Geographical structure of morphology and spectral diversity in Arumãs (Ischnosiphon Körn. Marantaceae)
Abstract
Recognition and delimitation of taxonomic categories of biological organisms are still challenging and full of controversies. Traditional categorization of species may hamper the continuous variation of entities in nature. The assessment of morphometric and spectral variation of individuals along geographical and environmental gradients can be used to understand how homogeneous or grouped is the variation and may underscore the delimitation of natural units. We used Ischnosiphon (Marantaceae) as a model due to its great morphological variation and broad distribution. Species of this genus are terrestrial rhizomatous herbs, occurring in the understories of tropical forests from Nicaragua to southern Bolivia and Brazil. Here we apply an individual-based approach to test how variation of 22 wide to narrowly distributed species of Ischnosiphon is related to ecological factors and geographical distribution, besides describing morphological and spectral variation patterns. We demonstrate great diversity and morphological complexity among Ischnosiphon, and propose a replicable and analytical framework to accommodate individual variability in species diagnosis on morphologically diverse plant groups. Additionally, we show that range size is not a good predictor of phenotypic variance and that climatic distance is often more relevant to morphological and spectral variation than geographic distance. These results provide evidence of how our interpretation and recognition of species is prone to underestimation of the role of individual variability, and how environmental gradients influence phenotypic variation of widely distributed organisms. Finally, we discuss the relevance of phenotypic variability explorations on systematics, evolutionary and ecological studies.
Collections
The following license files are associated with this item: