Actinistia

plural noun
Ac·​ti·​nis·​tia | \ˌak-tə-ˈni-stē-ə\

Definition of Actinistia 

: an order (superorder Crossopterygii) of chiefly Mesozoic fishes including the family Coelacanthidae having the interspinous bones supporting each dorsal and anal fin fused into one piece — compare latimeria

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First Known Use of Actinistia

1871, in the meaning defined above

History and Etymology for Actinistia

New Latin, from actin- + -istia (from Greek histion web, cloth, sail); akin to Greek histos mast, weaver's beam, web

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The first known use of Actinistia was in 1871

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