Molecular systematics and evolutionary trends and relationships in the genus Jumellea (Orchidaceae): Implications for its species limits

Abstract : \textlessI\textgreaterJumellea\textless/I\textgreater is an orchid genus centered on Madagascar but also occurs on some of the neighboring oceanic islands (the Mascarenes and Comoros) and in southern and eastern Africa. Prior to our study the genus contained ca. 55 morphologically distinct species, of which six are found in the Comoros (three endemic, three shared with Madagascar), nine in the Mascarenes (four endemic, four shared with Madagascar), two in southern and eastern Africa (both endemic), and 41 species endemic to Madagascar. We perform Bayesian and parsimony phylogenetic analyses of \textlessI\textgreaterJumellea\textless/I\textgreater based on combined chloroplast (\textlessI\textgreatermatK\textless/I\textgreater, \textlessI\textgreatertrnL-F\textless/I\textgreater, \textlessI\textgreaterrps16\textless/I\textgreater, \textlessI\textgreaterycf1\textless/I\textgreater) and nuclear (nrITS) data from 60 specimens representing 47 species, four subspecies, and two varieties of \textlessI\textgreaterJumellea\textless/I\textgreater: (1) to assess the phylogenetic value of growth form, leaf, bract and lip shape, and spur length, presently used for recognizing informal groups within the genus; and (2) to test the monophyly of some variable species (e.g., \textlessI\textgreaterJ. gracilipes\textless/I\textgreater, \textlessI\textgreaterJ. lignosa\textless/I\textgreater). We find no support for the informal groups of \textlessI\textgreaterJumellea\textless/I\textgreater, as all the characters tested are evolutionarily labile. \textlessI\textgreaterJumellea lignosa\textless/I\textgreater (comprising \textlessI\textgreaterJ. lignosa\textless/I\textgreater subsp. \textlessI\textgreaterlignosa\textless/I\textgreater, subsp. \textlessI\textgreatertenuibracteata\textless/I\textgreater, subsp. \textlessI\textgreateracutissima\textless/I\textgreater, and subsp. \textlessI\textgreaterlatilabia\textless/I\textgreater) is not monophyletic unless subsp. \textlessI\textgreatertenuibracteata\textless/I\textgreater is excluded. \textlessI\textgreaterJumellea gracilipes\textless/I\textgreater s. l. (including \textlessI\textgreaterJ. ambongensis\textless/I\textgreater, \textlessI\textgreaterJ. imerinensis\textless/I\textgreater, and \textlessI\textgreaterJ. unguicularis\textless/I\textgreater) is polyphyletic. As a result, we resurrect these three latter species, and recognize \textlessI\textgreaterJ. lignosa\textless/I\textgreater subsp. \textlessI\textgreatertenuibracteata\textless/I\textgreater at species level. Furthermore, we propose new circumscriptions for the following species: the Comorian \textlessI\textgreaterJ. arachnantha\textless/I\textgreater (including the Malagasy \textlessI\textgreaterJ. sagittata\textless/I\textgreater); the Reunionese \textlessI\textgreaterJ. exilis\textless/I\textgreater (including the Malagasy \textlessI\textgreaterJ. flavescens\textless/I\textgreater); the Reunionese \textlessI\textgreaterJ. recta\textless/I\textgreater (including the Malagasy \textlessI\textgreaterJumellea\textless/I\textgreater sp. 1); the Reunionese \textlessI\textgreaterJ. recurva\textless/I\textgreater (including the Malagasy \textlessI\textgreaterJ. pandurata\textless/I\textgreater); and the Reunionese \textlessI\textgreaterJ. stenophylla\textless/I\textgreater (including the Malagasy \textlessI\textgreaterJ. gracilipes\textless/I\textgreater 2 and 3). Finally, \textlessI\textgreaterJumellea arborescens\textless/I\textgreater and \textlessI\textgreaterJ. maxillarioides\textless/I\textgreater are recorded from Madagascar and the Comoros. Finally, the number of species of \textlessI\textgreaterJumellea\textless/I\textgreater has now increased from 55 to 57: seven species in the Comoros (four shared with Madagascar), nine species in the Mascarenes (four shared with Madagascar), two species in Africa, and 39 species, three subspecies, and two varieties restricted to Madagascar.
Type de document :
Article dans une revue
Taxon, Botanischer Garten und Botanisches Museum, 2012, 61 (3), pp.534--544
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Soumis le : mardi 15 septembre 2015 - 12:01:41
Dernière modification le : vendredi 14 septembre 2018 - 08:16:38

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Fanny P. Rakotoarivelo, Sylvain G. Razafimandimbison, Bertrand Mallet, Lucien Faliniaina, Thierry Pailler. Molecular systematics and evolutionary trends and relationships in the genus Jumellea (Orchidaceae): Implications for its species limits. Taxon, Botanischer Garten und Botanisches Museum, 2012, 61 (3), pp.534--544. 〈hal-01199329〉

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