Definition of lobe-finned fish in US English:

lobe-finned fish

(also lobefin)

noun

  • A fish of a largely extinct group having fleshy lobed fins, including the probable ancestors of the amphibians.

    Subclass Crossopterygia (or Actinistia or Coelacanthimorpha): the only living representative is the coelacanth

    Compare with ray-finned fish
    • ‘Among fish, the armoured placoderm and ostracoderm and marine lobe-finned fish (apart from the odd coelacanths) that so dominated the Devonian seas are all gone, to be replaced by an amazing diversity of sharks (Chondrichthyes).’
    • ‘This latter species belonged to an endemic group of lobefins that we named the canowindrids, after the genus Canowindra, coincidentally named after its locality, the town of Canowindra in New South Wales.’
    • ‘The lobe-finned fish possessed lungs as well as gills.’
    • ‘In the living lobe-finned fish (lungfish and coelacanths) the tail is now symmetric, though the fossil record shows that this change happened independently in the two groups.’
    • ‘According to Hedges, by about 360 million years ago the transition of lobe-finned fish - prehistoric fish with fleshy fins - to four-limbed tetrapods was nearly complete.’