Correlated progression and the origin of turtles

@article{Lee1996CorrelatedPA,
  title={Correlated progression and the origin of turtles},
  author={Michael S. Y. Lee},
  journal={Nature},
  year={1996},
  volume={379},
  pages={812-815}
}
TURTLES exhibit some of the most extreme postcranial modifications found in vertebrates. The dorsal vertebrae and ribs have fused with dermal armour, forming a totally rigid box-like trunk region1,2 Our understanding of chelonian origins has been restricted by a paucity of information on intermediate forms3,4, however, and it is often assumed that they must have evolved saltationally5. It has been suggested that pareiasaurs, a group of large herbivorous anapsid reptiles, are the sister-group of… 

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The Origin and Early Evolution of Turtles Author ( s ) :

■ Abstract A critical reexamination of turtle relationships continues to support a sister-group relationship of turtles with a clade of marine reptiles, Sauropterygia, within crown-group Diapsida
...

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