Delimitation of the genus Margaritopsis (Rubiaceae) in the Asian, Australasian and Pacific region, based on molecular phylogenetic inference and morphology

Barrabé Laure, Buerki Sven, Mouly Arnaud, Davis Aaron P., Munzinger Jérôme, Maggia Laurent. 2012. Delimitation of the genus Margaritopsis (Rubiaceae) in the Asian, Australasian and Pacific region, based on molecular phylogenetic inference and morphology. Taxon, 61 (6) : pp. 1251-1268.

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Quartile : Q1, Sujet : PLANT SCIENCES / Quartile : Q2, Sujet : EVOLUTIONARY BIOLOGY

Abstract : In the past, the circumscription of the large genus Psychotria (Rubiaceae) was difficult, until molecular phylogenetic studies revealed its considerable paraphyly, enabling the delimitation of its major lineages and the grouping of related genera, and most notably the separation of Psychotria and its relatives (former Psychotrieae) into two tribes: Psychotrieae and Palicoureeae. The genus Margaritopsis, which is included in Palicoureeae, encompasses 27 Neotropical species, and in previous studies these have been shown to be close relatives of a group of eight Psychotria species that occur over a large region extending from South-East Asia to tropical South Pacific through Malesia (= the AMP region, defined as including South-East Asia, Malesia, tropical Australia, Melanesia, Micronesia, New Caledonia and Polynesia). A molecular phylogenetic study, using one nuclear DNA region (ITS) and four plastid DNA regions (ndhF, rps16, trnH-psbA, trnT-F), is undertaken in order to test the placement of 17 AMP Psychotria species within Palicoureeae. The phylogenetic results show that they form a monophyletic clade (= clade G), which also includes the monotypic Fijian genus Readea and Hodgkinsonia frutescens from Australia. Clade G is embedded in a well-supported grade with five Neotropical representatives of Margaritopsis. A morphological survey based on twenty characters, with the potential to circumscribe generic entities, shows that the monophyly of clade G is supported by a character combination that is similar to species of Neotropical Margaritopsis, confirming their inclusion in this genus. Taxonomic and nomenclatural work on these species is required to formalize nomenclatural implications. Based on the same set of morphological characters, but in absence of molecular data, 28 other Psychotria species from the AMP region were detected as likely candidates for inclusion in Margaritopsis, allowing the estimation of species richness of clade G to be a minimum of 47 species. Within clade G, five well-supported subclades and a Readea lineage are delimited and each of these is generally supported by unique morphological features. Phylogenetic topologies reveal biogeographical patterns, including a main route of dispersal from western to eastern parts of the AMP region, with subsequent dispersals between archipelagos in the region. (Résumé d'auteur)

Mots-clés Agrovoc : Psychotria

Mots-clés géographiques Agrovoc : Asie, Asie et Pacifique, Australie

Mots-clés complémentaires : Margaritopsis

Classification Agris : F70 - Plant taxonomy and geography
F30 - Plant genetics and breeding

Champ stratégique Cirad : Axe 6 (2005-2013) - Agriculture, environnement, nature et sociétés

Auteurs et affiliations

  • Barrabé Laure, CIRAD-BIOS-UMR AGAP (NCL)
  • Buerki Sven, Royal Botanic Gardens (GBR)
  • Mouly Arnaud, Université de Franche-Comté (FRA)
  • Davis Aaron P., Royal Botanic Gardens (GBR)
  • Munzinger Jérôme, IRD (NCL)
  • Maggia Laurent, CIRAD-BIOS-UMR AGAP (NCL)

Source : Cirad - Agritrop (

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