English: Evolution of the now extinct placoderms fishes during the Devonian and the early Carbonifereous as a spindle diagram. The width of the spindles are proportional to the number of families as a rough estimate of diversity.
The diagram is based on Benton, M. J. (2005) Vertebrate Palaeontology, Blackwell, 3rd edition, Fig 3.25 on page 73.
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