Mariela S. Fernández, Rodolfo
A. García, Lucas Fiorelli, Alejandro Scolaro, Rodrigo B. Salvador, Carlos
N. Cotaro, Gary W. Kaiser y Gareth J. Dyke
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, nearcomplete, 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.
Fernández MS, García RA, Fiorelli
L, Scolaro A, Salvador RB, et al. (2013) A Large Accumulation of Avian Eggs
from the Late Cretaceous of Patagonia (Argentina) Reveals a Novel Nesting
Strategy in Mesozoic Birds. PLoS ONE 8(4): e61030.
doi:10.1371/journal.pone.0061030
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