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Body size distribution of the dinosaurs.

O'Gorman EJ, Hone DW - PLoS ONE (2012)

Bottom Line: Here, we address this question by comparing the distribution of maximum species body size for dinosaurs to an extensive set of extant and extinct vertebrate groups.We also examine the body size distribution of dinosaurs by various sub-groups, time periods and formations.We find that dinosaurs exhibit a strong skew towards larger species, in direct contrast to modern day vertebrates.

View Article: PubMed Central - PubMed

Affiliation: School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom.

ABSTRACT
The distribution of species body size is critically important for determining resource use within a group or clade. It is widely known that non-avian dinosaurs were the largest creatures to roam the Earth. There is, however, little understanding of how maximum species body size was distributed among the dinosaurs. Do they share a similar distribution to modern day vertebrate groups in spite of their large size, or did they exhibit fundamentally different distributions due to unique evolutionary pressures and adaptations? Here, we address this question by comparing the distribution of maximum species body size for dinosaurs to an extensive set of extant and extinct vertebrate groups. We also examine the body size distribution of dinosaurs by various sub-groups, time periods and formations. We find that dinosaurs exhibit a strong skew towards larger species, in direct contrast to modern day vertebrates. This pattern is not solely an artefact of bias in the fossil record, as demonstrated by contrasting distributions in two major extinct groups and supports the hypothesis that dinosaurs exhibited a fundamentally different life history strategy to other terrestrial vertebrates. A disparity in the size distribution of the herbivorous Ornithischia and Sauropodomorpha and the largely carnivorous Theropoda suggests that this pattern may have been a product of a divergence in evolutionary strategies: herbivorous dinosaurs rapidly evolved large size to escape predation by carnivores and maximise digestive efficiency; carnivores had sufficient resources among juvenile dinosaurs and non-dinosaurian prey to achieve optimal success at smaller body size.

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Frequency distribution of dinosaur species body size for two major formations: (a) the Morrison and (b) Dinosaur Park.Both formations showed negatively-skewed distributions, with the Morrison formation approximately unimodal and the Dinosaur Park formation best fitted by a bimodal distribution (see Table 2). These patterns should be interpreted with caution, however, due to the small number of data points for each formation.
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pone-0051925-g006: Frequency distribution of dinosaur species body size for two major formations: (a) the Morrison and (b) Dinosaur Park.Both formations showed negatively-skewed distributions, with the Morrison formation approximately unimodal and the Dinosaur Park formation best fitted by a bimodal distribution (see Table 2). These patterns should be interpreted with caution, however, due to the small number of data points for each formation.

Mentions: Reptile data were collated from a number of sources. Snout-vent lengths (SVL) for 4,874 lizard species were taken from Shai Meiri’s dataset [35]. Here, maximum SVL is seen as a good measure of the size potential in a population and is tightly correlated with mean adult SVL and SVL at sexual maturity [35], [36]. Lizard body masses were obtained using the SVL-mass allometries listed in Table 2 of Meiri’s 2010 publication [37]. Body mass data for a further 1,330 reptile species were obtained from Guyer and Boback’s online published dataset [38]. This included 1,030 snake species, 260 turtle species, 22 crocodilian species and a further 18 lizard species. Snakes were measured as maximum total length (TL) and converted to body mass using the TL-mass allometry listed in Pough’s 1980 publication [39]. Turtles were measured as maximum carapace length (CL) and converted to body mass using the CL-mass allometry listed in Pough’s 1980 publication [39]. Crocodiles were measured as maximum TL and converted to body mass using the TL-mass allometry listed in Table 3 of Farlow et al.’s 2005 publication [40]. Body masses for the two existing species of tuatara were taken from two recent publications [41], [42]. This resulted in body mass estimates for a total of 6,206 out of approximately 8,700 reptile species (71% completeness).


Body size distribution of the dinosaurs.

O'Gorman EJ, Hone DW - PLoS ONE (2012)

Frequency distribution of dinosaur species body size for two major formations: (a) the Morrison and (b) Dinosaur Park.Both formations showed negatively-skewed distributions, with the Morrison formation approximately unimodal and the Dinosaur Park formation best fitted by a bimodal distribution (see Table 2). These patterns should be interpreted with caution, however, due to the small number of data points for each formation.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3526529&req=5

pone-0051925-g006: Frequency distribution of dinosaur species body size for two major formations: (a) the Morrison and (b) Dinosaur Park.Both formations showed negatively-skewed distributions, with the Morrison formation approximately unimodal and the Dinosaur Park formation best fitted by a bimodal distribution (see Table 2). These patterns should be interpreted with caution, however, due to the small number of data points for each formation.
Mentions: Reptile data were collated from a number of sources. Snout-vent lengths (SVL) for 4,874 lizard species were taken from Shai Meiri’s dataset [35]. Here, maximum SVL is seen as a good measure of the size potential in a population and is tightly correlated with mean adult SVL and SVL at sexual maturity [35], [36]. Lizard body masses were obtained using the SVL-mass allometries listed in Table 2 of Meiri’s 2010 publication [37]. Body mass data for a further 1,330 reptile species were obtained from Guyer and Boback’s online published dataset [38]. This included 1,030 snake species, 260 turtle species, 22 crocodilian species and a further 18 lizard species. Snakes were measured as maximum total length (TL) and converted to body mass using the TL-mass allometry listed in Pough’s 1980 publication [39]. Turtles were measured as maximum carapace length (CL) and converted to body mass using the CL-mass allometry listed in Pough’s 1980 publication [39]. Crocodiles were measured as maximum TL and converted to body mass using the TL-mass allometry listed in Table 3 of Farlow et al.’s 2005 publication [40]. Body masses for the two existing species of tuatara were taken from two recent publications [41], [42]. This resulted in body mass estimates for a total of 6,206 out of approximately 8,700 reptile species (71% completeness).

Bottom Line: Here, we address this question by comparing the distribution of maximum species body size for dinosaurs to an extensive set of extant and extinct vertebrate groups.We also examine the body size distribution of dinosaurs by various sub-groups, time periods and formations.We find that dinosaurs exhibit a strong skew towards larger species, in direct contrast to modern day vertebrates.

View Article: PubMed Central - PubMed

Affiliation: School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom.

ABSTRACT
The distribution of species body size is critically important for determining resource use within a group or clade. It is widely known that non-avian dinosaurs were the largest creatures to roam the Earth. There is, however, little understanding of how maximum species body size was distributed among the dinosaurs. Do they share a similar distribution to modern day vertebrate groups in spite of their large size, or did they exhibit fundamentally different distributions due to unique evolutionary pressures and adaptations? Here, we address this question by comparing the distribution of maximum species body size for dinosaurs to an extensive set of extant and extinct vertebrate groups. We also examine the body size distribution of dinosaurs by various sub-groups, time periods and formations. We find that dinosaurs exhibit a strong skew towards larger species, in direct contrast to modern day vertebrates. This pattern is not solely an artefact of bias in the fossil record, as demonstrated by contrasting distributions in two major extinct groups and supports the hypothesis that dinosaurs exhibited a fundamentally different life history strategy to other terrestrial vertebrates. A disparity in the size distribution of the herbivorous Ornithischia and Sauropodomorpha and the largely carnivorous Theropoda suggests that this pattern may have been a product of a divergence in evolutionary strategies: herbivorous dinosaurs rapidly evolved large size to escape predation by carnivores and maximise digestive efficiency; carnivores had sufficient resources among juvenile dinosaurs and non-dinosaurian prey to achieve optimal success at smaller body size.

Show MeSH
Related in: MedlinePlus