Towards a phylogenetic taxonomy of sturgeons (Acipenseriformes: Acipenseridae)

Acipenseriformes, comprising sturgeons and paddlefishes, is one of the three ancient and species-poor living lineages of non-teleost Actinopterygii. Here, we use DNA sequence and morphological data to investigate the phylogenetic relationships of sturgeons and produce a phylogenetic basis for the taxonomy of Acipenseridae. We resolve five major clades within sturgeons. As in previous studies, species of Scaphirhynchus and Pseudoscaphirhynchus each resolve as monophyletic groups, whereas Huso and Acipenser are paraphyletic. To render all acipenserid genera monophyletic, we confine Acipenser to A. sturio Linnaeus 1758, A. oxyrincus Mitchill 1815, and A. desotoi Vladykov 1955, and resurrect the genus name Sinosturio Jaekel 1929 for a well-supported clade consisting of Sinosturio dabryanus (Duméril 1869), S. sinensis (Gray 1835), S. transmontanus (Richardson 1836), S. schrenckii (Brandt 1869), S. medirostris (Ayres 1854), S. mikadoi (Hilgendorf 1892), and S. dauricus (Georgi 1775). Phylogenies that we infer using concatenated nuclear genes and concatenated nuclear and mitochondrial DNA sequences resolve Huso huso (Linnaeus 1758) and ten species traditionally classified as Acipenser as a monophyletic group. We suggest applying the genus name Huso to this lineage. Our analyses provide a robust framework for a phylogenetic taxonomy of sturgeons and a foundation for future studies of the relationships and ages of acipenserid clades. Keywords: PhyloCode; Acipenseriformes; Acipenseridae; sturgeon; taxonomy; systematics; phylogenetics