@techreport{,
title = {Worldwide Phylogeography of the genus Delphinus revisited},
author = {Amaral, A.R.,Beheregaray, L.B.,Sequeira, M.,Robertson, K.M.,Coelho, M.M., Möller, L.M.},
issn = {SC/61/SM11},
year = {2009},
date = {2009-01-01},
journal = {Report to the Scientific Committee of the 61st meeting of the International Whaling Commisssion},
number = {7},
publisher = {International Whaling Commission},
abstract = {The genus Delphinus comprises two species and one subspecies: the short-beaked common
dolphin, Delphinus delphis (Linnaeus, 1758), distributed in continental shelf and pelagic waters of
the Atlantic and Pacific Oceans, the long-beaked common dolphin, D. capensis (Gray, 1828),
distributed in nearshore tropical and temperate waters of the Pacific and Southern Atlantic Oceans,
and the Arabian long-beaked common dolphin, D. capensis tropicalis van Bree, 1971, which
occurs in the Indian Ocean. Here we present a worldwide phylogeographic study based on
sequences of the mitochondrial DNA cytochrome b gene. A total of 279 individuals were
analysed: 211 D. delphis from the Northeast (82) and Northwest (27) Atlantic, and Northeast (28)
and Southwest (74) Pacific; 26 D. capensis from the Northeast Pacific, 18 D. capensis from the
Southeast Atlantic, and 24 D. capensis tropicalis from the Indian Ocean. Haplotype and nucleotide
diversities of most populations were high when compared with other cetacean species, which is
possibly a signature of large, long-term effective population size. Shared haplotypes between the
two common dolphin species and subspecies were found, as well as between all oceans sampled.
Fixation indices (öST and FST) show that the tropicalis and D. capensis samples from the NE
Pacific are differentiated from samples from all other regions. D. delphis from the Northeast and
Southwest Pacific also show some differentiation from samples from other regions, but with
relatively low values of fixation indices. In contrast, the median-joining network reveals clusters
of haplotypes without a clear geographical or taxonomic correspondence. Overall, these results
suggest that relatively high levels of gene flow occur between regions and possibly among
recognized species, questioning current taxonomy, confounding population history and making the
establishment of population boundaries very difficult. Several phylogeographical hypotheses for
the observed patterns are currently being tested with recently developed methods that use
coalescent models for estimating demographic parameters. Additionally, data on a powerful set of
microsatellite markers are being obtained in order to document the direction and magnitude of
events of recent gene flow between populations and oceanic regions.},
keywords = {Arabian Sea, Common dolphin, delphinus capensis, Delphinus delphis, delphinus sp., genetics, Indian Ocean, taxonomy},
pubstate = {published},
tppubtype = {techreport}
}