Date Awarded

2016

Document Type

Dissertation

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Virginia Institute of Marine Science

Advisor

Eric Hilton

Abstract

Thought of as "ancient" fishes, 25 broadly recognized extant sturgeon species are classified in four genera (Acipenser, Huso, Pseudoscaphirhynchus, and Scaphirhynchus). Molecular and morphological analyses have led to broad but conflicting changes to sturgeon phylogeny. For example, the position of Scaphirhynchus among other sturgeons had been contentious, and various sets of sturgeon species have been proposed to make up the subfamily Husinae. Here, a molecular phylogeny of sturgeons, based on the full mitogenome, is presented. In this phylogeny, Scaphirhynchus is recovered with strong support as basal to the other sturgeons. Huso huso is recovered as basal within a clade containing P. kaufmanni and several species of Acipenser, and is proposed as a new, monotypic subfamily Husinae. This phylogeny is used to examine phylogenetic signal in individual genes and in gene families. The protein coding genes as a unit, and individually, along with 16s rRNA, show phylogenetic signal most similar to that of the full mitogenome. The phylogeny, along with evolutionary relationships of pinnipeds and lampreys, provides the basis for the exploration of sturgeon biogeography. Relationships among geographic areas inhabited by sturgeons are found, finding two sets of related areas- a Pacific area group and an Atlantic group. Relationships of areas within and between these groups reflect area relationships proposed by previous biogeographic and geologic studies. Phylogenetic signal is tested amongst ontogenetic characters, and is recovered in the timing at which larval sturgeon teeth are completely resorbed, indicating that the timing of ontogenetic milestones can carry signal. The phylogeny is used to remove confounding signal from, and investigate correlations among, behavioral and morphological ontogenetic characters. Correlation is found between one pair of characters.

DOI

https://dx.doi.org/doi:10.25773/v5-23d7-b702

Rights

© The Author

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