Sturgeon (Acipenseridae) Phylogeny, Biogeography, & Ontogeny
Thought o f 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 o f Scaphirhynchus among other sturgeons had been contentious, and various sets o f sturgeon species have been proposed to make up the subfamily Husinae. Here, a molecular phylogeny o f sturgeons,
... 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 w ith 16s rRNA, show phylogenetic signal most similar to that of the full mitogenome. The phylogeny, along w ith evolutionary relationships of pinnipeds and lampreys, provides the basis fo r the exploration of sturgeon biogeography. Relationships among geographic areas inhabited by sturgeons are found, finding tw o sets o f related areas-a Pacific area group and an Atlantic group. Relationships o f 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 tim ing at which larval sturgeon teeth are completely resorbed, indicating that the timing o f 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 o f characters.