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Küpfer, Philippe

Nom
Küpfer, Philippe
Affiliation principale
Fonction
Professeur honoraire
Email
philippe.kuepfer@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/301

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  • Publication
    Accès libre
    Phylogenetics of tribe Exaceae (Gentianaceae) based on molecular, morphological and karyological data, with special emphasis on the genus Sebaea.: Taxonomic treatment of Exochaenium, Lagenias and the new genus Klackenbergia
    (2007)
    Kissling, Jonathan 
    ;
    Küpfer, Philippe 
    ;
    Linder, Peter
    In an attempt to understand the evolutionary history of the poorly studied genus Sebaea and its relationship to other genera of tribe Exaceae (Gentianaceae), intensive morphological and karyological character optimization based on robust molecular phylogeny was performed. Phylogenetic reconstructions support the monophyly of Exaceae, and further reveal a polyphyletic Sebaea, including four well-supported clades, hereafter treated as separate genera, based on non-molecular synapomorphies. The first clade contains the single species Lagenias pusillus, characterized by its medifix anthers, inserted at the base of the corolla tube and its seed testa cells (polygonal). The second clade, Sebaea s. str., contains most of the South African species having secondary stigmas and bilateral seeds, with rectangular testa cell. The third clade, Exochaenium, contains exclusively tropical African species, characterized by a stylar polymorphism and a papillose clavate stigma (versus smooth and bilobed). Finally the fourth clade, Klackenbergia, contains two species characterized by inflorescences with axillary subsessile flowers. Based on these results, the taxonomic reinstatement of Exochaenium (23 species) and Lagenias (1 species), along with the establishment of a new genus Klackenbergia (2 species), are proposed. In the light of the new phylogenetic relationships found within the Exaceae, new views on the evolution of (1) karyological and (2) morphological characters are proposed. Finally, the historical biogeography of the tribe is reevaluated (3). 1. Intensive chromosome counts based on material collected and fixed in the field (157 population and c. 60 species), and exhaustive literature survey, reveal a broad set of chromosome numbers (2n = 18, 28, 32, 34, 36, 42, 52, 54, 56, 60, 62, 64, 68), and the occurrence of polyploid systems within Exacum and Sebaea. These results allow us to postulate x = 7, 8, or 9 as the possible base chromosome numbers for the Exaceae. Karyological reconstruction, based on the molecular phylogeny, suggest a basic number of x=7 for the Exaceae, followed by dysploidy event leading to secondary base number of x=8 and x=9, and several polyploidization events. 2. Optimization of morphological characters suggests that the most recent common ancestor of Exaceae (MRCA) was similar to Lagenias pusillus by having pentamerous yellow actinomorphic flowers, with anthers included in the corolla tube and dehiscing by longitudinal slits, a bilobed stigma, and the absence of secondary stigmas, and cubical seeds with polygonal testa cells. This MRCA might have then developed particular floral syndromes as indicated by long corolla tubes or presence of enantiostyly in the tribe. 3. Dating analyses and dispersal-vicariance reconstructions suggest that the Exaceae evolved c. 32 million years ago in Africa and subsequently spread to Madagascar. The colonization of Australia, New-Zealand, and Asia involved at least three long-distance dispersals. Early diversification of Exaceae in Africa might be the consequence of the development of a temperate with dry summer climate, in the Cape region (South Africa), while the Quaternary climatic variation might explain most of the species diversity of Sebaea and Exochaenium. At the generic level, molecular phylogenies of Sebaea, based on chloroplastic and nuclear DNA markers, reveals five well-supported clades. Sebaea sulphurea seems to have evolved early, and is distinct from all the remaining extant species. Each clade is supported by several characters (morphological, vegetative, phenological or geographical), and a preliminary infrageneric classification is proposed.
  • Publication
    Accès libre
    Phylogeny and Biogeography of Exacum (Gentianaceae): A Disjunctive Distribution in the Indian Ocean Basin Resulted from Long Distance Dispersal and Extensive Radiation
    (2005)
    Yuan, Yong-Ming
    ;
    Wohlhauser, Sébastien
    ;
    Möller, Michael
    ;
    Klackenberg, Jens
    ;
    Callmander, Martin W.
    ;
    Küpfer, Philippe 
    Disjunctive distributions across paleotropical regions in the Indian Ocean Basin (IOB) often invoke dispersal/vicariance debates. Exacum (Gentianaceae, tribe Exaceae) species are spread around the IOB, in Africa, Madagascar, Socotra, the Arabian peninsula, Sri Lanka, India, the Himalayas, mainland Southeast Asia including southern China and Malaysia, and northern Australia. The distribution of this genus was suggested to be a typical example of vicariance resulting from the breakup of the Gondwanan supercontinent. The molecular phylogeny of Exacum is in principle congruent with morphological conclusions and shows a pattern that resembles a vicariance scenario with rapid divergence among lineages, but our molecular dating analysis demonstrates that the radiation is too recent to be associated with the Gondwanan continental breakup. We used our dating analysis to test the results of DIVA and found that the program predicted impossible vicariance events. Ancestral area reconstruction suggests that Exacum originated in Madagascar, and divergence dating suggests its origin was not before the Eocene. The Madagascan progenitor, the most recent common ancestor of Exacum, colonized Sri Lanka and southern India via long-distance dispersals. This colonizer underwent an extensive range expansion and spread to Socotra-Arabia, northern India, and mainland Southeast Asia in the northern IOB when it was warm and humid in these regions. This widespread common ancestor retreated subsequently from most parts of these regions and survived in isolation in Socotra-Arabia, southern India–Sri Lanka, and perhaps mainland Southeast Asia, possibly as a consequence of drastic climatic changes, particularly the spreading drought during the Neogene. Secondary diversification from these surviving centers and Madagascar resulted in the extant main lineages of the genus. The vicariance-like pattern shown by the phylogeny appears to have resulted from long-distance dispersals followed by extensive range expansion and subsequent fragmentation. The extant African species E. oldenlandioides is confirmed to be recently dispersed from Madagascar.
