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The evolution of jaws was a crucial step in vertebrate history, but
it took place so long ago that fossils from this period consist
mostly of teeth and a bewildering variety of skin scales. Now an
almost complete shark fossil gives paleontologists the opportunity
to investigate the poorly understood transition between sharks and
modern fishes and to interpret isolated fossils from a new
perspective. The remarkably intact 409 million year-old example
preserves the braincase, jaws, teeth and pectoral fins in the
correct anatomical position. Based on this finding, the authors
revise the geography of early shark evolution and question the
accepted picture of shark evolution as it relates to other major
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