Open AccessWider sampling reveals a non‐sister relationship for geographically contiguous lineages of a marine mussel
Author(s) -
Cunha Regina L.,
Nicastro Katy R.,
Costa Joana,
McQuaid Christopher D.,
Serrão Ester A.,
Zardi Gerardo I.
Publication year - 2014
Publication title -
ecology and evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.17
H-Index - 63
ISSN - 2045-7758
DOI - 10.1002/ece3.1033
Subject(s) - phylogeography , vicariance , lineage (genetic) , biological dispersal , biology , sister group , phylogenetic tree , evolutionary biology , ecology , clade , population , demography , biochemistry , sociology , gene
The accuracy of phylogenetic inference can be significantly improved by the addition of more taxa and by increasing the spatial coverage of sampling. In previous studies, the brown mussel P erna perna showed a sister–lineage relationship between eastern and western individuals contiguously distributed along the S outh A frican coastline. We used mitochondrial ( COI ) and nuclear ( ITS ) sequence data to further analyze phylogeographic patterns within P . perna . Significant expansion of the geographical coverage revealed an unexpected pattern. The western S outh A frican lineage shared the most recent common ancestor ( MRCA ) with specimens from A ngola, V enezuela, and N amibia, whereas eastern S outh A frican specimens and M ozambique grouped together, indicating a non‐sister relationship for the two S outh A frican lineages. Two plausible biogeographic scenarios to explain their origin were both supported by the hypotheses‐testing analysis. One includes an I ndo‐ P acific origin for P . perna , dispersal into the M editerranean and A tlantic through the Tethys seaway, followed by recent secondary contact after southward expansion of the western and eastern S outh A frican lineages. The other scenario ( O ut of S outh A frica) suggests an ancient vicariant divergence of the two lineages followed by their northward expansion. Nevertheless, the “Out of South Africa” hypothesis would require a more ancient divergence between the two lineages. Instead, our estimates indicated that they diverged very recently (310 kyr), providing a better support for an Indo‐Pacific origin of the two S outh A frican lineages. The arrival of the MRCA of P . perna in B razil was estimated at 10 [0–40] kyr. Thus, the hypothesis of a recent introduction in B razil through hull fouling in wooden vessels involved in the transatlantic itineraries of the slave trade did not receive strong support, but given the range for this estimate, it could not be discarded. Wider geographic sampling of marine organisms shows that lineages with contiguous distributions need not share a common ancestry.