title: Isotopic and anatomical evidence of an herbivorous diet in the Early Tertiary giant bird Gastornis. implications for the structure of Paleocene terrestrial ecosystems.
abstract: The mode of life of the early Tertiary giant bird Gastornis has long been a matter of controversy. Although it has often been reconstructed as an apex predator feeding on small mammals, according to other interpretations, it was in fact a large herbivore. To determine the diet of this bird, we analyze here the carbon isotope composition of the bone apatite from Gastornis and contemporaneous herbivorous mammals. Based on (13)C-enrichment measured between carbonate and diet of carnivorous and herbivorous modern birds, the carbonate δ(13)C values of Gastornis bone remains, recovered from four Paleocene and Eocene French localities, indicate that this bird fed on plants. This is confirmed by a morphofunctional study showing that the reconstructed jaw musculature of Gastornis was similar to that of living herbivorous birds and unlike that of carnivorous forms. The herbivorous Gastornis was the largest terrestrial tetrapod in the Paleocene biota of Europe, unlike the situation in North America and Asia, where Gastornis is first recorded in the early Eocene, and the largest Paleocene animals were herbivorous mammals. The structure of the Paleocene terrestrial ecosystems of Europe may have been similar to that of some large islands, notably Madagascar, prior to the arrival of humans.
authors.affiliation: UMR 5276 Laboratoire de Géologie de Lyon, Terre, Planètes et Environnement, Université Claude Bernard Lyon 1 / CNRS / Ecole Normale Supérieure de Lyon, 69622, Villeurbanne Cedex, France, angst.delphine@gmail.com.
authors.forename: D
authors.initials: D
authors.lastname: Angst
authors.forename: C
authors.initials: C
authors.lastname: Lécuyer
authors.forename: R
authors.initials: R
authors.lastname: Amiot
authors.forename: E
authors.initials: E
authors.lastname: Buffetaut
authors.forename: F
authors.initials: F
authors.lastname: Fourel
authors.forename: F
authors.initials: F
authors.lastname: Martineau
authors.forename: S
authors.initials: S
authors.lastname: Legendre
authors.forename: A
authors.initials: A
authors.lastname: Abourachid
authors.forename: A
authors.initials: A
authors.lastname: Herrel
mesh_terms: D000818:Animals; D001717:Birds / Q000502:physiology*; D001842:Bone and Bones / Q000737:chemistry; D002250:Carbon Radioisotopes / Q000032:analysis; D004032:Diet; D017753:Ecosystem; D005580:Fossils; D060434:Herbivory
chemical_list: D002250:Carbon Radioisotopes