Phylogeny and biogeography of the hyper diverse genus Eugenia (Myrtaceae: Myrteae), with emphasis on

Fiorella Fernanda Mazine (1), Jair Eustáquio Quintino Faria (2), Augusto Giaretta (3), Thais Vasconcelos (4), Félix Forest (5) & Eve Lucas (4)

(1) Universidade Federal de São Carlos, campus Sorocaba, Departamento de Ciências Ambientais, Rod. João Leme dos Santos (SP 264), km 110, 18052-780, Sorocaba – SP, Brazil

(2) Universidade de Brasília, Instituto de Ciências Biológicas, Departamento de Botânica, 70910-900, Brasília – DF, Brazil

(3) Universidade de São Paulo, Instituto de Biociências, Depto. Botânica, Lab. Sistemática Vegetal, R. do Matão 277, 05508-090, São Paulo – SP, Brazil

(4) Herbarium, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, U.K.

(5) Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3DS, U.K.

Author for correspondence: Fiorella Fernanda Mazine, fiorella@ufscar.br

Eugenia L., comprising ca. 1100 species, is the largest genus of Neotropical Myrtaceae. Eugenia sect. Umbellatae (formerly referred to as “clade 9”) is the most speciose lineage of Eugenia. This study aims to better delimit Eugenia sect. Umbellatae, to identify and understand relationships between manageable subgroups of this large clade for future discrete systematic studies and to explain biogeographical patterns in the genus. In total, 103 samples were used in this study. These include representatives of the nine clades of the ‘Eugenia group’ with a particular focus on Eugenia clade 9, representing the morphological and geographical diversity found in the genus. Phylogenetic reconstructions were performed using maximum likelihood (ML) and Bayesian inference (BI) for the combined dataset, using the markers ITS, rpL16, psbA-trnH, rpl32-trnL and trnQ-rps16). The resultant tree was fossil calibrated and used for historical biogeographical analysis using DEC implemented in RASP. The mid Oligocene is the most likely period in which the crown node of Eugenia s.l. diversified. The earliest Eugenia appear to be associated with dry biomes and to have arisen from non-tropical southern South America, as did ancestors of the earliest American Myrteae. Eugenia subg. Pseudeugenia also most likely diversified in dry biomes, while E. subg. Hexachlamys and E. subg. Eugenia are likely to have diverged in the Atlantic Forests biome. Eugenia sect. Umbellatae is morphologically very variable; some clades can be circumscribed based on morphology while some remain morphologically undiagnosable. The study presented here provides discussion of the earliest origins of Eugenia and its response to climate-driven changes in the Neotropics as humid, forest biomes became more widespread in the Miocene. In addition, important practical conclusions are drawn regarding relationships within Eugenia. Three clades are newly classified as subgenera: Eugenia subg. Pseudeugenia (including species of E. sect. Pseudeugenia); E. subg. Hexachlamys (including Eugenia sect. Hexachlamys) and E. subg. Eugenia (including E. sect. Umbellatae, E. sect. Jossinia, E. sect. Phyllocalyx, E. sect. Pilothecium, E. sect. Racemosae, E. sect. Schizocalomyrtus, E. sect. Speciosae and Eugenia sect. Excelsae). Two previously unidentified clades are published as Eugenia sect. Excelsae and recognized as Eugenia sect. Jossinia, the latter consisting entirely of Old World species.

Keywords. Atlantic Forest; Jossinia; Neotropics; Racemosae; Schizocalomyrtus; systematics