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cros·sop·ter·yg·ian | \ ˌkrȯ-ˌsäp-tə-ˈri-j(ē-)ən 
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\Definition of crossopterygian
: any of a subclass (Crossopterygii) of bony fishes (such as a coelacanth) that have paired fins suggesting limbs, that may be ancestral to the terrestrial vertebrates, and that are mostly extinct
— called also lobe-fin
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Time Traveler for crossopterygian
The first known use of crossopterygian was in 1861
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