Using biomineralized tissues to evaluate trophic structure of a Cretaceous ecosystem from Argentina

JO HELLAWELL, DANIEL G. POIRÉ, AUGUSTO N. VARELA AND CHRIS J. NICHOLAS

Birmingham, UK

Congreso; The Palaeontological Association 53rd Annual Meeting; 2009

University of Birmingham, UK

Using biomineralized tissues to evaluate trophic structure of a Cretaceous ecosystem from Argentina Jo Hellawell1, Daniel G. Poiré2, Augusto N. Varela2 and Chris J. Nicholas1 1, Daniel G. Poiré2, Augusto N. Varela2 and Chris J. Nicholas1 1Department of Geology, Trinity College, University of Dublin, Ireland Department of Geology, Trinity College, University of Dublin, Ireland 2Centro de Investigaciones Geológicas, UNLP- CONICET, La Plata, Argentina Centro de Investigaciones Geológicas, UNLP- CONICET, La Plata, Argentina Stable isotopes of nitrogen and organic carbon have been widely used in the evaluation and understanding of food webs in modern and archaeological ecosystems since the late 1970s. More recently, palaeontological studies of Tertiary lagerstätte have revealed that these stable isotopes can also provide trophodynamic information regarding ancient ecosystems when preserved soft tissues and organic components are analysed. Biomineralized tissues from vertebrate fossils have now been found to preserve an organic component retaining measurable amounts of nitrogen and organic carbon within their crystal lattices. The Mata Amarilla Formation in southern Patagonia contains numerous fragments of bones, scales and teeth from vertebrates of the Upper Cretaceous, thus presenting an exceptional opportunity to gain valuable insights into a much older, little known fossil community by using isotopic evidence. N and C isotope data were obtained for a variety of fish and reptiles from similar stratigraphic levels to allow trophic reconstruction. Inferences regarding food web structure from the stable isotope data were consistent with the ecology of the taxa as inferred from other criteria. The retrieval of this bulk isotopic data from hard biomineralized tissues opens up new possibilities for further palaeoecological assessments via this method for many ancient fossil communities.