Abstract Detail

Floristics & Taxonomy

Paredes-Burneo, Diego [1], Michelangeli, Fabian [2], Lagomarsino, Laura [3].

Exploring what’s behind taxonomical complexes: a case with Brachyotum (Melastomataceae) in the Andes.

Brachyotum (Melastomataceae) is a genus endemic to the Andes with 55 species occurring from Colombia to Argentina, mostly above the treeline (between 3000 to 3500 m). It is easily recognized for its free, overlapping petals that form a tubular flower that are thought to be pollinated by hummingbirds. Even though identifying this genus is straightforward, several species are hard to discriminate from each other. What is behind this taxonomical problem seems to be an intricate evolutionary history: putative hybrids have been identified that involve narrowly endemic species. Additionally, they inhabit grasslands of the paramo, puna and jalca, the youngest ecosystems in the Andes. Before solving this evolutionary issue, the first step involves getting to know how species are distributed along these mountains, as well as listing the putative hybrids and taxonomical complexes. Here, we tackle these questions by using information available on GBIF, virtual herbaria and literature to elaborate occurrence and richness maps on QGIS 3.10. Although Brachyotum occurs from the Andes of Colombia to northern Argentina, the highest diversity is concentrated between southern Ecuador and northern Peru where, according to richness analyses, in 1°x1° grids it is possible to find between 16 to 22 species. Narrow endemism is most common across Brachyotum: of the 31 species native to Peru—the country with most of the species—23 are endemic. Based on herbarium surveys, it seems that, B. rostratum (a widely distributed species in the Peruvian Andes) is the species that may commonly interbreeds with many narrowly endemic species (such as B. angustifolium, B. longisepalum, among others) to form potential hybrids, morphological evidence suggests. These results, which demonstrate that species are restricted to young, fragmented habitats, especially in northern Peru, point to the uplift of the Andes as a likely driver of evolution in Brachyotum and suggest that this group likely represents a rapid Andean radiation. Hybridization, likely due to secondary contact and promoted by the Pleistocene glacial periods, may have also been an important factor for some species, and is the main cause of confusion in taxonomic complexes.

1 - Louisiana State University, Department Of Biological Sciences, 202 Life Sciences Building, Baton Rouge, LA, 70803, United States
2 - The New York Botanical Garden, 2900 Southern BLVD, Bronx, NY, 10458, United States
3 - Louisiana State University, Dept Of Biological Sciences, 103 Life Sciences Building, Baton Rouge, LA, 70803, United States

Andean evolution

Presentation Type: Oral Paper
Session: FT1, Floristics & Taxonomy I
Location: Virtual/Virtual
Date: Monday, July 27th, 2020
Time: 11:15 AM
Number: FT1FT006
Abstract ID:668
Candidate for Awards:None

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