Comparative Ontogeny of the Jaws and Feeding Behavior in Five Sturgeons, with a Note on Applications to Phylogenetics

The structure and development of the jaws in sturgeons (Acipenseridae) is distinct from that of other actinopterygians. Larval sturgeons have terminal jaws that shift during ontogeny to a ventrally directed position. They develop and completely resorb dentition early in ontogeny.   They also exhibit dramatic shifts in diet and feeding behavior.  Form and function are inextricably linked, and both change during development. Through examination of closely spaced growth series of hatchery-reared specimens, this study investigates the connections between the timing of changes in jaw morphology and shifts in feeding behavior among five sturgeon species, (Acipenser transmontanus, A. oxyrinchus, A. medirostris, A. fulvescens, and A. brevirostrum).  We draw on published studies of larval feeding behavior in these species to test for correlation between form (developmental osteology) and function (feeding behavioral changes).  Through comparison to a novel phylogeny based on the full mitogenome of sturgeons, we examine phylogenetic signal in the timing of observed ontogenetic changes and discuss the potential utility of these characters for future phylogenetic studies.