Definition of radiolarian
: any of three classes (Acantharia, Polycystina, and Phaeodaria) of usually spherical chiefly planktonic marine protozoans having radiating threadlike pseudopodia and often a siliceous skeleton of spicules
Recent Examples of radiolarian from the Web
The organic carbon decline coincided with the disappearance of more than 50 species of radiolarians, which served as a food source for numerous marine species and whose disappearance was an indicator of a major biological crisis.
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First Known Use of radiolarian
Learn More about radiolarian
Britannica.com: Encyclopedia article about radiolarian
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