Abstract Detail


Nicolas, Antoine [1], Alfaro, Bryan [2], Babio, Lucas [2], Ferraro, Justin [2], Franklin, Sean [2], Nair, Harikrishnan [2], Plunkett, Gregory [3].

Molecular assessment of the Azorella multifida complex and its diversification within humid upper Andean habitats.

As currently circumscribed, Azorella (Azorelloideae, Apiaceae) includes c. 60 species of mats, cushions, and herbs that thrive in South and Central America, New Zealand, Australia, and subantarctic islands. Andes Mountains are centers of high diversification for the genus, especially in habitats above 3000 m that are humid for most of the year (e.g., páramos, jalcas, and moist punas). Major geologic and climatic changes made the flora of these areas more prone to hybridization and/or isolation, thus increasing the likelihood of high endemism and the presence of species and populations with unique genetic makeup. Páramos and similar tropical montane habitats face imminent threats from global warming, urbanization, and fragmentation, which makes the assessment of their genetic diversity particularly important for conservation purposes. This study focuses on the seven species of Azorella section Pectophytum, with emphasis on the four species of the Azorella multifida complex that thrive in high-elevation, humid habitats of the Andes. Due to the young age of these habitats, the high likelihood of reticulation, and the lack of comprehensive structural and molecular studies on these species, we hypothesize that current circumscriptions of the species are artificial and underestimate the number of species within the group. Fifty-six specimens from all seven species in the section were sampled, covering the geographic distribution and morphological variants within each species. Whole chloroplast genomes, complete nuclear rDNA region, and nuclear SNPs were used to assess phylogenetic relatedness and genetic diversity. Results showed two major clades in the A. multifida complex: one with A. corymbosa, A. pedunculata, and A. multifida and another with A. pulvinata and A. multifida. Of the four species, A. pedunculata and A. corymbosa appear to have lower genetic and morphological diversity, albeit with evidence of incomplete lineage sorting. A. pulvinata and especially A. multifida showed extensive reiterative polyphyly, thus highlighting the need to resolve weak species boundaries and conduct deeper studies on genetically-distinct populations. While some phylogenetic patterns can be explained biogeographically, leaves appear to exhibit distinct morphologies that may be used to identify subclades and putative new species. Section Pectophytum showed a south to north path of diversification, dispersing from Patagonia and then successively into Bolivia, Peru, Ecuador, and Colombia.

1 - Manhattan College, Biology, Leo Building - Room 317D, 4513 Manhattan College Parkway, Riverdale, NY, 10471, United States
2 - Manhattan College, Biology
3 - New York Botanical Garden, Cullman Program For Molecular Systematics, 2900 Southern Blvd., Bronx, NY, 10458, United States

Species Complex.

Presentation Type: Oral Paper
Session: PHYL3, Phylogenomics III
Location: Virtual/Virtual
Date: Friday, July 31st, 2020
Time: 11:00 AM
Number: PHYL3005
Abstract ID:692
Candidate for Awards:None

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