Carolina Prandi Silva‡, Rafael Felipe Almeida§, Eduardo Gasparino‡Corresponding author: Carolina Prandi Silva ( carolinaprandi32@gmail.com ) © Carolina Prandi Silva, Rafael Felipe Almeida, Eduardo Gasparino. This is an open access preprint distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Citation:
Silva CP, Almeida RF, Gasparino E (2023) Evolution of pollen grain morphology in Amorimia W.R. Anderson and allies (Malpighiaceae). ARPHA Preprints. https://doi.org/10.3897/arphapreprints.e101880 |  |
Background and aims: The genus Amorimia W.R. Anderson (Malpighiaceae), was recently segregated from species previously treated as the genus Mascagnia Bertero and then subdivides into two subgenera Amorimia subgenus Amorimia and Amorimia subgenus Uncinae, based on morphological and molecular data. Pollen grains have been used to improve the taxonomic classification of many ranks (i.e., species, genus, family) over the past two centuries. The pollen grains of the species of Amorimia were not previously analyzed. Therefore, we descibe in detail the pollen morphology of 13 (out of 15) species of Amorimia, 1 species of Mascagnia Bertero and 1 species of Ectopopterys W.R. Anderson and reconstruct the phylogeny framework to understand the patterns of micromorphological pollen evolution in the genus.
Material and Methods: The pollen grains were acetolysed, measured and photographed under light microscope. The quantitative data were submited to a multivariate analysis and were also made a character-mapping to identify which pollen characters are important in distinguishing species.
Key Results: The pollen grains of the analyzed species are monads, apolar, medium to large, with circular amb, oblate-spheroidal to prolate-spheroidal, presenting apertures that may be 3-colporate, with long and narrow colpi and circular endoaperture (Ectopopterys), 6- porate (Amorimia) or 8-porate (Mascagnia). Exine presenting a rugulate ornamentation which may or may not have areolate or psilate areas close to the pore or distributed by the surface of the pollen grain.
Conclusion: According to the results of this study, Amorimia is a stenopolinic genus and the characteristics of the pollen grains are importante to segregate the genus. Nonetheless, there characteristics do not corroborate with the subdivision of this genus.