| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
© 2004 Society of Systematic Biologists
The Evolution of Body Size, Cope's Rule and the Origin of Amniotes
Équipe "Formations squelettiques" FRE CNRS 2696, Case 7077, Université Paris 7 75005 Paris France; E-mail: laurin{at}ccr.jussieu.fr
Edited by Junhyong Kim: Associate Editor
 |
Abstract |
|---|
The evolution of body size in tetrapods is assessed using a database that includes 107 early stegocephalian species ranging in time from the Frasnian (Upper Devonian) to the Tatarian (Upper Permian). All analyses use methods that incorporate phylogenetic information (topology and branch lengths). In all tests, the impact of alternative topologies and branch lengths are assessed. Previous reports that raised doubts about the accuracy of squared-change parsimony assessment of ancestral character value appear to have used datasets in which there was no phylogenetic signal. Hence, squared-change parsimony may be more reliable than suggested in recent studies, at least when a phylogenetic signal is present in the datasets of interest. Analysis using random taxon reshuffling on three reference phylogenies shows that cranial and presacral length include a strong phylogenetic signal. Character optimization of body size in stegocephalians using squared-change parsimony on a time-calibrated phylogeny incorporating branch length information is used to test a previously published scenario on the origin of amniotes and of the amniotic egg that implies that the ancestors of amniotes were small (no more than 10 cm in snout-vent length), and that their size increased subsequent to the appearance of the amniotic egg. The optimization suggests that first amniotes were somewhat larger than previously hypothesized; the estimated snout-vent length is about 24 cm, and the lower end of the 95% confidence interval of the phylogeny that yields the smallest inferred size suggests that no ancestor of amniotes measured less than 12 cm in snout-vent length. Character optimization, permutational multiple linear regressions, and independent contrast analyses show that Cope's rule of phyletic size increase applies to early reptiliomorphs but that it does not apply to early stegocephalians globally.
Keywords: Amniotes; Cope's rule; early tetrapods; Paleozoic; phylogeny
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  F. Jabbour, C. Damerval, and S. Nadot Evolutionary Trends in the Flowers of Asteridae: Is Polyandry an Alternative to Zygomorphy? Ann. Bot., August 1, 2008; 102(2): 153 - 165. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. D. Angielczyk and M. L. Walsh Patterns in the Evolution of Nares Size and Secondary Palate Length in Anomodont Therapsids (Synapsida): Implications for Hypoxia as a Cause of End-Permian Tetrapod Extinctions Journal of Paleontology, May 1, 2008; 82(3): 528 - 542. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Ruta, D. Pisani, G. T Lloyd, and M. J Benton A supertree of Temnospondyli: cladogenetic patterns in the most species-rich group of early tetrapods Proc R Soc B, December 22, 2007; 274(1629): 3087 - 3095. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Marjanovic and M. Laurin Fossils, Molecules, Divergence Times, and the Origin of Lissamphibians Syst Biol, June 1, 2007; 56(3): 369 - 388. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. LAURIN, F. J. MEUNIER, D. GERMAIN, and M. LEMOINE A MICROANATOMICAL AND HISTOLOGICAL STUDY OF THE PAIRED FIN SKELETON OF THE DEVONIAN SARCOPTERYGIAN EUSTHENOPTERON FOORDI Journal of Paleontology, January 1, 2007; 81(1): 143 - 153. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. A. Finarelli and J. J. Flynn Ancestral State Reconstruction of Body Size in the Caniformia (Carnivora, Mammalia): The Effects of Incorporating Data from the Fossil Record Syst Biol, April 1, 2006; 55(2): 301 - 313. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Garland Jr, A. F. Bennett, and E. L. Rezende Phylogenetic approaches in comparative physiology J. Exp. Biol., August 15, 2005; 208(16): 3015 - 3035. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Cubo, F. Ponton, M. Laurin, E. De Margerie, and J. Castanet Phylogenetic Signal in Bone Microstructure of Sauropsids Syst Biol, August 1, 2005; 54(4): 562 - 574. [Abstract] [Full Text] [PDF]
|
|