Unbalanced food web in a Late Cretaceous dinosaur assemblage

Article Article scientifique Article Unbalanced food web in a Late Cretaceous dinosaur assemblage eng 2013 author Läng Emilie author Boudad Larbi author Maio Laszlo 676165 author Samankassou Elias 0000-0003-0385-7686 636960 author Tabouelle Jérôme author Tong Haiyan author Cavin Lionel 26-32 10.1016/j.palaeo.2013.04.011 0031-0182 http://linkinghub.elsevier.com/retrieve/pii/S0031018213001855 The rich assemblage of continental vertebrates from the Cenomanian Kem Kem Beds (Morocco) is one of the best known and most diversified for themid Cretaceous period (Cenomanian). This assemblage, however, shows apparent ecological oddities, in particular the overabundance of theropod dinosaurs versus plant-eating dinosaurs. Several hypotheses have been proposed to explain this unbalanced ratio, including a peculiar ecosystem, non-systematic collecting, taphonomic factors, stratigraphic uncertainties and/or behavioral aspects of the dinosaur groups concerned. Except the comparison of proportions of taxa between field and shop data (McGowan and Dyke, 2009), the other hypotheses have not been tested so far because of the lack of accurately measured sections and systematically collected field data. Based on new field data, we test the above-mentioned hypotheses. The analysis is focused on the ratio of plant-eating versus carnivorous dinosaurs. This dataset confirms the unbalanced ratio; moreover, the stratigraphic distribution of fossils is quantitatively not homogeneous and consequently important to avoid time-averaging, i.e. the mixing of fossils of different ages together into a single unit. The origin of the unbalanced food web among dinosaurs is related neither to non-systematic collecting, nor to stratigraphic biases. The palaeoenvironment seems to be the only likely factor to explain the significantly high proportion of carnivorous versus plant-eating dinosaurs. Indeed, the deltaic palaeoenvironment offered unfavourable conditions for the setting of stable terrestrial vegetation but favouring aquatic life. This aquatic life formed the basic level of an aquatic or semi-aquatic foodweb,which directly fed top predators, such as theropods in general and spinosaurs in particular. Predator/prey ratio Dinosaurs Palaeoenvironment Cenomanian Kem Kem Beds Morocco Dewey 550 Swiss National Science Foundation FNS N° 146868 CH 142 Département de géologie et de paléontologie 151 42 Département des sciences de la Terre 154 false 671 Sedimentology, Biostratigraphy and Micropaleontology Palaeogeography, palaeoclimatology, palaeoecology 381-382 4d7abb09-4422-4b5b-8cf8-10a5653a01ac Article (Published version) Restricted Läng et al 2013 - Unbalanced food web, LK, Kem Kem Morocco.pdf 796822 application/pdf restrictedAccess Faculté des sciences / Section des sciences de la Terre et de l'Environnement / Département de géologie et de paléontologie Faculté des sciences / Section des sciences de la Terre et de l'Environnement / Département des sciences de la Terre

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Unbalanced food web in a Late Cretaceous dinosaur assemblage	Palaeogeography, palaeoclimatology, palaeoecology			2013	835	0

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