Dinosaurian growth rates and bird origins

  title={Dinosaurian growth rates and bird origins},
  author={Kevin Padian and Armand J. de Ricql{\`e}s and John R. Horner},
Dinosaurs, like other tetrapods, grew more quickly just after hatching than later in life. However, they did not grow like most other non-avian reptiles, which grow slowly and gradually through life. Rather, microscopic analyses of the long-bone tissues show that dinosaurs grew to their adult size relatively quickly, much as large birds and mammals do today. The first birds reduced their adult body size by shortening the phase of rapid growth common to their larger theropod dinosaur relatives… 

Developmental Plasticity in the Life History of a Prosauropod Dinosaur

Long-bone histology indicates that the most common early dinosaur, the prosauropod Plateosaurus engelhardti from the Upper Triassic of Central Europe, had variable life histories, and was influenced by environmental factors, as in modern ectothermic reptiles, but not in mammals, birds, or other dinosaurs.

The interpretation of dinosaur growth patterns.

Assessing dinosaur growth patterns: a microscopic revolution.

  • G. Erickson
  • Geography, Environmental Science
    Trends in ecology & evolution
  • 2005

Sexual maturity in growing dinosaurs does not fit reptilian growth models

It is shown by counting lines of arrested growth and performing growth curve reconstructions that Tenontosaurus, Allosaurus, and Tyrannosaurus were reproductively mature by 8, 10, and 18 years, respectively, which suggests that these dinosaurs were born relatively precocial and experienced high adult mortality.

On Dinosaur Growth

From the recent development of means to study tissue-level growth, age these animals, and make growth curves, it is now understood that dinosaurs grew both disruptively and determinately, and that basal birds retained dinosaurian physiology.


The evolution of life history strategies in dinosaurs and pterosaurs, as they relate to rates of growth and adult body sizes, will be better understood as more complete histological studies place these data into phylogenetic and ontogenetic contexts.

Anomalously high variation in postnatal development is ancestral for dinosaurs but lost in birds

It is shown that deep within Dinosauria, among the earliest-diverging dinosaurs, anomalously high intraspecific variation is widespread but then is lost in more derived theropods, which is ancestral for dinosaurs and their closest relatives.

Evidence for mesothermy in dinosaurs

Analysis of animal growth energetics indicates that dinosaurs had intermediate metabolic rates and elevated but labile temperatures, suggesting that the modern dichotomy of endothermic versus ectothermic is overly simplistic.

The evolution of intraspecific variation, growth, and body size in early theropod dinosaurs

The authors' analyses suggest intraspecific variation in growth is high in early dinosaurs but largely absent in birds, and non-metric multidimensional scaling analysis suggests this variation is not related to sexual differences.

Modeling growth rates for sauropod dinosaurs

Alternative method of estimating limb length and body mass for each growth line, and fitting the resulting age/ mass data to the von Bertalanffy growth equation, yields a revised growth curve suggesting that sauropods grew at rates similar to other dinosaurs in spite of their great size.



Speculations on the growth rate and reproduction of some dinosaurs

  • T. Case
  • Environmental Science, Geography
  • 1978
If the dinosaurs Protoceratops grangeri and Hypselosaurus sp. grew at rates predicted for their body size from extant reptiles, their expected ages at reproductive maturity would be about 20 and 62

Dinosaurian growth patterns and rapid avian growth rates

It is shown that dinosaurs exhibited sigmoidal growth curves similar to those of other vertebrates, but had unique growth rates with respect to body mass.

Mesozoic avian bone microstructure: physiological implications

The bone microstructure of the Late Cretaceous birds Patagopteryx deferrariisi and members of the Enantiornithes is reported, suggesting that birds developed classic endothermy relatively late in their phylogenetic history.

The smallest known non-avian theropod dinosaur

This is the first mature non-avian dinosaur to be found that is smaller than Archaeopteryx, and it eliminates the size disparity between the earliest birds and their closest non-Avian theropod relatives.

Two feathered dinosaurs from northeastern China

Two theropods from the Upper Jurassic/Lower Cretaceous Chaomidianzi Formation of Liaoning province, China are described, which represent stages in the evolution of birds from feathered, ground-living, bipedal dinosaurs.

Growth curve of Psittacosaurus mongoliensis Osborn (Ceratopsia: Psittacosauridae) inferred from long bone histology

The first reconstruction of a growth curve (mass vs. age) for a dinosaur was made for this taxon using a new method called Developmental Mass Extrapolation, and the results suggest P. mongoliensis had an S-shaped growth curve characteristics of most extant vertebrates, and had maximal growth rates that exceeded extant reptiles and marsupials, but were slower than most avian and eutherian taxa.

Allometric Scaling in the Earliest Archaeopteryx lithographica

Allometric patterns suggest that Archaeopteryx was likely a homeothermic endotherm with rapid growth and precocial abilities for running and flying, as compared to growth gradients of other dinosaurs, extant ectotherms, and extant endotherms.

How the ‘terror crocodile’ grew so big

Deinosuchus is a giant crocodylian from the Late Cretaceous period of North America. It was 8 to 10 metres long and weighed between 2,500 and 5,000 kg, three to five times more than the largest

Avian growth and development : evolution within the altricial-precocial spectrum

The data set of Avian Growth Parameters Summary, Conclusions, and Research Agenda shows that the evolution of Developmental Mode in Birds is driven by a combination of Variation, Constraint, and Phylogeny.

Ontogenetic histology of Apatosaurus (Dinosauria: Sauropoda): New insights on growth rates and longevity

All Apatosaurus bones sampled corroborate the hypothesis of sustained rapid growth rates for most of ontogeny, followed by gradual decline with attainment of maximum size, as well as regular variation in speeds of osteogenesis.