The Laptev Sea walrus: an enigma revisited
In cooperation with:
Norwegian Polar Institute, Tromsø, Norway
University of Aarhus, National Environmental Research Institute, Department of Wildlife Ecology and Biodiversity, Rønde, Denmark
Greenland Institute of Natural Resources, Nuuk, Greenland
University of Lund, Division of Evolutionary Molecular Systematics, Lund, Sweden
Laboratory of Mammals, Zoological Institute, Russian Academy of Sciences, Saint Petersburg, Russia
The walrus (Odobenus rosmarus) is in some current systematic schemes divided into three subspecies: O. r. rosmarus in the North Atlantic, O. r. divergens in the North Pacific, and O. r. laptevi in the Laptev Sea. These three subspecies have been described as differing in body size, but the taxonomic status of O. r. laptevi is disputed because only few specimens were used for its description and no proper comparative assessment of its phenotypic variation has been conducted. In this study we apply molecular and morphometric methods to assess the taxonomic status of O. r. laptevi and to analyze the systematic and phylogeographic relationships between the purported three walrus subspecies.
Mitochondrial sequence data support the recognition of only two walrus subspecies O. r. rosmarus and O. r. divergens, the latter including individuals from the Laptev Sea. Accordingly, we suggest the subspecies name Odobenus rosmarus laptevi be abandoned and that the Laptev walrus should be recognised as the westernmost population of the Pacific walrus, Odobenus rosmarus divergens.