Type of Document Dissertation Author Holliday, Jill Alexandra Author's Email Address email@example.com URN etd-04092007-191252 Title Phylogeny and character change in the Feloid Carnivora. Degree Doctor of Philosophy Department Biological Science, Department of Advisory Committee
Advisor Name Title David Swofford Committee Member Gerg Erickson Committee Member Joseph Travis Committee Member Scott Steppan Committee Member William Parker Committee Member Keywords
- Character Evolution
Date of Defense 2007-03-21 Availability unrestricted AbstractABSTRACT
This study presents the results of dissertation research performed by Jill Holliday, and includes a study of the effects of specialization to a dental/dietary morphotype, that of the hypercarnivore, on subsequent morphological and taxonomic diversification. This work demonstrates that morphological specialization to hypercarnivory does limit subsequent morphological diversity (disparity) and also reduces frequency of morphological change over the course of a lineage, but has no effect on subsequent taxonomic diversity. Additionally a test of the possibility of biased morphological character evolution as taxa evolve a more hypercarnivorous phenotype indicates that specialists are not subject to strong directional selection, but are instead unable to reverse to a more generalized condition or even move into alternative open niche space, which strongly implies the effects of a functional constraint.
To provide a more robust and detailed phylogeny than is currently available, a molecular and morphological dataset was compiled for the feloid Carnivora, a group in which hypercarnivory has evolved at least three times. The molecular dataset is composed of three nuclear and one mitochondrial gene and represents over 5000 base pairs of data for 39 ingroup taxa. This dataset was analyzed under maximum likelihood and Bayesian models, and represents the most robust, thoroughly sampled phylogeny yet available for the feloid Carnivora. However, since the focus of this research is to evaluate character evolution, 103 morphological characters were added to the dataset so that fossil material, particularly ancestral feloids, could also be placed in a phylogenetic context. This combined evidence phylogeny was analyzed using Bayesian inference and with parsimony using a backbone constraint tree based on the previously obtained molecular phylogeny.
Both the molecular-only and the combined evidence phylogenies significantly clarify relationships among the feloid families, and also establish the early pattern of divergences within this group. This study establishes that the monotypic family Nandiinidae is the sister to all other extant feloids, while the family Viverridae is the sister to a clade comprised of (Felidae)((Hyaenidae)(Herpestidae/Eupleridae))). The combined evidence tree also allows placement of a number of feloid fossils that occupy key positions at the base of the radiation of extant families. Thus, the genus Herpestides is an early member of Hyaenidae(Herpestidae/Eupleridae), while Plioviverrops is an early herpestid. Finally, the primitive feloids Stenoplesictis, Paleoprionodon, and Haplogale do not position within any of any of the extant families, and instead comprise a paraphyletic grouping at the base of the feloid tree.
With these results, the combined evidence phylogeny will enable a more accurate designation of character polarities and estimation of ancestral conditions, which will in turn facilitate additional research in these groups. These phylogenies are the best supported, most thoroughly sampled trees yet produced for the feloid Carnivora, and represent a significant contribution to feloid phylogenetics.
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