Fossil Musculature of the Most Primitive Jawed Vertebrates

@article{Trinajstic2013FossilMO,
  title={Fossil Musculature of the Most Primitive Jawed Vertebrates},
  author={Kate Trinajstic and Sophie Sanchez and Vincent Dupret and Paul Tafforeau and John Long and Gavin Young and Timothy John Senden and Catherine A. Boisvert and Nicola Power and Per Erik Ahlberg},
  journal={Science},
  year={2013},
  volume={341},
  pages={160 - 164}
}
From Jawless to Jawed The earliest vertebrates were jawless. Past reconstructions have assumed that the primitive jawed condition was much like that found in sharks. Trinajstic et al. (p. 160, published online 13 June; see the Perspective by Kuratani) describe fossil musculature from the early jawed placoderms (an extinct class of armored prehistoric fish) that show that the basal structure was distinct from that found in sharks, having a notable dermal joint between the skull and shoulder… 
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