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Body Size Evolution in Extant Oryzomyini Rodents: Cope's Rule or Miniaturization?

By Jorge Avaria-Llautureo, Cristián E. Hernández, Dusan Boric-Bargetto, Cristian B. Canales-Aguirre, Bryan Morales-Pallero and Enrique Rodríguez-Serrano


At the macroevolutionary level, one of the first and most important hypotheses that proposes an evolutionary tendency in the evolution of body sizes is “Cope's rule". This rule has considerable empirical support in the fossil record and predicts that the size of species within a lineage increases over evolutionary time. Nevertheless, there is also a large amount of evidence indicating the opposite pattern of miniaturization over evolutionary time. A recent analysis using a single phylogenetic tree approach and a Bayesian based model of evolution found no evidence for Cope's rule in extant mammal species. Here we utilize a likelihood-based phylogenetic method, to test the evolutionary trend in body size, which considers phylogenetic uncertainty, to discern between Cope's rule and miniaturization, using extant Oryzomyini rodents as a study model. We evaluated body size trends using two principal predictions: (a) phylogenetically related species are more similar in their body size, than expected by chance; (b) body size increased (Cope's rule)/decreased (miniaturization) over time. Consequently the distribution of forces and/or constraints that affect the tendency are homogenous and generate this directional process from a small/large sized ancestor. Results showed that body size in the Oryzomyini tribe evolved according to phylogenetic relationships, with a positive trend, from a small sized ancestor. Our results support that the high diversity and specialization currently observed in the Oryzomyini tribe is a consequence of the evolutionary trend of increased body size, following and supporting Cope's rule

Topics: Research Article
Publisher: Public Library of Science
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Provided by: PubMed Central

