Early Jawless Vertebrates and Cyclostome Origins

@inproceedings{Janvier2008EarlyJV,
  title={Early Jawless Vertebrates and Cyclostome Origins},
  author={Philippe Janvier},
  booktitle={Zoological science},
  year={2008}
}
  • P. Janvier
  • Published in Zoological science 2008
  • Biology, Medicine
Abstract Undoubted fossil lampreys are recorded since the Late Devonian (358 Ma), and probable fossil hagfishes since the Late Carboniferous (300 Ma), but molecular clock data suggest a much earlier divergence times for the two groups. In the early 20th century, hagfishes and lampreys were generally thought to have diverged much later from unknown ancestral cyclostomes, in turn derived through ‘degeneracy’ from some Paleozoic armored jawless vertebrates, or ‘ostracoderms.’ However, current… Expand
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TLDR
By addressing nonindependence of characters, phylogenetic analyses recovered hagfish and lampreys in a clade of cyclostomes (congruent with the cyclostome hypothesis) using only morphological data, which potentially resolve the morphological–molecular conflict at the base of the Vertebrata. Expand
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  • P. Janvier
  • Biology, Medicine
  • Proceedings of the National Academy of Sciences
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Palaeospondylus as a primitive hagfish
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