Dinosaur egg colour had a single evolutionary origin

  title={Dinosaur egg colour had a single evolutionary origin},
  author={Jasmina Wiemann and Tzu-Ruei Yang and Mark A. Norell},
Birds are the only living amniotes with coloured eggs1–4, which have long been considered to be an avian innovation1,3. A recent study has demonstrated the presence of both red-brown protoporphyrin IX and blue-green biliverdin5—the pigments responsible for all the variation in avian egg colour—in fossilized eggshell of a nonavian dinosaur6. This raises the fundamental question of whether modern birds inherited egg colour from their nonavian dinosaur ancestors, or whether egg colour evolved… 
The first dinosaur egg was soft
Molecular analyses of newly discovered, embryo-bearing ornithischian and sauropod dinosaur eggs suggest that the ancestral dinosaur egg was soft- shelled, and that hard-shelled eggs evolved independently at least three times in the major dinosaur lineages.
Temperature drives the evolution and global distribution of avian eggshell colour
Evidence is shown that darker and browner eggs have indeed evolved in cold climes, and that the thermoregulatory advantage for avian eggs is a stronger selective pressure in cold climates.
Comparative crystallography suggests maniraptoran theropod affinities for latest Cretaceous European ‘geckoid’ eggshell
Thin fossil eggshell from Upper Cretaceous deposits of Europe, characterized by nodular ornamentation similar to modern gekkotan eggshell, has mostly been interpreted as gekkotan (=‘geckoid’) in
Recent advances in amniote palaeocolour reconstruction and a framework for future research
This review focused on fossil amniotes produces an overarching framework that appropriately reconstructs palaeocolour by accounting for the chemical signatures of various pigments, morphology and local arrangement of pigment‐bearing vesicles, pigment concentration, macroscopic colour patterns, and taphonomy.
Individuality in Egg Colouration of Black-Headed Gulls Chroicocephalus ridibundus across the Years Confirmed through DNA Analyses
Black-headed Gulls showed consistent individual-specific eggshell colour pattern across consecutive breeding seasons, which strongly suggest colour variation is driven by internal rather than external factors in this colonially breeding species.
Morphological research on amniote eggs and embryos: An introduction and historical retrospective
Recent research on various aspects of amniote eggs is summarized, including gastrulation, egg shape and eggshell morphology, eggs of Mesozoic dinosaurs, sauropsid yolk sacs, squamate placentation, embryogenesis, and the phylotypic phase of embryonic development.
Unscrambling variation in avian eggshell colour and patterning in a continent-wide study
It is suggested that multiple factors combine to influence egg appearance in this species, and that even in species with highly variable eggs, coloration is not readily explained.
An Early Cretaceous enantiornithine (Aves) preserving an unlaid egg and probable medullary bone
The Cretaceous enantiornithine bird Avimaia schweitzerae is described, which preserves an unlaid egg in the abdominal cavity and putative medullary bone, and is hypothesized to represent the ancestral avian condition.
Avian Coloration Genetics: Recent Advances and Emerging Questions.
This review highlights recent advances and emerging questions associated with the genetic underpinnings of bird color, including breakthroughs related to 2 pigment classes: carotenoids that produce red, yellow, and orange in most birds and psittacofulvins that produce similar colors in parrots.


Dinosaur origin of egg color: oviraptors laid blue-green eggs
The reconstructed blue-green eggs support the origin of previously hypothesized avian paternal care in oviraptorid dinosaurs, and pushes the current limits of the vertebrate molecular and associated soft tissue fossil record, but also provides a perspective on the potential application of this unexplored paleontological resource.
Avian eggshell coloration: new perspectives on adaptive explanations
Evidence from taxa as divergent as sparrowhawks and great tits indicates that protoporphyrin pigments responsible for maculation have a structural function in compensating for eggshell thinning, as caused by calcium stress, and, more recently, dichlorodiphenyltrichloroethane.
The evolution of egg colour and patterning in birds
  • R. Kilner
  • Biology
    Biological reviews of the Cambridge Philosophical Society
  • 2006
A critical review of the literature is presented which, when combined with the results of some comparative analyses, suggests that just a few selective agents can explain much of the variation in egg appearance.
A nesting dinosaur
The specimen described here is the first preserved well enough to determine its precise relationship with the nest, and provides the strongest evidence yet for the presence of avian brooding behaviour in non-avian dinosaurs.
Population Differentiation and Rapid Evolution of Egg Color in Accordance with Solar Radiation
The results suggest that upon relaxation of brood parasitism by an egg mimic, Village Weaver eggs may adapt to solar radiation, and over the past two centuries two introduced populations have evolved more intense blue-green egg colors compared with their source populations.
Why are birds' eggs colourful? Eggshell pigments co‐vary with life‐history and nesting ecology among British breeding non‐passerine birds
The breeding ecology and life history-dependence of eggshell pigment concentrations in these comparative analyses implies that related species share pigment strategies, and that those strategies relate to broad adaptive roles in the evolution of variation in avian eggshell coloration and its underlying mechanisms.
Reproduction in Mesozoic birds and evolution of the modern avian reproductive mode
Significant changes between enantiornithine birds and neornithines include an additional increase in relative egg size and sediment-free incubation, and the latter permitted greater adult–egg contact and likely more efficient incubation.
Detecting pigments from colourful eggshells of extinct birds
Data on pigment detection from eggshells of other extant paleognath birds, together with published information on other modern lineages, confirm tetrapyrroles as ubiquitous and conserved pigments contributing to diverse eggshell colours throughout avian evolution.
Why are birds' eggs speckled?
It was found that pigment spots specifically demarcated thinner areas of shell, with darker spots marking yet thinner shell than paler spots, so accounting for the eggshell's characteristic spot patterns.
A Review of Dromaeosaurid Systematics and Paravian Phylogeny
This study provides the most detailed and comprehensive phylogenetic analysis of paravians to date in order to explore the phylogenetic history of dromaeosaurid taxa and reviews and revises the membership of DromaeOSauridae and provides an apomorphy-based diagnosis for all valid taxa.