Galápagos and Cocos Islands: Geographically Close, Botanically Distant

Trusty, Jennifer L.; Tye, Alan; Collins, Timothy M.; Michelangeli, Fabián A.; Madriz, Pablo; Francisco‐Ortega, Javier

doi:10.1086/662657

Cited by 11 publications

(16 citation statements)

References 75 publications

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“…The few phylogenies published for Galápagos plants suggest that continental ancestors may have colonized from many different areas including the Caribbean, Ecuador, Peru and Chile (Tye & Francisco‐Ortega, ; Trusty et al ., ). Phylogeographic and phylogenetic analyses revealed a single, independent dispersal event by Galvezia from the mainland to the Galápagos archipelago (Figs and ).…”

Section: Discussionsupporting

confidence: 93%

Evolutionary history of the endangered shrub snapdragon (Galvezia leucantha) of the Galápagos Islands

Guzmán

Heleno

Nogales

et al. 2016

Diversity and Distributions

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Aim The endangered Galápagos shrub snapdragon (Galvezia leucantha, Antirrhineae, Plantaginaceae) is restricted to small populations on four islands. In this study, we appraised results from taxonomy, genetics, phylogenetics, phylogeography and pollination ecology to reconstruct the evolutionary history of the genus Galvezia. Location Peru, continental Ecuador and Galápagos. Methods We sequenced the nuclear ribosomal ITS and two plastid regions, ndhF and ndhF‐rpL32, to infer the origin of Galvezia and patterns of colonization to and across the Galápagos archipelago, based on Bayesian inference and statistical parsimony analyses. To investigate genetic diversity and differentiation within G. leucantha, we screened the genome of six populations and obtained 194 AFLP fingerprints. Autogamy tests and pollination network analyses were performed to evaluate the colonization potential and to investigate the structure of the pollinators’ assemblage of Galvezia. Results Relationships of seven nucleotide‐substitution haplotypes and 11 nucleotide‐substitution ribotypes of Galvezia revealed monophyly for the Galapagos species. Dating estimates indicated divergence of the insular Galvezia lineage in the Middle‐Upper Pleistocene (0.66–0.09 Ma). In addition, distribution of genotypes (seven haplotypes, eight ribotypes) across the three continental species showed geographical differentiation, while low differentiation and distribution of G. leucantha. AFLP genetic diversity is relatively high (HT = 0.109), but a low proportion of the total allelic variance is attributed to variation among subspecies/islands (Hb = 0.035, hierarchical AMOVA: 3.77% of total variance). The endemic bee (Xylocopa darwinii) accounted for 87.30% of the floral visits to G. leucantha. Main conclusions We inferred a single origin for an insular lineage that colonized the Galápagos Islands from northern Peru in the Pleistocene. Recent colonization of the archipelago, Pleistocene land bridges between islands and active gene flow promoted by X. darwinii may account for the low‐moderate genetic differentiation of G. leucantha subspecies. An unusual pollination shift from ornithophily (hummingbirds on the continent) to entomophily (Xylocopa in the Galápagos Islands) is supported.

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Section: Discussionsupporting

confidence: 93%

Evolutionary history of the endangered shrub snapdragon (Galvezia leucantha) of the Galápagos Islands

Guzmán

Heleno

Nogales

et al. 2016

Diversity and Distributions

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“…Comparisons of putative relatives based on taxonomy have recently become possible by phylogenetic reconstructions, and the sister-group principle has been used to infer some characteristics of the most recent common ancestor of endemic species (Vargas, 2007). Unfortunately, there are only a few phylogenetic analyses of Galápagos plant groups available to address this issue, and those with a reliable sample do not show any tendency to loss of dispersability (Sánchez-del Pino, Motley & Borsch, 2012;Vargas et al, 2012; see also Trusty et al, 2012). A lineage-by-lineage reconstruction of sister-group relationships is needed on a considerable number of plant groups to test diaspore shifts.…”

Section: Loss Of Dispersabilitymentioning

confidence: 99%

Plant colonization across the Galápagos Islands: success of the sea dispersal syndrome

