Morphological homogeneity, phylogenetic heterogeneity and systematic complexity in species-rich groups : a case study of floral evolution in Myrteae (Myrtaceae)

Myrteae is the most diverse tribe in the species-rich angiosperm family Myrtaceae. Myrteae species play a critical ecological role in tropical forests and savannas, biomes with some of the highest biodiversity on earth. Hence there is a growing interest in its use as a model for evolutionary, ecological and conservation studies. However, morphologically homogeneous reproductive structures cause taxonomic instability and jeopardize modelling and conservation initiatives. This study demonstrates how evolutionary patterns are underpinned by floral traits in Myrteae. Aims are approached using combined phylogenetic and morphological analyses in two work packages (WP): WP1 increases understanding of systematics and floral evolution in Myrteae based on multiloci molecular matrices for a near complete generic sample. The framework is used to interpret biogeography, diversification and over-arching patterns of floral morphology and development; data are reciprocally combined to illuminate those processes. WP2 presents four case studies using floral development and multidimensional trait analysis to address questions related to systematic complexity, phylogenetic heterogeneity and theoretical cladistics concepts, such as evolution of homoplastic traits. Results harness Myrteae as a model group to address relevant questions in plant evolution and systematics; the applicability of this approach to similar questions in other diverse tropical angiosperm groups is discussed.