The Cape element in the Afrotemperate flora: from Cape to Cairo?
Proc Biol Sci
; 274(1609): 535-43, 2007 Feb 22.
Article
em En
| MEDLINE
| ID: mdl-17476774
ABSTRACT
The build-up of biodiversity is the result of immigration and in situ speciation. We investigate these two processes for four lineages (Disa, Irideae p.p., the Pentaschistis clade and Restionaceae) that are widespread in the Afrotemperate flora. These four lineages may be representative of the numerous clades which are species rich in the Cape and also occur in the highlands of tropical Africa. It is as yet unclear in which direction the lineages spread. Three hypotheses have been proposed (i) a tropical origin with a southward migration towards the Cape, (ii) a Cape origin with a northward migration into tropical Africa, and (iii) vicariance. None of these hypotheses has been thoroughly tested. We reconstruct the historical biogeography of the four lineages using likelihood optimization onto molecular phylogenies. We find that tropical taxa are nested within a predominantly Cape clade. There is unidirectional migration from the Cape into the Drakensberg and from there northwards into tropical Africa. The amount of in situ diversification differs between areas and clades. Dating estimates show that the migration into tropical East Africa has occurred in the last 17 Myr, consistent with the Mio-Pliocene formation of the mountains in this area.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Magnoliopsida
/
Biodiversidade
/
Especiação Genética
Tipo de estudo:
Prognostic_studies
País como assunto:
Africa
Idioma:
En
Ano de publicação:
2007
Tipo de documento:
Article