SSK-Project 2009 Aylostera-Mediolobivia
Previous Results
The results of our molecular biological studies (Ritz et al. 2007) show that the genus Rebutia is not monophyletic. Rebutia sensu lato is not a natural kinship. Our phylogenetic tree rather reflects the subdivision of the Rebutia in three separate genera Aylostera, Mediolobivia, and Rebutia as adopted by Backeberg (1977) in the sense of Krainz (1967). In our study Rebutia (sensu Backeberg) is represented by two taxa with hairless pericarpels: the type species R. minuscula K. Schum. and R. padcayensis (Rausch) that are located along with Sulcorebutia und Weingartia on branch E in our tree. The species with hairy or bristly pericarpels (Aylostera and Mediolobivia sensu Backeberg) form branch D. Within this branch three subgroups can be identified:
- R. pseudodeminuta Backeb., R.fiebrigii (Gürke) Britton & Rose and R. deminuta (F.A.C. Weber) Britton & Rose (Aylostera in Backeberg's classification)
- R. pygmaea (R.E.Fr.) Britton & Rose R. steinmannii (Solms) Britton & Rose
- R. einsteinii Fric.
Concept Aylostera-Mediolobivia 2009
The objective is to investigate the infra-generic relationships in branch D (highlighted in yellow in our tree) with the groupings Aylostera and Mediolobivia (sensu Backeberg) with molecular biological methods.
In continuation of our previous work we aim to answer following questions:
- Is it possible to separate the genera from Aylostera and Mediolobivia each other?
- Are morphological characters and genetic data compatible?
- Do we find a geographic pattern within the data that may allow us to reconstruct the evolution and the dispersal history of the complex?
Our hitherto experience has shown that sequence analysis alone resolves the affinities only insufficinetly. On the other hand the AFLP® method reaches its limits when individuals under investigation are related relatively distant. Therefore, it is necessary to create a phylogeny with described species as a framework and examine the results with the AFLP® method. This approach requires a sampling that keeps the geographical gaps between the populations as small as possible while the entire known range needs to be covered as regularly as possible.
Contact:
References:
BACKEBERG, C. 1977. Das Kakteenlexikon. Gustav Fischer Verlag, Jena.
KRAINZ, H. 1967. Die Kakteen: eine Gesamtdarstellung der eingeführten Arten nebst Anzucht- und Pflege-Anweisungen. Franckh'sche Verlagshandlung, Stuttgart.
RITZ, C. M., L. MARTINS, R. MECKLENBURG, V. GOREMYKIN und F. H. HELLWIG. 2007. The molecular phylogeny of Rebutia (Cactaceae) and its allies demonstrates the influence of paleogeography on the evolution of South American mountain cacti. American Journal of Botany 94: 1321-1332.
This project is conducted in collaboration with the Department of Systematic Botany, University of Giessen, Germany. It is financed by the members of the SSK.
