radiolarian

American  

[rey-dee-oh-lair-ee-uhn] / ˌreɪ di oʊˈlɛər i ən /

noun

1. any minute, marine protozoan of the class Radiolaria, or, in some classification schemes, the superclass Actinopoda, having an amebalike body with radiating, filamentous pseudopodia and a usually elaborate outer skeleton.

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radiolarian British  

/ ˌreɪdɪəʊˈlɛərɪən /

noun

1. any of various marine protozoans constituting the order Radiolaria , typically having a siliceous shell and stiff radiating cytoplasmic projections: phylum Actinopoda (actinopods)

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radiolarian Scientific  

/ rā′dē-ō-lâr′ē-ən /

1. Any of various marine protozoans of the group Radiolaria, having rigid skeletons usually made of silica. The skeletons are usually spherically symmetrical and structurally complex, containing elaborate patterns of perforations (through which pseudopods extend) and often spicules. Skeletal remains of radiolarians sink to form ooze on the ocean floor, and prehistoric radiolarian ooze has fossilized to become chert and flint.

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Etymology

Origin of radiolarian

1875–80; < New Latin Radiolari ( a ) name of the group ( Latin radiol ( us ) a small beam, equivalent to radi ( us ) radius + -olus -ole ¹ + -aria -aria ) + -an

Example Sentences

And Sirjana correctly spelled puerilely — childish — and radiolarian — a single-celled marine animal having a spherical body with threadlike projections.

From Seattle Times • May 31, 2022

The shells of deceased diatoms and some radiolarian skeletons are also made of silicon dioxide.

From Scientific American • Apr. 15, 2013

When they die, their silicic, spherical skeletons sink to the ocean floor, form a radiolarian ooze.

From Time Magazine Archive

Lower Cretaceous limestones and schists, with radiolarian cherts, arc extensively developed; and in many parts of the island Upper Cretaceous limestones with Rudistes and Eocene beds with nummulites have been found.

From Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 6 "Coucy-le-Château" to "Crocodile" by Various

The simplest form of all exemplifies spherical symmetry, and is that which we have seen in the truffle, the radiolarian, the volvox, Myxastrum and Magosphæra.

From The Contemporary Review, Volume 36, October 1879 by Various