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Open Access item Natural or Naturalized? Phylogeography Suggests That the Abundant Sea Urchin Arbacia lixula Is a Recent Colonizer of the Mediterranean.
|Authors:||Wangensteen, Owen S.|
|Publisher:||Public Library of Science|
|Citation:||Plos One 7(9) : e45067 (2012)|
|Abstract:||We present the global phylogeography of the black sea urchin Arbacia lixula, an amphi-Atlantic echinoid with potential to
strongly impact shallow rocky ecosystems. Sequences of the mitochondrial cytochrome c oxidase gene of 604 specimens
from 24 localities were obtained, covering most of the distribution area of the species, including the Mediterranean and
both shores of the Atlantic. Genetic diversity measures, phylogeographic patterns, demographic parameters and population
differentiation were analysed. We found high haplotype diversity but relatively low nucleotide diversity, with 176
haplotypes grouped within three haplogroups: one is shared between Eastern Atlantic (including Mediterranean) and
Brazilian populations, the second is found in Eastern Atlantic and the Mediterranean and the third is exclusively from Brazil.
Significant genetic differentiation was found between Brazilian, Eastern Atlantic and Mediterranean regions, but no
differentiation was found among Mediterranean sub-basins or among Eastern Atlantic sub-regions. The star-shaped
topology of the haplotype network and the unimodal mismatch distributions of Mediterranean and Eastern Atlantic
samples suggest that these populations have suffered very recent demographic expansions. These expansions could be
dated 94–205 kya in the Mediterranean, and 31–67 kya in the Eastern Atlantic. In contrast, Brazilian populations did not
show any signature of population expansion. Our results indicate that all populations of A. lixula constitute a single species.
The Brazilian populations probably diverged from an Eastern Atlantic stock. The present-day genetic structure of the species
in Eastern Atlantic and the Mediterranean is shaped by very recent demographic processes. Our results support the view
(backed by the lack of fossil record) that A. lixula is a recent thermophilous colonizer which spread throughout the
Mediterranean during a warm period of the Pleistocene, probably during the last interglacial. Implications for the possible
future impact of A. lixula on shallow Mediterranean ecosystems in the context of global warming trends must be
|Description:||16 páginas, 9 tablas, 6 figuras.|
|Publisher version (URL):||http://dx.doi.org/e45067. doi:10.1371/journal.pone.0045067|
|Appears in Collections:||(CEAB) Artículos|
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