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Additional Information

More information is available at carthage.edu/celebration-scholars/. The following are members of the Research, Scholarship, and Creativity Committee who are eager to listen to ideas and answer questions:

  • Thomas Carr
  • Katherin Hilson
  • Kim Instenes
  • John Kirk
  • Sarah Terrill

A Cladistic Ontogeny of Quaternary Proboscideans and Ancestral Patterns of Mammalian Epiphyseal Fusion

Name: Adam Larson
Major: Biology
Hometown: Kenosha, WI
Faculty Sponsor: Thomas Carr
Other Sponsors:  
Type of research: Senior thesis
Funding: Funds from Carthage to present at the 79th Annual Meeting of the Society of Vertebrate Paleontology in Brisbane, Australia

Abstract

Proboscidean ontogeny has been previously studied, but typically only a single type of growth character at a time is studied, or methods unable to recover a high-resolution growth series are used. This study seeks to identify ontogenetic growth series for three living proboscidean taxa (Loxodonta africanaL. cyclotis, and Elephas maximus) and five extinct proboscidean taxa (Mammuthus primigeniusM. columbiM. trogontheriiPalaeoloxodon antiquus, and Mammut americanum) through a quantitative cladistic analysis and test results with previous research on ontogeny, sexual dimorphism, and phylogeny. Fourteen growth series were recovered, eight for species as a whole and six sex-based growth series that only include specimens of a single sex. The growth series generally align with previous estimations of age, are congruent with previous work on epiphyseal fusion, and show evidence for sexual dimorphism in L. africana. Growth series were combined with previous research using shared congruent sequences and inferences on the timing of growth characters not found in both this study to improve resolution, and were combined with each other to recover the growth series of the common ancestor of Elephantidae with fifteen stages and eighteen characters. The growth series of the common ancestor of Elephantidae was compared with published data on epiphyseal fusion in Mammalia. Growth character sequences were identified as synapomorphies of Mammalia, Theria, Eutheria, Metatheria, Atlantogenata, Primates, Rodentia, Paenungulata, Hyracoidea, and Elephantidae.

Submit date: March 20, 2020, 10:32 p.m.

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