title: Historical biogeography of the highly diverse brown seaweed Lobophora (Dictyotales, Phaeophyceae).
abstract: The tropical to warm-temperate marine brown macroalgal genus Lobophora (Dictyotales, Phaeophyceae) recently drew attention because of its striking regional diversity. In this study we reassess Lobophora global species diversity, and species distributions, and explore how historical factors have shaped current diversity patterns. We applied a series of algorithmic species delineation techniques on a global mitochondrial cox3 dataset of 598 specimens, resulting in an estimation of 98-121 species. This diversity by far exceeds traditional diversity estimates based on morphological data. A multi-locus time-calibrated species phylogeny using a relaxed molecular clock, along with DNA-confirmed species distribution data was used to analyse ancestral area distributions, dispersal-vicariance-founder events, and temporal patterns of diversification under different biogeographical models. The origin of Lobophora was estimated in the Upper Cretaceous (-75 to -60 MY), followed by gradual diversification until present. While most speciation events were inferred within marine realms, founder events also played a non-negligible role in Lobophora diversification. The Central Indo-Pacific showed the highest species diversity as a result of higher speciation events in this region. Most Lobophora species have small ranges limited to marine realms. Lobophora probably originated in the Tethys Sea and dispersed repeatedly in the Atlantic (including the Gulf of Mexico) and Pacific Oceans. The formation of the major historical marine barriers (Terminal Tethyan event, Isthmus of Panama, Benguela upwelling) did not act as important vicariance events. Long-distance dispersal presumably represented an important mode of speciation over evolutionary time-scales. The limited geographical ranges of most Lobophora species, however, vouch for the rarity of such events.
authors.affiliation: ENTROPIE (IRD, UR, CNRS), LabEx-CORAIL, Institut de Recherche pour le Développement, B.P. A5, 98848 Nouméa Cedex, Nouvelle-Calédonie, France; Phycology Research Group and Center for Molecular Phylogenetics and Evolution, Ghent University, Gent B-9000, Belgium; Sorbonne Universités, UPMC Univ Paris 06, IFD, Paris F75252, France. Electronic address: cvcarp@gmail.com.
authors.forename: Christophe
authors.initials: C
authors.lastname: Vieira
authors.affiliation: Department of Biology, University of Louisiana at Lafayette, Lafayette, LA 70504-3602, USA.
authors.forename: Olga
authors.initials: O
authors.lastname: Camacho
authors.affiliation: Institute of Oceanology, Chinese Academy of Sciences, Department of Marine Organism Taxonomy and Phylogeny, China.
authors.forename: Zhongmin
authors.initials: Z
authors.lastname: Sun
authors.affiliation: Department of Biology, University of Louisiana at Lafayette, Lafayette, LA 70504-3602, USA.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Fredericq
authors.affiliation: Phycology Research Group and Center for Molecular Phylogenetics and Evolution, Ghent University, Gent B-9000, Belgium; Botanic Garden Meise, 1860 Meise, Belgium.
authors.forename: Frederik
authors.initials: F
authors.lastname: Leliaert
authors.affiliation: ENTROPIE (IRD, UR, CNRS), LabEx-CORAIL, Institut de Recherche pour le Développement, B.P. A5, 98848 Nouméa Cedex, Nouvelle-Calédonie, France.
authors.forename: Claude
authors.initials: C
authors.lastname: Payri
authors.affiliation: Phycology Research Group and Center for Molecular Phylogenetics and Evolution, Ghent University, Gent B-9000, Belgium.
authors.forename: Olivier
authors.initials: O
authors.lastname: De Clerck
mesh_terms: D000818:Animals; D044822:Biodiversity; D000459:Phaeophyceae / Q000145:classification*; D010802:Phylogeny; D058974:Phylogeography; D012624:Seaweed / Q000145:classification*; D013045:Species Specificity; D061350:Sympatry; D013997:Time Factors
keywords: Algorithmic species estimation; Ancestral area reconstruction; Historical biogeography; Lobophora; Molecular dating