The oldest holocephalan (Chondrichthyes) from the Middle Devonian of the Boulonnais (Pas-de-Calais, France)

Laurent DARRAS, Claire DERYCKE, Alain R. M. BLIECK & Daniel VACHARD

en Comptes Rendus Palevol 7 (5) - Pages 297-304

Published on 31 July 2008

The Couderousse Member of the Blacourt Formation in the Banc-Noir quarry, Ferques inlier, Boulonnais (Pas-de-Calais, France) has yielded a tooth plate whose morphology is similar to that of Synthetodus, which is considered a holocephalan. Its histology is made of an outer enameloid-like tissue, and an inner trabecular dentine. Its occlusal surface shows a bean-shaped bulge. This tooth plate was prepared from a limestone that is dated from the Middle–Upper varcus Conodont Zone, that is lower upper Givetian. This limestone has also yielded a Pokorninella bricae–Rothpletzella–Tentaculites assemblage, which is indicative of an environment of the inner to middle marine platform boundary. This specimen appears to be the oldest confirmed holocephalan (‘bradyodont’) tooth plate for which the name Melanodus loonesi nov. gen. et sp. is erected.


Banc-Noir quarry, Ferques inlier, Blacourt Formation, Givetian, Trabecular dentine, New genus and species, France

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