Multicuspid tooth morphology in a gigantic Palaeocene pycnodont fish : evolutionary and palaeoecological significance Article - Juillet 2019

Romain Vullo, Nathalie Bardet, Emmanuel Gheerbrant, Nour-Eddine Eddine Jalil

Romain Vullo, Nathalie Bardet, Emmanuel Gheerbrant, Nour-Eddine Eddine Jalil, « Multicuspid tooth morphology in a gigantic Palaeocene pycnodont fish : evolutionary and palaeoecological significance  », Geological Magazine, juillet 2019, pp. 1618 - 1622. ISSN 0016-7568

Abstract

A pycnodont premaxilla bearing a large incisiform tooth with an unusual crown morphology is described from the Palaeocene (Thanetian) phosphate deposits of Morocco. This peculiar tooth shows a broad, fan-shaped multicuspid crown with nine cusps, well adapted for benthic macroalgal scraping. This morph, assigned to a new species of Pycnodus (P. multicuspidatus sp. nov.), emphasizes the phenotypic plasticity of the group and documents an additional trophic specialization among Palaeogene pycnodontiform fishes. In the post-K/Pg boundary marine ecosystem of the Ouled Abdoun Basin, P. multicuspidatus sp. nov. may have opportunistically replaced Maastrichtian fish taxa with a similar front dentition and feeding behaviour, such as the putative specialized pycnodontiforms Stephanodus and Hadrodus.

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