J Syst Evol ›› 2018, Vol. 56 ›› Issue (6): 576-599.DOI: 10.1111/jse.12299

• Research Article • Previous Articles     Next Articles

Historical biogeography of Melicope (Rutaceae) and its close relatives with a special emphasis on Pacific dispersals

Marc S. Appelhans1,2*, Jun Wen2, Marco Duretto3, Darren Crayn4, and Warren L. Wagner2   

  1. 1Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute of Plant Sciences, University of Goettingen, Untere Karspuele 2, 37073 Goettingen, Germany
    2Department of Botany, National Museum of Natural History, Smithsonian Institution, PO Box 37012, Washington, DC 20013-7012, USA
    3National Herbarium of New South Wales, Royal Botanic Gardens & Domain Trust, Mrs Macquaries Rd, Sydney NSW 2000, Australia
    4Australian Tropical Herbarium, James Cook University, PO Box 6811, Cairns QLD 4870, Australia
  • Received:2017-10-17 Accepted:2017-12-22 Published:2018-12-13

Abstract: The genus Melicope (Rutaceae) occurs on most Pacific archipelagos and is perfectly suited to study Pacific biogeography. The main goal was to infer the age, geographic origin and colonization patterns of Melicope and its relatives. We sequenced three nuclear and two plastid markers for 332 specimens that represent 164 species in 16 genera of Rutaceae. Phylogenetic reconstruction, molecular dating, ancestral area reconstruction and diversification analyses were carried out. The two main clades (Acronychia‐Melicope and Euodia) originated in Australasia and their crown ages are dated to the Miocene. Diversification rates differed among the subclades and were lowest in the Euodia lineage and highest in the Hawaiian Melicope lineage. The Malagasy and Mascarene species form a clade, which split from its SE Asian relatives in the Pliocene/Pleistocene. At least eight colonizations to the Pacific islands occurred. The timing of all colonizations except for the Hawaiian group is congruent with age of the island ages. Australia, New Guinea and New Caledonia have been the source of colonizations into the Pacific islands in the Melicope clade. Melicope shows high dispersability and has colonized remote archipelagos such as the Austral and Marquesas Islands each twice. Colonization of islands of the Hawaiian‐Emperor seamount chain likely predates the ages of the current main islands, and the initial colonization to Kaua'i occurred after the splitting of the Hawaiian lineage into two subclades. Wider ecological niches and adaptations to bird‐dispersal likely account for the much higher species richness in the Acronychia‐Melicope clade compared to the Euodia clade.

Key words: Acronychia, dispersal, Euodia, Melicope, Pacific biogeography, Rutaceae