Author:
Madeira Pedro,Reddy Maggie M.,Assis Jorge,Bolton John J.,Rothman Mark D.,Anderson Robert J.,Kandjengo Lineekela,Kreiner Anja,Coleman Melinda A.,Wernberg Thomas,De Clerck Olivier,Leliaert Frederik,Bandeira Salomão,Ada Abdul M.,Neiva João,Pearson Gareth A.,Serrão Ester A.
Abstract
AbstractThe southern coast of Africa is one of the few places in the world where water temperatures are predicted to cool in the future. This endemism-rich coastline is home to two sister species of kelps of the genus Ecklonia maxima and Ecklonia radiata, each associated with specific thermal niches, and occuring primarily on opposite sides of the southern tip of Africa. Historical distribution records indicate that E. maxima has recently shifted its distribution ~ 70 km eastward, to sites where only E. radiata was previously reported. The contact of sister species with contrasting thermal affinities and the occurrence of mixed morphologies raised the hypothesis that hybridization might be occurring in this contact zone. Here we describe the genetic structure of the genus Ecklonia along the southern coast of Africa and investigate potential hybridization and cryptic diversity using a combination of nuclear microsatellites and mitochondrial markers. We found that both species have geographically discrete genetic clusters, consistent with expected phylogeographic breaks along this coastline. In addition, depth-isolated populations were found to harbor unique genetic diversity, including a third Ecklonia lineage. Mito-nuclear discordance and high genetic divergence in the contact zones suggest multiple hybridization events between Ecklonia species. Discordance between morphological and molecular identification suggests the potential influence of abiotic factors leading to convergent phenotypes in the contact zones. Our results highlight an example of cryptic diversity and hybridization driven by contact between two closely related keystone species with contrasting thermal affinities.
Funder
Fundação para a Ciência e a Tecnologia
Fundação para a Ciência e a Tecnologia,Portugal
South African National Research Foundation
Australian Research Council
The King Leopold III Fund for Nature Exploration and Conservation
Research Foundation Flanders
EU-Biodeversa BiodivRestore-253
Pew Marine Fellowship
Aga Khan Foundation
Publisher
Springer Science and Business Media LLC
Cited by
2 articles.
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