et al. 2014

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A new approach for investigating evidence for the capacity of plant colonization between islands and the success of plant morphological traits associated with seed dispersal is presented. As colonization is the result of dispersal and establishment, oceanic archipelagos provide an ideal spatio‐temporal system in which to analyse plant dispersal traits related to current distributions of species across islands. The Galápagos archipelago comprises 12 islands > 10 km2 that harbour 403 native angiosperms, of which 313 native species occupy lowland habitats that are present on all islands. We inferred the minimum number of colonization events within the archipelago for the species (289 lowland species) present on more than one island (floristic analysis). The distribution (number of islands) of species across the islands was slightly left‐skewed, with 58% of all lowland species being present on one to six islands. The success of dispersal syndromes (i.e. morphological trait sets of the diaspores associated with dispersal) favourable to inter‐island dispersal (medium‐distance dispersal, MDD) was also analysed (syndrome analysis). In particular, the 289 lowland species were classified into four dispersal groups (syndromes): sea (thalassochory), wind (anemochory), and animal interior (endozoochory) or animal exterior (epizoochory). Most species (N = 174, 55.6%), however, displayed no traits related to MDD (unspecialized diaspores). Analyses of the distribution of syndrome traits across the 289 lowland native species and 12 islands revealed that: (1) species with one or more of the four MDD syndromes did not have broader distributions than those with unspecialized diaspores; (2) species with sea dispersal traits were the most broadly distributed; and (3) a net loss of dispersability for diaspore traits (from non‐endemic natives to endemic species) was not supported for the whole flora by our analyses. In summary, our analyses showed that species with sea‐drifting diaspore traits were significantly associated with the success of plant colonization across the Galápagos Islands. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174, 349–358.

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“…Recent phylogenetic studies have demonstrated that the closest relatives of some island endemics are not always from the mainland but rather from neighboring islands (Sato et al 1999;Motley et al 2005;Harbaugh and Baldwin 2007;Andrus et al 2009;Namoff et al 2010), emphasizing the contributions of both continents and islands to insular biodiversity. Trusty et al (2012) recently investigated whether the plants of the Galápagos Archipelago and Cocos Island, which are each other's closest neighboring insular systems, show any such sister relationships. Using molecular phylogenetic data for all five genera of vascular plants with endemics in both island locations, Trusty et al (2012) demonstrated no evidence for any phylogeographical links between the islands.…”

Section: Introductionmentioning

confidence: 99%

“…Trusty et al (2012) recently investigated whether the plants of the Galápagos Archipelago and Cocos Island, which are each other's closest neighboring insular systems, show any such sister relationships. Using molecular phylogenetic data for all five genera of vascular plants with endemics in both island locations, Trusty et al (2012) demonstrated no evidence for any phylogeographical links between the islands. This lack of floristic affinity between Galápagos and Cocos was attributed primarily to atmospheric and ocean circulation patterns that likely limit dispersal between the two.…”

Section: Introductionmentioning

confidence: 99%

Origins of the Endemic Scaly Tree Ferns on the Galápagos and Cocos Islands

Kao

Pryer

Turner

et al. 2015

International Journal of Plant Sciences

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. The University of Chicago Press is collaborating with JSTOR to digitize, preserve and extend access to International Journal of Plant Sciences.Editor: Alan W. Meerow Premise of research. Successful long-distance dispersal is rarely observed in scaly tree ferns (Cyatheaceae). Nevertheless, recent molecular evidence has suggested that the four endemic scaly tree ferns on the Galápagos Archipelago (Cyathea weatherbyana) and Cocos Island (Cyathea alfonsiana, Cyathea nesiotica, and Cyathea notabilis), two oceanic island groups west of Central and northern South America, probably each originated from different mainland America ancestors. However, the phylogenetic relationships inferred among these endemics and their mainland relatives have been unclear. This study is aimed at better resolving the relationships and tracing the origins of these island endemics.Methodology. Five plastid regions from 35 Cyathea species were analyzed to reconstruct phylogenetic relationships using parsimony, likelihood, and Bayesian approaches. We also estimated divergence times of these species, and our chronogram was used to reconstruct their biogeographical range history.Pivotal results. Our well-resolved phylogenetic tree of Cyathea, which is in agreement with previous studies, shows that when the four Galápagos and Cocos endemics are included, they each belong to separate subclades. Our biogeographical study suggests that the four endemics originated from independent colonization events from mainland America and that there was no dispersal of Cyathea between the island groups. We reveal more detailed relationships among the endemics and their respective close mainland relatives; some of these relationships differ from previous studies. Our findings are corroborated by new morphological data from ongoing stem anatomy studies.Conclusions. The four scaly tree ferns endemic to the Galápagos and Cocos Islands each did indeed originate as independent colonization events from separate sources in mainland America, and their closest relatives are identified here.

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Galápagos and Cocos Islands: Geographically Close, Botanically Distant

Cited by 11 publications

References 75 publications

Evolutionary history of the endangered shrub snapdragon (Galvezia leucantha) of the Galápagos Islands

Evolutionary history of the endangered shrub snapdragon (Galvezia leucantha) of the Galápagos Islands

Plant colonization across the Galápagos Islands: success of the sea dispersal syndrome

Origins of the Endemic Scaly Tree Ferns on the Galápagos and Cocos Islands

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