Radiolaria

Radiolaria Temporal range: Cambrian – Recent PreꞒ Ꞓ O S D C P T J K Pg N
Radiolaria illustration from the Challenger expedition 1873–76
Scientific classification
Domain:	Eukaryota
Clade:	Diaphoretickes
Clade:	SAR
Phylum:	Retaria
Subphylum:	Radiolaria Cavalier-Smith, 1987
Classes
Polycystinea Nassellaria Spumellaria Collodaria Acantharea Taxopodida (Sticholonche) Excluded: Phaeodaria (now in Cercozoa)

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Plankton
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By size Heterotrophic picoplankton Microalgae Microzooplankton Nanophytoplankton calcareous Photosynthetic picoplankton Picoeukaryote Picoplankton Marine microplankton
By taxonomy Algae diatoms coccolithophores dinoflagellates Protozoans radiolarians foraminiferans amoebae ciliates Bacteria cyanobacteria Archaea Viruses
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Blooms Algal bloom Critical depth Cyanobacterial bloom Harmful algal bloom Spring bloom Eutrophication Great Atlantic Sargassum Belt Great Calcite Belt Milky seas effect
Related topics Algaculture CLAW hypothesis CPR Diel vertical migration f-ratio Marine primary production Ocean fertilization iron Paradox of the plankton Planktivore Planktology Thin layers NAAMES
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The Radiolaria, also called Radiozoa, are protozoa of diameter 0.1–0.2 mm that produce intricate mineral skeletons, typically with a central capsule dividing the cell into the inner and outer portions of endoplasm and ectoplasm. The elaborate mineral skeleton is usually made of silica.^[1] They are found as zooplankton throughout the global ocean. As zooplankton, radiolarians are primarily heterotrophic, but many have photosynthetic endosymbionts and are, therefore, considered mixotrophs. The skeletal remains of some types of radiolarians make up a large part of the cover of the ocean floor as siliceous ooze. Due to their rapid change as species and intricate skeletons, radiolarians represent an important diagnostic fossil found from the Cambrian onwards.