J Syst Evol ›› 2021, Vol. 59 ›› Issue (4): 642-667.DOI: 10.1111/jse.12731

• Research Articles • Previous Articles     Next Articles

Geographical vs. ecological diversification in Carex section Phacocystis (Cyperaceae): Patterns hidden behind a twisted taxonomy

Carmen Benítez-Benítez1*, Santiago Martín-Bravo1, Charlotte S. Bjorå2, Sebastian Gebauer3, Andrew L. Hipp4,5, Matthias H. Hoffmann3, Modesto Luceño1, Tyril M. Pedersen2, Anton Reznicek6, Eric Roalson7, Polina Volkova8,9, Okihito Yano10, Daniel Spalink11†, and Pedro Jiménez-Mejías12†   

  1. 1Botany Area, Department of Molecular Biology and Biochemical Engineering, Universidad Pablo de Olavide, Ctra de Utrera km 1 sn, Seville 41013, Spain
    2Natural History Museum, University of Oslo, P.O. Box 1172 Blindern, Oslo 0318, Norway
    3Martin Luther University Halle‐Wittenberg, Geobotany and Botanical Garden, Am Kirchtor 3, Halle 06108, Germany
    4The Morton Arboretum, 4100 Illinois Route 53, Lisle, IL 60532, USA
    5The Field Museum, 1400S Lake Shore Dr, Chicago, IL 60605, USA
    6University of Michigan Herbarium, 3600 Varsity Dr, Ann Arbor, MI 48108‐2228, USA
    7School of Biological Sciences, Washington State University, Pullman, WA 99164, USA
    8Moscow South‐West High School, Moscow, Russian Federation
    9Papanin Institute for Biology of Inland Waters RAS, Borok, Yaroslavl Region 152742, Russia
    10Faculty of Biosphere‐Geosphere Science, Okayama University of Science, Okayama 700‐0005, Japan
    11Department of Ecology and Conservation Biology, Texas A&M University, 534 John Kimbrough Blvd, College Station, TX 77943, USA
    12Department of Biology, Universidad Autónoma de Madrid, Campus Cantoblanco, Madrid 28049, Spain
  • Received:2020-08-28 Accepted:2021-01-14 Online:2021-02-03 Published:2021-07-01

Abstract: Carex section Phacocystis (Cyperaceae) is one of the most diverse and taxonomically complex groups of sedges (between 116 and 147 species), with a worldwide distribution in a wide array of biomes. It has a very complicated taxonomic history, with numerous disagreements among different treatments. We studied the biogeography and niche evolution in a phylogenetic framework to unveil the relative contribution of geographical and ecological drivers to diversification of the group. We used a large species sampling of the section (82% of extant species) to build a phylogeny based on four DNA regions, constrained with a phylogenomic HybSeq tree and dated with six fossil calibrations. Our phylogenetic results recovered section Phacocystis s.s. (core Phacocystis) as sister to section Praelongae. Ancestral area reconstruction points toward the N Pacific as the cradle for the crown diversification of section Phacocystis during the Middle Miocene. Wide distributions were recurrently inferred across deep nodes. Large Northern Hemisphere lineages with geographical congruence were retrieved, pointing toward the importance of allopatric divergence at deep phylogenetic levels, whereas within-area speciation emerges as the predominant pattern at shallow phylogenetic level. The Southern Hemisphere (Neotropics, SW Pacific) was colonized several times from the Northern Hemisphere. The global expansion of Carex section Phacocystis did not entail major ecological changes along the inner branches of the phylogeny. Nevertheless, ecological differentiation seems to gain importance toward recent times.

Key words: allopatric speciation, biogeographic stochastic mapping, biogeography, biome, niche evolution, phylogeny, sedges, sympatric speciation