J Syst Evol ›› 2021, Vol. 59 ›› Issue (5): 1000-1017.DOI: 10.1111/jse.12581

• Research Articles • Previous Articles     Next Articles

Weda, a new genus with two new species of Euphorbiaceae-Crotonoideae from Halmahera (North Maluku, Indonesia) and phylogenetic relationships of the Australasian tribe Ricinocarpeae

Peter C. van Welzen1,2*, Susana Arias Guerrero1, Deby Arifiani3, Tjut J.F. Bangun4, Roderick W. Bouman1,2,5, Marcel C.M. Eurlings1, Iska Gushilman6, Peter B. Phillipson7,8, Iris Tabak1, Esmée Winkel1, and Kenneth J. Wurdack9   

  1. 1 Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA, Leiden, The Netherlands
    2 Institute of Biology Leiden, Leiden University, P.O. Box 9505, 2300 RA, Leiden, The Netherlands
    3 Herbarium Bogoriense, Botany Division, Research Center for Biology, Indonesian Institute of Sciences, Cibinong, Bogor, Indonesia
    4 North Gorua Village, RT 006/RW 03, North Tobelo District, North Halmahera, North Maluku, Indonesia
    5 Hortus botanicus, Leiden University, 2311 GJ, Leiden, The Netherlands
    6 Bumi Mekar Wangi Residence, Blok C6 No. 12, RT 04/RW 05, Tanah Sereal, Bogor 16168, Indonesia
    7 Missouri Botanical Garden, St. Louis, MO 63110, USA
    8 Institut de Systématique, Évolution, et Biodiversité (ISYEB), Muséum National d'Histoire Naturelle, Centre National de la Recherche Scientifique, Sorbonne Université, École Pratique des Hautes Études, Université des Antilles, C.P. 39, 57 rue Cuvier, Paris 75005, France
    9 Department of Botany, MRC‐166, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013‐7012, USA
  • Received:2020-01-17 Accepted:2020-03-04 Online:2020-03-06 Published:2021-09-01

Abstract: During the environmental impact study for a proposed nickel mine near Weda Bay on Halmahera in North Moluccas (Maluku Utara Province), Indonesia, two unknown Euphorbiaceae were discovered. Morphological comparisons and molecular phylogenetic analyses using four markers (plastid trnL-F and rbcL, and nuclear ribosomal internal transcribed spacer and external transcribed spacer) indicated that they should be recognized as constituting a new, distinct genus of two species, which are described and illustrated here as Weda fragarioides and Weda lutea. The new taxa are members of the Australasian tribe Ricinocarpeae in subfamily Crotonoideae, and they are most closely related to Alphandia. In contrast with the otherwise mostly sclerophyllous Ricinocarpeae, Weda possesses stellate to dendritic hairs, large, long-petiolate, glandular leaves, and inflorescences with a pair of large, leafy, subopposite bracts. The two narrowly distributed species are distinguished from each other by vegetative and floral features, molecular data, and elevational preferences. Leaf elemental analysis of Weda indicated manganese, but not nickel, accumulation. Newly resolved generic relationships and potential morphological synapomorphies within Crotonoideae are discussed, and the circumscription of Ricinocarpeae is expanded from 7 to 11 genera.

Key words: Crotonoideae, elemental analysis, Euphorbiaceae, Malesia, molecular phylogenetics, Ricinocarpeae