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  1. (1887) The origin of the fittest.
  2. (2011). A bayesian framework to estimate diversification rates and their variation through time and space.
  3. (2011). A new genus and species of rodent from the Brazilian Atlantic Forest (Rodentia: Cricetidae: Sigmodontinae: Oryzomyini), with comments on oryzomyine biogeography.
  4. (2008). A new genus of Oryzomyini rodent (Cricetidae: Sigmodontinae) from the Pleistocene of Argentina.
  5. (1996). A new species Holochilus (Rodentia: Sigmodontinae) from the middle Pleistocene of Bolivia and its phylogenetic significance.
  6. (2001). A new species of extinct oryzomyine rodent from the Quaternary of Curac ¸ao, Netherlands Antilles.
  7. (2000). Accommodating phylogenetic uncertainty in evolutionary studies.
  8. (2002). Accounting for phylogenetic uncertainty in comparative studies of evolution and adaptation.
  9. (2004). Acosta A
  10. (1973). An explanation for Cope’s rule.
  11. (2003). An index of substitution saturation and its application.
  12. (1988). Are the smallest organisms the most diverse?
  13. (2009). Assessing substitution saturation with DAMBE. In: LemeyP,SalemiM,VandammeAM,eds.Thephylogenetichandbook:Apractical approach to DNA and protein phylogeny. Cambridge:
  14. (2011). Available: Accessed
  15. (1995). Bayesian data analysis. London: Chapman and Hall.
  16. (2001). Bayesian inference of phylogeny and its impact on evolutionary biology.
  17. (1986). Body size, ecological dominance and Cope’s rule.
  18. (1997). Closing of the Central American seaway and Neogene coastal upwelling along the Pacific coast of South America.
  19. (1994). CLUSTAL W: improving the sensitivity of progressive sequence alignment through sequence weighting, position-specific gap penalties and weight matrix choice.
  20. (2000). Comments on recent advances in understanding sigmodontine phylogeny and evolution.
  21. (2003). Comparaciones interespecı ´ficas y me ´todos estadı ´sticos filogene ´ticos. In: Bozinovic F, ed. Fisiologı ´a ecolo ´gica y evolutiva. Teorı ´a y casos de estudio en animales. Santiago, Chile: Ediciones Universidad Cato ´lica de Chile.
  22. (1998). Cope’s rule and the dynamics of body mass evolution in North American fossil mammals.
  23. (2006). Cope’s rule in cryptodiran turtles: do they body sizes of extant species reflect a trend of phyletic size increase?
  24. (2007). Cope’s rule in the Pterosauria, and differing perceptions of Cope’s rule at different taxonomic levels.
  25. (1993). Cope’s rule, the island rule and the scaling of mammalian population density.
  26. (2008). Core Team
  27. D’Elı ´a G, Ortı ´z PE (2002) Sigmodontinos fo ´siles (Rodentia, Muroidea, Sigmodontinae) de Ame ´rica del Sur: estado actual de su conocimiento y prospectiva.
  28. (2001). DAMBE: data analysis in molecular biology and evolution.
  29. (2000). Data analysis in molecular biology and evolution.
  30. den Hoek Ostende LW (2010) New genus and two new species of Pleistocene oryzomyines (Cricetidae: Sigmodontinae) from Bonaire, Netherlands Antilles.
  31. (2006). Detecting the node-density artifact in phylogeny reconstruction.
  32. (2000). Directionality theory and the evolution of body size.
  33. (2011). Ecological specialization in fossil mammals explain Cope’s rule.
  34. (2007). Effects of body size and lifestyle on evolution of mammal life histories.
  35. (2001). Empirical and hierarchical Bayesian estimation of ancestral states.
  36. (1998). Estimating mean body masses of marine mammals from maximum body lengths.
  37. (1995). Evolution of body size: varanid lizards as a model system.
  38. (2007). Evolution of miniaturization and the phylogenetic position of Paedocypris, comprising the world’s smallest vertebrate.
  39. (2010). Extinction rates should not be estimated from molecular phylogenies.
  40. (1992). Fossil Horses: Systematics, Palaeobiology and Evolution of the Family Equidae. New York:
  41. (2000). Independent contrasts succeed where ancestor reconstruction fails in a known bacteriophage phylogeny.
  42. (2004). Individual-level selection as a cause of Cope’s rule of phyletic size increase.
  43. (1997). Inferring evolutionary processes from phylogenies.
  44. (2004). Inferring Phylogenies.
  45. (1999). Inferring the historical patterns of biological evolution.
  46. (2001). Law of the unspecialized: broken?.
  47. (1992). Life history and morphological evolution.
  48. (2010). Little evidence for Cope’s rule from Bayesian phylogenetic analysis of extant mammals.
  49. (1995). Macroecology.
  50. (2001). Major fungal lineages derived from lichensymbiotic ancestors.
  51. (2011). Mammalian phylogeny reveals recent diversification rate shifts.
  52. (1999). Markov Chain Monte Carlo algorithms for the Bayesian analysis of phylogenetic trees.
  53. (2000). Matters of the record.
  54. (2006). Meade A
  55. Meade A (2005) Bayesian estimation of correlated evolution across cultures: A case study of marriage systems and wealth transfer at marriage.
  56. Meade A (2005) Mixture models in phylogenetic inference.
  57. (1994). Mechanisms of large-scale evolutionary trends.
  58. (2003). Micromamı ´feros (Didelphimorphia y Rodentia) de norpatagonia extra andina, Argentina: taxonomı ´a alfa y biogeografı ´a.
  59. (1993). Miniaturization of body size: organismal consequences and evolutionary significance.
  60. (2002). Modelling the evolution of continuously varying characters on phylogenetic trees.
  61. (1998). Molecular systematic and paleobiogeography of the South American sigmodontine rodents.
  62. (2011). Multiple routes of mammalian diversification.
  63. (2000). New methods for quantifying macroevolutionary patterns and processes.
  64. (2006). On the Sigmodontinae radiation (Rodentia, Cricetidae): An appraisal of the phylogenetic position of Rhagomys.
  65. (2009). On the taxonomic status of Oryzomys curasoae McFarlane and Debrot,
  66. (2002). Phylogenetic analysis and comparative data: A test and review of evidence.
  67. (1999). Phylogenetic relationships and the radiation of sigmodontine rodents in South America: Evidence from Cytochrome b.
  68. (2006). Phylogenetic relationships of oryzomyine rodents (Muroidea: Sigmodontinae): separate and combined analyses of morphological and molecular data.
  69. (2010). Phylogenetic relationships of the pygmy rice rats of the genus Oligoryzomys Bangs,
  70. (2003). Phylogenetics of Sigmodontinae (Rodentia, Muroidea, Cricetidae), with special reference to the akodont group, and with additional comments on historical biogeography.
  71. (1997). Phylogenies and the comparative method: general approach to incorporating phylogenetic information into the analysis of interspecific data.
  72. (2004). Phylogeny and divergence-date estimates of rapid radiations in Muroid rodents based on multiple nuclear genes.
  73. (2003). Phylogeny estimation: traditional and Bayesian approaches.
  74. (2004). Phylogeny of Muroid rodents: relationships within and among major lineages as determined by IRBP gene sequences.
  75. (2003). Phylogeny of Neotropical oryzomyine rodents (Muridae: Sigmodontinae) based on the nuclear IRBP exon.
  76. (2011). Punctuational Evolution and the Node-Density Artifact website. Available: Accessed
  77. (2001). Purvis A
  78. (2001). Quantifying passive and driven large-scale evolutionary trends.
  79. (2010). Quantitative traits and diversification.
  80. (2007). Rambuat A
  81. (2008). Scale-dependence of Cope’s rule in body size evolution of Paleozoic brachiopods.
  82. (1984). Scaling, why is animal size so important?. New York:
  83. (1996). Sigmodontinos (Mammalia, Rodentia) pleistoce ´nicos del sudoeste de la provincia de Buenos Aires (Argentina): aspectos sistema ´ticos, paleozoogeogra ´ficos y paleoambientales.
  84. (2010). Taxonomy, phylogeny and diversity of the extinct Lesser Antillean rice rats (Sigmodontinae: Oryzomyini), with description of a new genus and species.
  85. (2006). Ten new genera of Oryzomyine rodents (Cricetidae:Sigmodontinae). Am Mus Novit 3537:
  86. (2009). Testing the impact of miniaturization on phylogeny: Paleozoic dissorophoid amphibians.
  87. (2001). The animal species-body size distribution of Marion Island.
  88. (2002). The distribution of species range size: a stochastic process.
  89. (1983). The ecological implications of body size.
  90. (2002). The effect of miniaturized body size on skeletal morphology in frogs.
  91. (2008). The evolution and distribution of species body size.
  92. (1998). The evolution of body size in birds. I. Evidence for nonrandom diversification.
  93. (2003). The evolution of body size in extant groups of North American freshwater fishes: speciation, size distributions, and Cope’s rule.
  94. (2010). The evolution of maximum body size of terrestrial mammals.
  95. (1999). The maximum likelihood approach to reconstructing ancestral character states of discrete characters on phylogenies.
  96. (1988). Trends as changes in variance: a new slant on progress and directionality in evolution.
  97. (1995). Uncertainty in ancient phylogenies.
  98. (2000). Understanding the dynamics of trends within evolving lineages.

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