  • Publication
    Métadonnées seulement
    Phylogeny and biogeography of Exacum (Gentianaceae): A disjunctive distribution in the Indian Ocean Basin resulted from long distance dispersal and extensive radiation
    (2005)
    Yuan, Yong-Ming
    ;
    Wohlhauser, Sébastien
    ;
    Moller, Michael
    ;
    Klackenberg, Jens
    ;
    Callmander, Martin
    ;
    Küpfer, Philippe 
    Disjunctive distributions across paleotropical regions in the Indian Ocean Basin (IOB) often invoke dispersal/vicariance debates. Exacum (Gentianaceae, tribe Exaceae) species are spread around the IOB, in Africa, Madagascar, Socotra, the Arabian peninsula, Sri Lanka, India, the Himalayas, mainland Southeast Asia including southern China and Malaysia, and northern Australia. The distribution of this genus was suggested to be a typical example of vicariance resulting from the breakup of the Gondwanan supercontinent. The molecular phylogeny of Exacion is in principle congruent with morphological conclusions and shows a pattern that resembles a vicariance scenario with rapid divergence among lineages, but our molecular dating analysis demonstrates that the radiation is too recent to be associated with the Gondwanan continental breakup. We used our dating analysis to test the results of DIVA and found that the program predicted impossible vicariance events. Ancestral area reconstruction suggests that Exacum originated in Madagascar, and divergence dating suggests its origin was not before the Eocene. The Madagascan progenitor, the most recent common ancestor of Exacion, colonized Sri Lanka and southern India via long-distance dispersals. This colonizer underwent an extensive range expansion and spread to Socotra-Arabia, northern India, and mainland Southeast Asia in the northern IOB when it was warm and humid in these regions. This widespread common ancestor retreated subsequently from most parts of these regions and survived in isolation in Socotra-Arabia, southern India-Sri Lanka, and perhaps mainland Southeast Asia, possibly as a consequence of drastic climatic changes, particularly the spreading drought during the Neogene. Secondary diversification from these surviving centers and Madagascar resulted in the extant main lineages of the genus. The vicariance-like pattern shown by the phylogeny appears to have resulted from long-distance dispersals followed by extensive range expansion and subsequent fragmentation. The extant African species E. oldenlandioides is confirmed to be recently dispersed from Madagascar.
  • Publication
    Accès libre
    High paraphyly of Swertia L. (Gentianaceae) in the Gentianella -lineage as revealed by nuclear and chloroplast DNA sequence variation
    (2001)
    Chassot, P.
    ;
    Nemomissa, S.
    ;
    Yuan, Yong-Ming
    ;
    Küpfer, Philippe 
    The genus Swertia L., as currently defined, is polymorphic and mainly distributed in temperate regions of the northern hemisphere. Phylogenetic relationships between Swertia and the other genera of the Swertiinae sensu Struwe et al. (unpubl. data) are discussed based on cladistic analyses of DNA sequence data. The sequences used for this purpose include the trnL (UAA) intron, the intergenic spacers (IGS) between trnL (UAA) and trnF (GAA) exons, and between trnS (UGA) and ycf 9 exons of cpDNA, as well as the ITS region of nrDNA. Although moderately resolved, the phylogenies resulting from the separate analyses of nuclear and chloroplast data are congruent, and the incongruence length difference test (Farris et al. 1995) detected no character incongruence. The phylogeny suggested by the analysis of combined data sets defines Swertia as strongly paraphyletic in relation to the other genera. This taxon may have acted as a stem group, giving rise to diverse lineages, some of which are morphologically distinct and have been recognised at the generic level. Latouchea and Obolaria are closely related and occupy the basalmost position in the molecular tree. Swertia species are distributed in 9 different clades, three of which share a basal polytomy with Bartonia, Frasera, Gentianopsis, Halenia, Megacodon, Pterygocalyx and Veratrilla. Two lineages have an intermediate position. The remaining 4 clades occupy a more derived position. Two of the latter clades show a close relation with species of Gentianella s. str., and one is included in a large clade comprising Comastoma, Jaeschkea and Lomatogonium. Selected character states and their proposed polarity, such as number and structure of nectaries, stylar and seedcoat characteristics, pollen morphology, fusion of floral parts and chromosome number are discussed in the context of molecular data. Rugose, spinose, or winged seeds are found mainly in basal lineages, while smooth ones are typical for derived species. Chromosome numbers follow a similar pattern with x=13 restricted to basal lineages, while in more derived clades, x is always smaller than 13. With respect to the molecular phylogeny, taxonomic circumscriptions in the Swertiinae sensu Struwe et al. (unpubl. data) does not seem to reflect phyletic relationships.
  • Publication
    Accès libre
    Cytotaxonomic notes on the tribe Helieae (Gentianaceae)
    Trunz, Vincent
    ;
    Zeltner, Louis
    ;
    Küpfer, Philippe 
    ;
    Grant, Jason 
    A survey of all known chromosome counts of gentian tribe Helieae are presented including new reports for ten species. Amongst the novelties are four genera of the Gentianaceae that are reported for the first time, Calolisianthus and Helia (both Helieae), and Schultesia and Zygostigma (both Chironieae). In the Helieae, our results reinforce the hypothesis of Weaver 1969 that two ploidy series occur in the tribe, one polyploid based on n = 20 and one dysploid based on n = 21. The basal chromosome number for the Helieae remains to be determined.