J Syst Evol ›› 2021, Vol. 59 ›› Issue (1): 21-43.DOI: 10.1111/jse.12572

• Research Articles • Previous Articles     Next Articles

Evolution of reproductive traits in the mahagony family (Meliaceae)

Rebeca Laino Gama1* , Alexandra Nora Muellner‐Riehl2,3 , Diego Demarco1 , and José Rubens Pirani1   

  1. 1Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, Rua do Matão 277, Edifício Herbário (SPF), São Paulo 05508‐090, Brazil
    2Department of Molecular Evolution and Plant Systematics & Herbarium (LZ), Institute of Biology, Leipzig University, Johannisallee 21–23, Leipzig D‐04103, Germany
    3German Centre for Integrative Biodiversity Research (iDiv) Halle‐Jena‐Leipzig, Deutscher Platz 5e, Leipzig D‐04103, Germany
  • Received:2019-03-03 Accepted:2020-01-21 Online:2020-02-04 Published:2021-01-01

Abstract: Meliaceae are a mostly pantropical family in the Sapindales, bearing flowers typically provided with a staminal tube, formed by filaments that are fused partially or totally. Nevertheless, several genera of subfamily Cedreloideae have free stamens, which may be adnate to an androgynophore in some taxa. The fact that the family exhibits a wide diversity of floral and fruit features, as well as of sexual systems and pollination syndromes, presents interesting questions on the evolutionary processes that might have taken place during its history. In this study, we analyzed the distribution of 20 reproductive morphological traits of Meliaceae, upon an available molecular phylogenetic framework, using 31 terminals from the family's two main clades (Cedreloideae and Melioideae), plus six Simaroubaceae taxa as outgroup. We aimed to identify and/or confirm synapomorphies for clades within the family and to develop hypotheses on floral evolution and sexual systems in the group. Our reconstruction suggests that the ancestor of Meliaceae was possibly provided with united stamens and unisexual flowers in dioecious individuals, with a subsequent change to free stamens and monoecy in the ancestor of Cedreloideae. Most characters studied show some degree of homoplasy, but some are unique synapomorphies of clades, such as the haplostemonous androecium. An androgynophore defines the Cedrela‐Toona clade. The comparative approach of our study and the evolutionary hypotheses generated herein reveal several aspects demanding further structural investigation, and possible evolutionary pathways of the reproductive structures along with the lineages' diversification, mostly related to the specialization of sexual systems, floral biology, and dispersal strategies.

Key words: ancestral character state reconstruction, floral evolution, macroevolution, rosids, Sapindales, sexual systems, systematics