Cremastosperma ; phylogeny and biogeography of Neotropical Annonaceae

Michael D. Pirie
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My PhD project (Pirie, 2005a; online version ), supervised by Prof. Paul J.M. Maas and Dr. Lars W. Chatrou at the Utrecht branch of the National Herbarium of the Netherlands, focussed on the genus Cremastosperma, which is found in the South and Central American tropics. A taxonomic revision of Cremastosperma was made. Twenty-nine species were recognised, 13 of which were new to science (Chatrou & Pirie, 2003; Pirie & Zapata C., 2004; Pirie, 2005b). Most of the species of Cremastosperma are found along the foothills of the Andes. They are often narrow endemics, found only in areas such as the valleys of the Magdalena River in Colombia, and Marañon in Peru. DNA sequences were compared in order to reconstruct the phylogeny of 19 of the 29 species of Cremastosperma. Clades were revealed which included species distributed either west or east of the Andes mountain chain , providing further evidence to suggest the importance of the Andean orogeny as a vicariance event in the history of the evolution of Cremastosperma.
Many other groups of plants share this ‘Andean-centred’ distribution, and the rising of the Andean mountain chain has thus been hypothesised to have caused the origin of a large proportion of the high biodiversity of the New World tropics (Gentry, 1982). DNA sequences were used to reconstruct the relationships between species of four Andean-centred genera of Annonaceae, Cremastosperma, Klarobelia, Malmea and Mosannona, and to estimate how long ago those species shared common ancestors. The conclusion was drawn that the Andean-centred distribution patterns as observed are not the arbitrary result of the definition of poly- or paraphyletic groups. The timing of species diversifications in these groups was shown to coincide with the rise of the northern Andes, within the last 20-30 million years (Pirie et al., in press).
The timing of diversifications in Cremastosperma and Mosannona were compared with those in two more widely distributed and species rich genera, Duguetia and Guatteria, assessing the effects of taxon and character sampling on date estimates (Pirie et al., 2005). Additionally, an ancient paralogue of the widely used chloroplast marker trnL-F was discovered, the origin of which was inferred to have taken place in a common ancestor of the Annonaceae (Pirie et al., submitted).

I continue an active interest in the systematics and biogeography of particularly Neotropical Annonaceae.

References
Chatrou, L. W., & Pirie, M. D. 2003. Two new species of Annonaceae from Bolivia. Rev. Soc. Bol. Bot. 4: 25-30.
Gentry, A. H. 1982. Neotropical floristic diversity: phytogeographical connections between Central and South America, Pleistocene climatic fluctuations, or an accident of the Andean orogeny? Ann. Missouri Bot. Gard. 69: 557-593.
Pirie, M. D. 2005a. Cremastosperma (and other evolutionary digressions): Molecular phylogenetic, biogeographic, and taxonomic studies in Neotropical Annonaceae. Ph.D. thesis. Utrecht University, the Netherlands. - online version
Pirie, M. D. 2005b. New species of Cremastosperma (Annonaceae) from Colombia, Ecuador, and Panama. Blumea 50: 41-60.
Pirie, M. D., Balcázar Vargas, M. P., Botermans, M., Bakker, F. T., & Chatrou, L. W. submitted. Duplication of the cpDNA trnL (UAA)-trnF (GAA) region in Annonaceae and its application in phylogeny reconstruction. Molec. Phylog. Evol.
Pirie, M. D., Chatrou, L. W., Erkens, R. H. J., Maas, J. W., Van der Niet, T., Mols, J. B., & Richardson, J. E. 2005. Phylogeny reconstruction and molecular dating in four Neotropical genera of Annonaceae: the effect of taxon sampling in age estimations. In: Plant species-level systematics: new perspectives on pattern and process (Bakker, F. T., Chatrou, L. W., Gravendeel, B., and Pelser, P. B., eds.). Regnum Vegetabile 143, A. R. G. Gantner Verlag, Liechtenstein, pp. 149-174
Pirie, M. D., Chatrou, L. W., Mols, J. B., Erkens, R. H. J., & Oosterhof, J. in press. 'Andean-centred' genera in the short-branch clade of Annonaceae: Testing biogeographic hypotheses using phylogeny reconstruction and molecular dating. J. Biogeogr.
Pirie, M. D., & Zapata C., M. 2004. Three new endemic species of Cremastosperma (Annonaceae) from the Río Marañon basin, Amazonas, Peru. Arnaldoa 11(2): 7-20.