Diversification of a large genus in a continental biodiversity hotspot: temporal and spatial origin of Muraltia (Polygalaceae) in the Cape of South Africa.

摘要: Phylogenetic relationships in the largely South African genus Muraltia (Polygalaceae) are assessed based on DNA sequence data (nuclear ribosomal ITS, plastid atpB-rbcL spacer, trnL intron, and trnL-F spacer) for 73 of 117 currently recognized species genus. The previously recognised subgenus is monophyletic, but endemic Nylandtia embedded Psiloclada. Subgenus found to be sister Estimates show beginning diversification two subgenera early Miocene (Psiloclada, 19.3+/-3.4 Ma; Muraltia, 21.0+/-3.5 Ma) pre-dating establishment Benguela current (intermittent middle late Oligocene markedly intensifying Miocene), summer-dry climate Cape region. However, later increase numbers contemporaneous with these climatic phenomena. Results dispersal-vicariance analyses indicate that major clades diversified from southwestern northwestern Cape, where most today.