which Photoautotrophism, photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical ener ...

organisms, meaning they obtain carbon dioxide from their surrounding environment and produce oxygen along with other byproducts. They reproduce sexually (sexual reproduction is

oogamous Oogamy is a form of anisogamy where the gametes differ in both size and form. In oogamy the large female gamete (also known as ovum) is immotile, while the small male gamete (also known as spermatozoon) is mobile. Oogamy is a common form of anis ...

) and asexually. ''Skeletonema'' belong to the morphological category referred to as centric diatoms. These are classified by having valves with radial symmetry and the cells lack significant motility.A Taxonomic Guide to Some Common Marine Phytoplankton: Rita A. Horner, Biopress Limited, The Orchard, Clanage Road, Bristol, BS3 2JX, England, 2002, 195 pp.

Taxonomy

The genus ''Skeletonema'' was established by

Robert Kaye Greville Dr. Robert Kaye Greville FRSE FLS LLD (13 December 1794 – 4 June 1866) was an England, English mycologist, bryology, bryologist, and botanist. He was an accomplished artist and illustrator of natural history. In addition to art and scien ...

in 1865 for a single fossil species, ''S.'' ''barbadense'' (now ''Skeletonemopsis barbadense''), found in

Barbados Barbados, officially the Republic of Barbados, is an island country in the Atlantic Ocean. It is part of the Lesser Antilles of the West Indies and the easternmost island of the Caribbean region. It lies on the boundary of the South American ...

deposits. The genus has a new extant

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

: '' S.'' '' costatum''.

Morphology and ultrastructure

''Skeletonema'' are cylindrical shaped with a silica

frustule A frustule is the hard and porous cell wall or external layer of diatoms. The frustule is composed almost purely of silica, made from silicic acid, and is coated with a layer of organic substance, which was referred to in the early literature on ...

. Cells are joined by long marginal processes to form a filament. Their length ranges from 2-61 micrometers, with a diameter ranging from 2-21 micrometers.

Ecology and distribution

They are found typically in the neritic zone of the ocean and are highly populous in coastal systems. The genus is considered

cosmopolitan Cosmopolitan may refer to: Internationalism * World citizen, one who eschews traditional geopolitical divisions derived from national citizenship * Cosmopolitanism, the idea that all of humanity belongs to a single moral community * Cosmopolitan ...

, showing a wide range of tolerance for salinity and temperature. For example, they have been found in various aquatic environments such as

brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...

or freshwater. ''Skeletonema'' are found worldwide excluding

Antarctic The Antarctic (, ; commonly ) is the polar regions of Earth, polar region of Earth that surrounds the South Pole, lying within the Antarctic Circle. It is antipodes, diametrically opposite of the Arctic region around the North Pole. The Antar ...

waters. Some species are found in both the northern and southern temperate latitudes whereas other species appear to have only subtropical to tropical ranges. Some harmful effects these diatoms may have on an ecosystem are attributed to large blooming events which may cause hypoxic events in coastal systems. Additionally, they are known to cause water discoloration.

References

External links

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''Skeletonema''
at WoRMS Thalassiosirales Diatom genera {{Diatom-stub Taxa described in 1865