Abel Gizaw Seid
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Forfattere
Lucía D. Moreyra Alfonso Susanna Juan Antonio Calleja Jennifer R. Ackerfield Turan Arabacı Carme Blanco-Gavaldà Christian Brochmann Tuncay Dirmenci Kazumi Fujikawa Mercè Galbany-Casals Tiangang Gao Abel Gizaw Seid Iraj Mehregan Roser Vilatersana Juan Viruel Bayram Yıldız Frederik Leliaert Alexey P. Seregin Cristina RoquetSammendrag
Widely distributed plant genera offer insights into biogeographic processes and biodiversity. The Carduus-Cirsium group, with over 600 species in eight genera, is diverse across the Holarctic regions, especially in the Mediterranean Basin, Southwest Asia, Japan, and North America. Despite this diversity, evolutionary and biogeographic processes within the group, particularly for the genus Cirsium, remain underexplored. This study examines the biogeographic history and diversification of the group, focusing on Cirsium, using the largest molecular dataset for the group (299 plants from 251 taxa). Phylogenomic analyses based on 350 nuclear loci, derived from target capture sequencing, revealed highly resolved and consistent phylogenetic trees, with some incongruences likely due to hybridization and incomplete lineage sorting. Ancestral range estimations suggest that the Carduus-Cirsium group originated during the Late Miocene in the Western Palearctic, particularly in the Mediterranean, Eastern Europe, or Southwest Asia. A key dispersal event to tropical eastern Africa around 10.7 million years ago led to the genera Afrocarduus and Afrocirsium, which later diversified in the Afromontane region. The two subgenera of Cirsium—Lophiolepis and Cirsium—began diversifying around 7.2–7.3 million years ago in the Western Palearctic. During the Early Pliocene, diversification rates increased, with both subgenera dispersing to Southwest Asia, where extensive in situ diversification occurred. Rapid radiations in North America and Japan during the Pleistocene were triggered by jump-dispersals events from Asia, likely driven by geographic isolation and ecological specialization. This added further layers of complexity to the already challenging taxonomic classification of Cirsium.Keywords: Biogeography; Carduinae; Cirsium; Diversification; North Hemisphere; Target-enrichment; Taxonomy.
Forfattere
Juan Manuel Gorospe Eliska Zaveska Desalegn Chala Abel Gizaw Seid Felly Mugizi Tusiime Lovisa Gustafsson Lubomir Pialek Filip Kolář Christian Brochmann Roswitha SchmicklSammendrag
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Forfattere
Lucía D. Moreyra Cristina Roquet Alfonso Susanna Siri Birkeland Carme Blanco‐Gavaldà Christian Brochmann Desalegn Chala Mercè Galbany‐Casals Abel Gizaw Seid Juan Antonio CallejaSammendrag
ABSTRACT Aim We investigated the biogeographic history and diversification dynamics of Afrocarduus , an Afromontane–Afroalpine genus endemic to eastern Africa. We aimed to assess the roles of geographic isolation, habitat transitions, and ecological speciation in shaping current diversity. Location The Afromontane and Afroalpine regions of East Africa and Ethiopia are situated along the Great Rift Valley system. Taxon Afrocarduus (Compositae: Carduinae), a genus comprising 18 endemic species. Methods We conducted a comprehensive taxonomic and geographic sampling of Afrocarduus , generating data from 489 nuclear loci. Phylogenomic and biogeographic ancestral estimation analyses were performed to infer the evolutionary history and historical biogeography of the genus. Results Afrocarduus originated in the Afromontane zone of eastern Africa during the Late Miocene (~10.7 Ma), with major diversification events occurring in the Early Pleistocene (~2.3 Ma). Most dispersal events occurred between neighbouring massifs, though occasional long‐distance dispersal between disjunct mountain systems was detected. The Turkana Depression and the Great Rift Valley have acted as major biogeographic barriers. Phylogenetic structure shows distinct clades occupying different regions. Ecological divergence between Afromontane and Afroalpine environments contributed to speciation, with at least six independent adaptations to Afroalpine conditions and multiple cases of ecological reversal. Stem loss, a trait associated with alpine habitats, evolved convergently in two clades. Closely related species often segregate by elevation or microhabitat within the same massif. Main Conclusions The diversification of Afrocarduus has been shaped by a combination of historical climate change, geographic isolation, and ecological adaptation. Our results emphasise the importance of ecological speciation and habitat transitions in Afrotemperate plant evolution and highlight the need for further research on understudied Afromontane taxa, especially under the threat of ongoing climate change.