Scaphirhynchus Conference: Alabama, Pallid, and Shovelnose Sturgeon

St. Louis, Missouri, 11-13 January 2005

2.  MOLECULAR SYSTEMATICS OF THE SHOVELNOSE STURGEONS (SCAPHIRHYNCHINAE) OF NORTH AMERICA AND CENTRAL ASIA

Robert M. Wood, Casey Dillman, Jeffery Ray, Richard L. Mayden, Department of Biology, Saint Louis University, 3507 Laclede Avenue, St. Louis, MO 63103-2010; Phone 314-977-3494; FAX 314-977-3658; wood2@slu.edu, dillmanc@slu.edu, rayjm@slu.edu, maydenrl@slu.edu

Bernard R. Kuhajda*, Department of Biological Sciences, University of Alabama, Box 870345, Tuscaloosa, AL 35487-0345; Phone 205-348-1822; FAX 205-348-6460; bkuhajda@bama.ua.edu

Among the most imperiled sturgeon species worldwide are those in the subgenus Scaphirhynchinae, referred to as shovelnose sturgeons.  These sturgeons are found on two continents; three species within the genus Scaphirhynchus in North America and three species within the genus Pseudoscaphirhynchus in central Asia.  Scaphirhynchus species are found in the Mississippi River Basin (including the Missouri River System) and the Mobile Basin, which have been highly modified for navigation, hydroelectric power, and flood control.  Species of Pseudoscaphirhynchus are endemic to the two main river systems in the Aral Sea Basin, where irrigation has caused the complete dewatering of the lower reaches of the Amu Darya and Syr Darya rivers and the devastation of the Aral Sea ecosystem.  Sympatric species of shovelnose sturgeons are found in thousands of river kilometers within the Mississippi River Basin (S. albus and S. platorynchus) and the Amu Darya System (P. kaufmanni and P. hermanni).  Considerable morphological variation has been documented within each of these species, but none of the intraspecific variants, forms, or clines are clearly defined or currently recognized at a taxonomic level, posing potential problems with any successful recovery or conservation efforts.  Hybridization between sympatric species in both genera is also a concern.  A molecular phylogeny of sturgeon species in these genera, as well as all known morphs of the Eurasian forms has been generated based on mitochondrial DNA sequences.  This phylogeny will be presented and discussed along with the implications of these data for management of these poorly understood taxa.