Análise morfométrica do complexo Senegalia polyphylla (Leguminosae)

Abstract

Senegalia is a Pantropical genus that currently comprises 235 taxa that occurs in the tropics and subtropics areas of the Old and New Worlds. New analyses are showing new phylogenomic evidence for the non­monophyly of the genus. The delimitation of some Senegalia species is complex since there are overlap morphological characters used to delimit them. In this context, there are some complex of species in the Senegalia genus mentioned in the literature: Senegalia amazonica complex, S. berlandieri complex, S. burkei complex, S. greggii complex, S. martiusiana complex, S. polyphylla complex, S. riparia complex, S. tamarindifolia complex, and S. tenuifolia complex. The Senegalia polyphylla complex is composed of the species S. polyphylla, S. giganticarpa, S. rhytidocarpa, S. loretensis, S. kallunkiae e S. klugii. Morphometric analyses are being used in species complexes to clarify the identity of some taxa in Fabaceae. In this background, morphological parameters that clearly segregate the species of the Senegalia polyphylla complex are necessary or, if they are not present, another analysis or even synonymizations need to be made. Therefore, the aim of this study is to find morphological parameters that help in the delimitation of the species belonging to the S. polyphylla complex, trying to show the main vegetative, floral and fruit characteristics that help to separate these species. Seventy­one specimens belonging to the S. polyphylla complex were morphologically measured. Forty­two exomorphological traits were analyzed. A multivariate analysis (PCA) was performed. Aiming to find similarities between the variables in study, we performed the distance biplot. In this same logic, we select the firs 10 best variables in PCA results for each stage. Those variables were used to construct the species dendogram and the hierarchical cluster analysis (Two­way Cluster) were performed. Although our PCA analysis could found some promising character patterns in the taxa separation, they were not actually effective for the complete segregation of the species of the studied complex. The cluster analyses with vegetative traits were able to separate only S. kallunkiae and S. kluggii from the other species as well as showed that they are related to each other. On the other hand, the cluster analyses with floral and fruit characteristics indicated a mix of traits much more complicated than previously thought. Our morphometric analyses were not able to separate all the species belonging to S. polyphylla complex or point some congruence that could make possible to stablish a pattern to guide a synonimization between some species. As all species complex, it is to be expected that the clear and distinct separation of the taxa will be difficult, even considering that the present work has exhausted the morphological data sources which could corroborate the elucidation of distinctive characters for these species. This work points to the need to use other characters that can help distinguish these taxa.