Phylogeny, biogeography, and the evolution of life-history traits in Leucadendron (Proteaceae).
Leucadendron is a moderately large genus of Proteaceae almost entirely restricted to the Cape Floristic Region of southern Africa. The genus is unusual in being dioecious and sexually dimorphic. ITS sequence data were obtained from 62 of the 96 currently recognized taxa (85 species and 11 subspecies). Phylogenetic analyses were conducted under Maximum Likelihood and parsimony and resolved nine groups of species with varying degrees of bootstrap support, but relationships between these groups are largely unsupported. The phylogeny conflicts with the current taxonomic arrangement, which is based mainly on fruit morphology. The two sections of the genus, Alatosperma and Leucadendron, and several subsections within these sections, are resolved as non-monophyletic. This means that taxonomically important characters (such as fruit shape) have evolved multiple times, as the species with nut-like fruit (resolved into two of the nine groups) appear to have evolved independently from ancestors with winged fruit. Based on the topology obtained, the life history traits of anemophily, myrmechochory, and re-sprouting have also originated multiple times. Dispersal-Vicariance (DIVA) analysis suggests that the genus had an ancestral area in the Karoo Mountain and Southeastern phytogeographic centres of endemism in the southwestern Cape.
Barker
Nigel P
NP
Molecular Ecology and Systematics Group, Department of Botany, Rhodes University, PO Box 94, Grahamstown 6140, South Africa. n.barker@ru.ac.za
Vanderpoorten
Alain
A
Morton
Cynthia M
CM
Rourke
John P
JP
D005075:Biological Evolution; D004247:DNA / Q000235:genetics; D021903:DNA, Ribosomal Spacer; D019143:Evolution, Molecular; D005843:Geography; D016013:Likelihood Functions; D010802:Phylogeny; D011058:Pollen; D039105:Proteaceae / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013997:Time Factors
D021903:DNA, Ribosomal Spacer; D004247:DNA