Abstract Detail

Systematics

De Luca, Daniele [1], Del Guacchio, Emanuele [2], Cennamo, Paola [3], Caputo, Paolo [1].

Picking knapweeds in the Siren Land: the narrow endemic Centaurea tenorei group (Asteraceae, Cardueae).

The genus Centaurea L. is one of the most widespread, differentiated, and critical genera of Asteraceae in the Euro-Mediterranean area, with more than 100 currently recognized species. The controversial C. tenorei group, narrow endemic to the Peninsula of Sorrento (Campania region, southern Italy), includes three weakly differentiated microspecies: C. tenorei Guss. ex Lacaita, C. montaltensis (Fiori) Peruzzi and C. lacaitae Peruzzi. However, their taxonomic distinctness and relationships with close or sympatric species are still unclear. In particular, the existence in several localities of individuals with intermediate morphology suggests inadequate taxonomic assessment within the group or hybridization and introgression with further species. In this study we aimed at defining population structure and delimitating taxa in this complex. With this objective, we sampled the three currently accepted species from their loci classici and other localities throughout the range, also including populations of difficult identification occurring where the ranges of different taxa overlap. In addition, we sampled material from the following related taxa: C. aeolica Guss. ex Lojac. subsp. aeolica, C. aeolica Guss. ex Lojac. subsp. pandataria (Bég. & Fiori) Anzal., C. ambigua Guss. subsp. ambigua, C. cineraria L. subsp. cineraria, C. deusta Ten. subsp. deusta, and C. deusta subsp. leucolepis (DC.) Del Guacchio, Cennamo & P.Caputo. We employed a panel of over 35,000 SNPs obtained via genotyping-by-sequencing for investigations on structure, introgression, and species boundaries. Population structure analyses indicated the presence of four to seven clusters, most of which with evidence of admixture. A population of difficult identification resulted to be formed by both individuals belonging to the C. tenorei group and individuals referable to C. cineraria (out of its ecological range); in addition, one specimen was attributed to C. ×cavarae Guadagno ex Del Guacchio, Cennamo et P.Caputo, a recently described hybrid between C. montaltensis and C. deusta subsp. deusta. The ABBA-BABA test detected gene flow between various of the sampled populations. In no case, however, recent hybridization/introgression was documented outside the three microspecies object of this investigation. Some of the admixed populations showed signatures of ancient introgression. Bayesian species delimitation will support a novel arrangement of taxa.

1 - University of Naples Federico II, Department of Biology, Via Foria 223, Naples, 80139, IT
2 - Botanic Garden, Via Foria 223, Naples, 80139, IT
3 - University of Naples Suor Orsola Benincasa, Department of Humanities, Via Santa Caterina da Siena 37, Naples, 80132, IT

Keywords:
Asteraceae
Centaurea
Genotyping-by-Sequencing
Mediterranean area
species complex.

Presentation Type: Oral Paper
Session: SYSTI, Systematics I: Euasterids II
Location: Virtual/Virtual
Date: Tuesday, July 20th, 2021
Time: 10:00 AM(EDT)
Number: SYSTI001
Abstract ID:551
Candidate for Awards:None