Oryctos
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Accès privé :
| volume 1, 1998 |
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Gilles Cuny, Primitive neoselachian sharks : a survey. Oryctos 1, 3-21.
A study of the ultrastructure of the enameloid of isolated teeth demonstrates that the neoselachian sharks, characterized by a triple-layered enameloid, radiated just after the Carnian, at the same time as some "experimental", poorly known sharks (Vallisia, Raineria, Pseudodalatias and Doratodus). Most of the Triassic neoselachian teeth share a hybodont-like architecture of the crown and a well-developed lingual torus in the root. These latter can be traced back at least in the Early Triassic. The clade Eunemacanthus + Amelacanthus + Hopleacanthus + Acronemus + Neoselachii may have appeared as far back as the Carboniferous. Isolated Palaeozoic teeth belonging to Mcmurdodus and Anachronistes may not belong to neoselachian sharks. Most likely, these isolated teeth represent the result of a convergence phenomenon in tooth morphology and vascularisation.
Keywords: Neoselachii, early evolution, Palaeozoic, Triassic, enameloid ultrastructure.
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