Hawai'i, historical biogeography, Cibotium, spore dispersal, molecular phylogenetics, tree ferns
In the current study, using molecular phylogenetics, we evaluated the biogeographical history of the genus Cibotium, which includes four Hawaiian endemic species, in light of the four weather/climate-based dispersal mechanisms.
The monophyletic tree fern genus Cibotium (Cibotiaceae) (Korall et al.
Fosberg (1948), who hypothesized geographic origins for the original colonizing ancestors of native Hawaiian ferns and lycophytes, hypothesized one colonizing ancestral species for Hawaiian Cibotium that probably originated in the Indo-Pacific, but he could not rule out the possibility of an American origin.
All nine species of Cibotium were sampled in this study, as well as three outgroup species chosen based on relationships revealed by Korall et al.
Our results indicated that, based on plastid data alone, Cibotium was strongly supported as monophyletic and most relationships among the Cibotium species were strongly supported (posterior probability, PP = 1.
Within Cibotium, there were three strongly supported clades that correspond to the geographic distributions of the included species: the Asian clade, with three species, was sister to a clade with the four Hawaiian species in one subclade, and the two Mesoamerican species in the other.
The goals of this study were to determine if the Hawaiian species of Cibotium are monophyletic and to determine the relationships among species of Cibotium to infer the biogeographical history of the Hawaiian species.
The four endemic Hawaiian Cibotium species comprise a well-supported clade (Fig.
As stated above, we are unable to eliminate either Asia or Mesoamerica as the source area of the Cibotium spores that colonized the Hawaiian Islands based on the topology presented here.
First, although extant species of Cibotium seem to favor somewhat higher elevations (500-2500 m], for example in submontane forests (Large and Braggins, 2004), all of the Hawaiian species are reported to occur at 250 m or lower, and C.