Integration of the mammalian shoulder girdle within populations and over evolutionary time

K. E. Sears, C. Bianchi, L. Powers, A. L. Beck

Research output: Contribution to journalArticlepeer-review


Morphological integration has the potential to link morphological variation within populations with morphological evolution among species. This study begins to investigate this link by comparing integration among shoulder girdle elements (e.g. scapular blade, glenoid, coracoid, etc.) during the origin and evolution of therian mammals, and within modern bat, opossum and mouse populations. In this study, correlations among skeletal elements and patterns of allometry are used as proxies for integration. Results suggest that shoulder girdle elements tended to vary and evolve independently during the origin of mammals and subsequent radiation of placentals, consistent with the elements' distinct developmental and evolutionary origins. This finding suggests that skeletal element correlations, and therefore integration, can be conserved over large taxonomic and temporal scales. However, marsupials display a different pattern in which shoulder girdle elements tend to be more integrated, with the exception of the coracoid. This finding is consistent with a shift in the pattern of skeletal element integration coincident with the appearance of the marsupial mode of reproduction. This finding provides further evidence that development can play a significant role in the establishment of patterns of skeletal element correlation and that patterns of skeletal element correlation can themselves evolve when faced with sufficient selective pressures.

Original languageEnglish (US)
Pages (from-to)1536-1548
Number of pages13
JournalJournal of Evolutionary Biology
Issue number7
StatePublished - Jul 2013
Externally publishedYes


  • Allometry
  • Coracoid
  • Correlation
  • Mammal-like reptiles
  • Marsupial
  • Morphometrics
  • Placental
  • Scapula

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics


Dive into the research topics of 'Integration of the mammalian shoulder girdle within populations and over evolutionary time'. Together they form a unique fingerprint.

Cite this