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.
These example sentences are selected automatically from various online news sources to reflect current usage of the word 'radiolarian.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
First Known Use of radiolarian
Learn More about radiolarian
Britannica.com: Encyclopedia article about radiolarian
Seen and Heard
What made you want to look up radiolarian? Please tell us where you read or heard it (including the quote, if possible).