Functional tests of the competitive exclusion hypothesis for multituberculate extinction

Neil F. Adams*, Emily J. Rayfield, Philip G. Cox, Samuel N. Cobb, Ian J. Corfe

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

7 Citations (Scopus)
161 Downloads (Pure)

Abstract

Multituberculate mammals thrived during the Mesozoic, but their diversity declined from the mid-late Paleocene onwards, becoming extinct in the late Eocene. The radiation of superficially similar, eutherian rodents has been linked to multituberculate extinction through competitive exclusion. However, characteristics providing rodents with a supposed competitive advantage are currently unknown and comparative functional tests between the two groups are lacking. Here, a multifaceted approach to craniomandibular biomechanics was taken to test the hypothesis that superior skull function made rodents more effective competitors. Digital models of the skulls of four extant rodents and the Upper Cretaceous multituberculate Kryptobaatar were constructed and used (i) in finite-element analysis to study feeding-induced stresses, (ii) to calculate metrics of bite force production and (iii) to determine mechanical resistances to bending and torsional forces. Rodents exhibit higher craniomandibular stresses and lower resistances to bending and torsion than the multituberculate, apparently refuting the competitive exclusion hypothesis. However, rodents optimize bite force production at the expense of higher skull stress and we argue that this is likely to have been more functionally and selectively important. Our results therefore provide the first functional lines of evidence for potential reasons behind the decline of multituberculates in the changing environments of the Paleogene.

Original languageEnglish
Article number181536
Pages (from-to)181536
JournalRoyal Society Open Science
Volume6
Issue number3
DOIs
Publication statusPublished - 6 Mar 2019

Keywords

  • Digital reconstruction
  • Finite-element analysis
  • Macroevolution
  • Mammalian evolution
  • Multituberculata
  • Rodentia

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