Upper Ordovician chondrichthyan‐like scales from North America

@article{Andreev2015UpperOC,
  title={Upper Ordovician chondrichthyan‐like scales from North America},
  author={Plamen S. Andreev and Michael I. Coates and Richard Shelton and Paul Cooper and M. Paul Smith and Ivan J. Sansom},
  journal={Palaeontology},
  year={2015},
  volume={58}
}
Studies of Ordovician micromeric fish scales from the Sandbian of North America have identified a number of scale‐based taxa potentially referable to the chondrichthyans and therefore can be among the stratigraphically oldest representatives of the clade described to date. Two of these, Tezakia hardingensis gen. et sp. nov. and Canyonlepis smithae gen. et sp. nov., are formally described herein. Tezakia gen. nov. scales are composed exclusively of tubular dentine and possess polyodontocomplex… 

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