Small marine and freshwater jawed fish that appeared first in the Early Silurian.
Had stout spines that supported paired fins.
Had scales rather than bony plates.
Had cartilaginous skeletons.
Became extinct near the end of the Paleozoic.
Share an ancestor with today’s bony fishes.
Image courtesy of Stanton Fink.
Acanthodians from Early Devonian Britain: Mesacanthus pusillus (top), Parexus falcatus and Ishnacanthus gracilis. ►