Lagenorhynchus obliquidens Gill, 1865

Jo, Yeong-Seok, Baccus, John T. & Koprowski, John L., 2018, Mammals of Korea: a review of their taxonomy, distribution and conservation status, Zootaxa 4522 (1), pp. 1-216 : 148-149

Lagenorhynchus obliquidens Gill, 1865 —Pacific White-sided Dolphin

Lagenorhynchus obliquidens Gill, 1865 p.177 ; Type locality- San Francisco, US; Kuroda, 1938 p.17; Won, 1968 p.222; Kim et al., 2000 p.98; Kim, 2004 p.244.

Range: Most observations of Pacific white-sided dolphins occur during early summer to late autumn over the continental shelf in the East Sea of Korea, especially the central to northern regions ( Sohn et al. 2012; Fig. 100 ).

Remarks: Consistent genetic differences of mtDNA and microsatellite persisted between individuals from the East Sea and offshore North Pacific Ocean. Microsatellite alleles indicated that the Pacific white-sided dolphins in these two areas belong to different populations with severely restricted gene flow. The low genetic diversity and mtDNA genealogy of the populations in the East Sea implied an origin from a small population that colonized the East Sea or experienced population reduction when this sea became isolated from the North Pacific Ocean during a glacial period in the Late Pleistocene ( Hayano et al. 2004). The Pacific white-sided dolphin appears morphologically similar to the dusky dolphin ( Lagenorhynchus obscurus ) in the southern Pacific Ocean. Genetic analysis indicated that the two species diverged about 2 Mya. Both have been traditionally placed in the Genus Lagenorhynchus , but molecular studies showed L. obliquidens was closer to the Genus Cephalorhynchus than L. obscurus . Shirihai and Jarrett (2006) proposed the new Genus Sagmatia s for these species. However, the Pacific white-sided dolphin remains classified as a monotype species.

Figures

FIGURE 100. Range map of Lagenorhynchus obliquidens in Korea.