Late Triassic sharks teeth (Chondrichthyes, Elasmobranchii) from Saint-Nicolas-de-Port (north-east France)
Duffin, C.J. (1993). Late Triassic sharks teeth (Chondrichthyes, Elasmobranchii) from Saint-Nicolas-de-Port (north-east France), in: Herman, J.S. et al. Elasmobranches et stratigraphie. Professional Paper. Geological Survey of Belgium, 1993/06(264): pp. 7-32
In: Herman, J.S.; Van Waes, H (1993). Elasmobranches et stratigraphie. Professional Paper. Geological Survey of Belgium, 1993/06(264). Geologische Dienst van België: Brussel. 260 pp., 55 figs., 42 p pp., more
In: Professional Paper. Geological Survey of Belgium. Belgische Geologische Dienst: Brussel. ISSN 0378-0902, more
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Document type: Scientific report
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| Keywords |
Geological time > Phanerozoic > Geological time > Mesozoic > Triassic > Triassic, Upper > Norian
Chondrichthyes [WoRMS]
France, Lorraine [Marine Regions]
Marine/Coastal |
| Author keywords |
Chondrichthyes - Elasmobranchii - Neoselachii - teeth - new taxon - enameloid - Lissodus - age |
| Abstract |
Isolated fossil sharks teeth from Saint-Nicolas-de-Port, near Nancy in north-east France are described as Rhomphaiodon nicolensis gen. et sp. nov. The teeth most closely resemble those of Hybodus minor AGASSIZ. A high central cusp is flanked by up to three pairs of lateral cusplets. Ontogenetic changes in the dentition include decrease in height of the lateral cusplets relative to the central cusp. Monognathic heterodonty includes increase in crown asymmetry and central cusp inclination, plus lowering of the crown profile posteriorly through the dentition. The teeth have a unique triple-layered enameloid; a surface layer of shiny enameloid is underlain by a parallel-fibred enameloid, beneath which is a single crystallite layer. The enameloid ultrastructure indicates neoselachian affinity, while tooth architecture resembles that of hybodonts. The fauna also contains teeth of Lissodus minimus (AGASSIZ). Faunal comparisons support the suggestion by previous authors that the Saint-Nicolas-de-Port succession is at least partly equivalent to the Knollenmergel (Norian, Late Triassic). |
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