Title page for ETD etd-06102009-100440


Type of Document Master's Thesis
Author Gates, Amber
Author's Email Address amberg@lsu.edu, Amber.Gates@ncmail.net
URN etd-06102009-100440
Title A Systematic Investigation into Relationships within Mexican Pocket Gophers, Thomomys umbrinus (Rodentia: Geomyidae)
Degree Master of Science (M.S.)
Department Biological Sciences
Advisory Committee
Advisor Name Title
Mark S. Hafner Committee Chair
Richard D. Stevens Committee Member
Robb T. Brumfield Committee Member
Keywords
  • Thomomys
  • Taxonomy
  • Mexico
  • Mitochondrial
  • Nuclear
  • Morphological
  • Ecological Niche Modeling
Date of Defense 2009-05-12
Availability unrestricted
Abstract
In the genus Thomomys, external phenotypic differences account for much of the variation among currently named species. Allozyme and mitochondrial studies of the Mexican species, T. umbrinus, have shown strong discordance between genetically defined clades and current species taxonomy. In this study, I analyzed mitochondrial and nuclear DNA sequences, chomosomes, and morphological characters, and used ecological niche modeling to investigate the phylogenetic status of a phenotypically divergent subspecies of T. umbrinus, T. u. atrovarius. Although quantitative morphometrics provided little discrimination among groups within T. umbrinus, the molecular data indicated that there are three allopatric clades. The Pacific coastal clade (T. u. atrovarius) is diagnosable based on multiple characters, including nuclear genotype, habitat preference, and qualitative morphological characters. Accordingly, I resurrect Allenís (1898) species Thomomys atrovarius to represent members of this clade, which occurs in the Pacific coastal region of western Mexico.
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