A large accumulation of avian eggs from the Late Cretaceous of Patagonia (Argentina) reveals a novel nesting strategy in Mesozoic birds

Fernández, Mariela.; Garcia, Rodolfo A.; Fiorelli, Lucas E.; Scolaro, Jose A.; Salvador, Rodrigo B.; Cotaro, Carlos N.; Kaiser, Gary W.; Dyke, Gareth J.
Publication Year
Published version
Fil: Fernández, Mariela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte; Argentina
Fil: Fernández, Mariela. Instituto de Investigación en Biodiversidad y Medioambiente; Argentina
Fil: Garcia, Rodolfo A. Universidad Nacional de Rio Negro. Sede Alto Valle; Argentina
Fil: Garcia, Rodolfo A. Instituto de Investigaciones En Paleobiologia y Geologia; Argentina
Fil: Fiorelli, Lucas E. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Fiorelli, Lucas E. Centro Regional de Investigaciones Cientificas y Transferencia Tecnológica de Anillaco; Argentina
Fil: Scolaro, Jose A. Universidad Nacional de la Patagonia "san Juan Bosco"; Argentina.
Fil: Scolaro, Jose A. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina
Fil: Salvador, Rodrigo B. Universidade de Sao Paulo. Instituto Quã­mica de Sao Carlos; Brasil
Fil: Cotaro, Carlos N. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina
Fil: Kaiser, Gary W. Royal British Columbia Museum; Canadá
Fil: Dyke, Gareth J. University Of Southampton; Reino Unido
We report the first evidence for a nesting colony of Mesozoic birds on Gondwana: a fossil accumulation in Late Cretaceous rocks mapped and collected from within the campus of the National University of Comahue, Neuquén City, Patagonia (Argentina). Here, Cretaceous ornithothoracine birds, almost certainly Enanthiornithes, nested in an arid, shallow basinal environment among sand dunes close to an ephemeral water-course. We mapped and collected 65 complete, near-complete, and broken eggs across an area of more than 55 m2. These eggs were laid either singly, or occasionally in pairs, onto a sandy substrate. All eggs were found apparently in, or close to, their original nest site; they all occur within the same bedding plane and may represent the product of a single nesting season or a short series of nesting attempts. Although there is no evidence for nesting structures, all but one of the Comahue eggs were half-buried upright in the sand with their pointed end downwards, a position that would have exposed the pole containing the air cell and precluded egg turning. This egg position is not seen in living birds, with the exception of the basal galliform megapodes who place their eggs within mounds of vegetation or burrows. This accumulation reveals a novel nesting behaviour in Mesozoic Aves that was perhaps shared with the non-avian and phylogenetically more basal troodontid theropods.
Nesting Colony
Late Cretaceous
.::Ciencias Exactas y Naturales::Ciencias Ambientales y de la Tierra::Paleontología
Access level
Open access
Universidad Nacional de Río Negro
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