Evolution and development of the synarcual in early vertebrates

  title={Evolution and development of the synarcual in early vertebrates},
  author={Zerina Johanson and Kate Trinajstic and Robert K. Carr and Alexander Ritchie},
The synarcual is a structure incorporating the anterior vertebrae of the axial skeleton and occurs in vertebrate taxa such as the fossil group Placodermi and the Chondrichthyes (Holocephali, Batoidea). Although the synarcual varies morphologically in these groups, it represents the first indication, phylogenetically, of a differentiation of the vertebral column into separate regions. Among the placoderms, the synarcual of Cowralepismclachlani Ritchie, 2005 (Arthrodira) shows substantial changes… 

Phenotypic regionalization of the vertebral column in the thorny skate Amblyraja radiata: Stability and variation

Micro‐computed tomography scans of vertebral columns of a growth series of thorny skates Amblyraja radiata are used to provide the first fine‐scale morphological description of vertebra units in a batoids species and axial regionalization is investigated using a replicable clustering analysis on presence/absence of vertebrate elements to decipher the regionalization of the vertebral column of A. radiata.



The synarcual cartilage of batoids with emphasis on the synarcual of Rajidae

Comparison of embryonic specimens with juvenile and mature specimens of other skates indicates that the relative developmental sequence of events is maintained among several taxa within larger clades, and results from exploratory analyses of morphospace and taxonomy reveal that phylogeny explains part, but not all, of the data on the synarcual in Rajidae.

Les arthrodires du Dévonien supérieur du Tafilalet

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The systematics of the stingray genus Urotrygon with comments on the interrelationships within Urolophidae Chondrichthyes, Myliobatiformes)

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Cowralepis, a new genus of phyllolepid fish (Pisces, Placodermi) from the Late Middle Devonian of New South Wales, Australia

The Cowralepis material has suffered regional tectonism and illustrates why tectonic deformation must be taken into account in the interpretation of fossils from ancient fold belts.

A (2010) Vertebral development

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Placoderm interrelationships reconsidered in the light of new ptyctodontids from Gogo , Western Australia

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Vertebral development in the gnathostome stem group ( Placodermi ) : fusion , gene misexpression , and homeotic transformations

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The Plagiostoma (sharks, skates, and rays)

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