title: Testing the island effect on phenotypic diversification: insights from the Hemidactylus geckos of the Socotra Archipelago.
abstract: Island colonization is often assumed to trigger extreme levels of phenotypic diversification. Yet, empirical evidence suggests that it does not always so. In this study we test this hypothesis using a completely sampled mainland-island system, the arid clade of Hemidactylus, a group of geckos mainly distributed across Africa, Arabia and the Socotra Archipelago. To such purpose, we generated a new molecular phylogeny of the group on which we mapped body size and head proportions. We then explored whether island and continental taxa shared the same morphospace and differed in their disparities and tempos of evolution. Insular species produced the most extreme sizes of the radiation, involving accelerated rates of evolution and higher disparities compared with most (but not all) of the continental groups. In contrast, head proportions exhibited constant evolutionary rates across the radiation and similar disparities in islands compared with the continent. These results, although generally consistent with the notion that islands promote high morphological disparity, reveal at the same time a complex scenario in which different traits may experience different evolutionary patterns in the same mainland-island system and continental groups do not always present low levels of morphological diversification compared to insular groups.
authors.affiliation: Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta, 37-49, 08003, Barcelona, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Garcia-Porta
authors.affiliation: Department of Zoology, National Museum, Prague, Czech Republic.
authors.forename: Jiří
authors.initials: J
authors.lastname: Šmíd
authors.affiliation: Center for Ecological Research and Forestry Applications (CREAF), Spanish National Research Council (CSIC), Campus of the Autonomous University of Barcelona, Cerdanyola del Vallès, 08193 Catalonia, Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Sol
authors.affiliation: Dipartimento di Scienze della Terra e dell'Ambiente, Università di Pavia, Via Ferrata 1, I-27100 Pavia, Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Fasola
authors.affiliation: Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta, 37-49, 08003, Barcelona, Spain.
authors.forename: Salvador
authors.initials: S
authors.lastname: Carranza
mesh_terms: D000818:Animals; D049628:Body Size; D019143:Evolution, Molecular; D049810:Genetic Speciation; D014644:Genetic Variation; D062312:Islands; D008116:Lizards / Q000033:anatomy & histology / Q000145:classification / Q000235:genetics*; D010641:Phenotype