Origins of the endemic scaly tree ferns on the galápagos and Cocos Islands
Abstract
© 2015 by The University of Chicago. All rights reserved. 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.
Type
Journal articleSubject
Science & TechnologyLife Sciences & Biomedicine
Plant Sciences
Cyathea
Cyatheaceae
island biogeography
phylogenetic analysis
rbcL
rbcL-accD
rbcL-atpB
trnG-R
trnL-F
GEOGRAPHIC RANGE
EVOLUTION
CYATHEACEAE
PHYLOGENY
DISPERSAL
BIOGEOGRAPHY
INFERENCE
ALIGNMENT
PATTERNS
FLORA
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https://hdl.handle.net/10161/21756Published Version (Please cite this version)
10.1086/683303Publication Info
Kao, T; Pryer, KM; Turner, MD; White, RA; & Korall, P (2015). Origins of the endemic scaly tree ferns on the galápagos and Cocos Islands. International Journal of Plant Sciences, 176(9). pp. 869-879. 10.1086/683303. Retrieved from https://hdl.handle.net/10161/21756.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Kathleen M. Pryer
Professor of Biology

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