The phyllolepid placoderm Cowralepis mclachlani: Insights into the evolution of feeding mechanisms in jawed vertebrates

@article{Carr2009ThePP,
  title={The phyllolepid placoderm Cowralepis mclachlani: Insights into the evolution of feeding mechanisms in jawed vertebrates},
  author={Robert K. Carr and Zerina Johanson and Alexander Ritchie},
  journal={Journal of Morphology},
  year={2009},
  volume={270}
}
Remarkably preserved specimens of Cowralepis mclachlani Ritchie, 2005 (Proc Linn Soc NSW 126:215–259) (Phyllolepida, Placodermi) represent a unique ontogenetic sequence adding to our understanding of anatomy, function, and phylogeny among basal jawed vertebrates (gnathostomes). A systematic review demonstrates that the Phyllolepida are a subgroup of the Arthrodira. Consideration of visceral and neurocranial characters supports the hypothesis that placoderms are the sister group to remaining… 

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Placoderm anatomy any phylogeny: new insights

TLDR
It is proposed that two median dorsal plates may be primitive for placoderms, this being the defining difference to the osteichthyan shoulder girdle in creating a rigid ring of bones for the placoderm dermal neckjoint.
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