Birds have paedomorphic dinosaur skulls

  title={Birds have paedomorphic dinosaur skulls},
  author={Bhart‐Anjan S. Bhullar and Jes{\'u}s Marug{\'a}n-Lob{\'o}n and Fernando Racimo and Gabe S. Bever and Timothy B Rowe and Mark A. Norell and Arhat Abzhanov},
The interplay of evolution and development has been at the heart of evolutionary theory for more than a century. [] Key Method We analysed the variability of a series of landmarks on all known theropod dinosaur skull ontogenies as well as outgroups and birds. The first dimension of variability captured ontogeny, indicating a conserved ontogenetic trajectory. The second dimension accounted for phylogenetic change towards more bird-like dinosaurs. Basally branching eumaniraptorans and avialans clustered with…
Decelerated dinosaur skull evolution with the origin of birds
It is found that the overall skull shape evolved faster in non-avian dinosaurs than in birds across all regions of the cranium, while in birds, the anterior rostrum is the most rapidly evolving skull region, whereas more posterior regions—such as the parietal, squamosal, and quadrate—exhibited high rates in non.
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Ontogenetic, macroevolutionary and morphofunctional patterns in archosaur skulls
  • C. Foth
  • Environmental Science, Geography
  • 2013
The aim of the current thesis is to obtain better and comprehensive insight into skull shape diversity of archosaurs by using a two-dimensional geometric morphometric approach, with a special focus on ontogenetic and macroevolutionary patterns and their relation to function and ecology.
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It is found that theropod skulls primarily differ in relative anteroposterior length and snout depth and to a lesser extent in orbit size and depth of the cheek region, and oviraptorosaurs deviate most strongly from the “typical” and ancestral theropid morphologies.
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The evidence of the actual evolution of the vertebrate brain is analyzed by reviewing morphological data on endocasts and skeletons of several hundred fossil species and comparing these with living
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Darwinopterus exhibits a remarkable ‘modular’ combination of characters: the skull and neck are typically pterodactyloid, exhibiting numerous derived character states, while the remainder of the skeleton is almost completely plesiomorphic and identical to that of basal pterosaurs, supporting the idea that modules were the principal focus of natural selection and played a leading role in evolutionary transitions.
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Results suggest limited support for some pectoral branch lengths being significantly longer only early at/after the origin of flight, and preference for models with partitions defined a priori by anatomical subregion is consistent with a disjunctive pattern of character change for the data set investigated and may have implications for parameterization of Bayesian analyses of morphological data more generally.
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