Format: ORAL

Salvatore Tomasello1,Kamil Konowalik2, Christoph Oberprieler3

1 Georg-August-University, Göttingen, Germany 2 Wroclaw University of Environmental and Life Sciences, Wroclaw, Poland 3 University of Regensburg, Regensburg, Germany

Species delimitation is particularly challenging in polyploid complexes pervaded by reticulate evolution. As allopolyploids are a mosaic of characters of their parental lineages, the simultaneous inference of the evolutionary history (allo- vs. auto-polyploidy) and delimitation of species is impracticable in those groups. For instance, the hybridogenic nature of allopolyploids violates the assumptions of the current DNA-based approaches for species delimitation. Leucanthemopsis (Giroux) Heywood is a genus of the Asteraceae, consisting of six to ten species and several infraspecific taxa, mainly distributed in the western Mediterranean Basin. It is a polyploid complex that includes montane, subalpine, and strictly alpine lineages, which are locally distributed in different mountain ranges of Western Europe and North Africa. We used a mixed approach including Sanger sequencing and high throughput sequencing of amplicons to gather information on single-copy nuclear markers and plastid regions. Nuclear regions were carefully tested for recombinants/PCR artifacts and for paralogy. Coalescent-based methods were used to delimit species among the diploids. For the polyploids, we first sorted homeologs of nuclear genes into parental subgenomes. Therefore, we inferred delimitation among the Iberian tetraploids treating subgenomes separately in the analyses. We corroborated results from the DNA-based approaches with evidence from morphometric analyses of leaf shapes and ecological niche modelling. Based on the results, diploid taxa found growing in the Eastern Iberian Peninsula constitute a single, heterogeneous complex. Concerning polyploids, the analyses inferred Iberian tetraploids as having a clear allopolyploid origins. At least two different polyploidization events gave rise to L.spathulifolia, endemic of calcareous outcrops in South-eastern Spain, on the one side, and to all other tetraploid Iberian taxa on the other.