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- Banag, Cecilia I., et al.
(författare)
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Ixora (Rubiaceae) on the Philippines - crossroad or cradle?
- 2017
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Ingår i: BMC Evolutionary Biology. - : Springer Science and Business Media LLC. - 1471-2148. ; 17
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Tidskriftsartikel (refereegranskat)abstract
- Background: The Philippine archipelago is globally one of the most important model island systems for studying evolutionary processes. However, most plant species on this archipelago have not yet been studied in sufficient detail. The main aim of this study is to unravel the evolutionary history and biogeographic relationships of the Philippine members of the pantropical genus Ixora. Results: The complex plastid and nuclear divergence patterns in Philippine Ixora, documented using tree and network approaches, reveal a highly dynamic evolution in Ixora, involving several phases of radiation and recolonization. Philippine Ixora comprises at least five lineages, of which one is most closely related to species from Wallacea, and the remaining four to species from Asia. Conclusions: Our study highlights the importance of Philippine species for understanding phytogeographic patterns in the Indomalayan-Australasian eco-region. The overall genetic differentiation, as well as the incongruence between genealogies based on the biparentally inherited nucleome and the maternally inherited plastome in Ixora, reflect the complex tectonic history of the Philippine archipelago. The Ixora lineage related to Wallacean species supports the delimitation of different ecozones along Huxley's line, because it is absent from Palawan. The remaining four lineages are all allied with Asian taxa, reflecting several waves of colonization. Close relationships between some widespread Philippine species and locally adapted narrow endemics suggest that the widespread, genetically diverse species act as pools for the formation of new species in a process of ongoing speciation. Our results suggest that the species concepts of some of the more widespread taxa need to be revised.
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| 4. |
- Ollerton, Jeff, et al.
(författare)
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Diversity of Diptera families that pollinate Ceropegia (Apocynaceae) trap flowers: An update in light of new data and phylogenetic analyses
- 2017
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Ingår i: Flora. - : Elsevier BV. - 0367-2530 .- 1618-0585. ; 234, s. 233-244
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Tidskriftsartikel (refereegranskat)abstract
- Pollination by flies (Diptera) has been important to the diversification and ecology of the flowering plants, but is poorly understood in contrast to pollination by other groups such as bees, butterflies and birds. Within the Apocynaceae the genera Ceropegia and Riocreuxia temporarily trap flies, releasing them after a fixed, species-specific period of time, during which pollination and/or pollen removal occurs. This "trap flower" pollination system shows convergent evolution with unrelated species in other families and fascinated Stefan Vogel for much of his career, leading to ground-breaking work on floral function in Ceropegia (Apocynaceae). In this new study we extend the work of the latest broad analysis published by some of the authors (Ollerton et al., 2009 − Annals of Botany). This incorporates previously unpublished data from India and Africa, as well as recently published information, on the diversity of pollinators exploited by Ceropegia. The analyses are based on a more accurate phylogenetic understanding of the relationships between the major groups, and significantly widens the biogeographic scope of our understanding of fly pollination within Ceropegia. Information about the pollinators of 69 taxa (species, subspecies and natural varieties) of Ceropegia is now available. Twenty five families of Diptera are known to visit the flowers of Ceropegia, of which sixteen are confirmed as pollinators. Most taxa are pollinated by species from a single family. Overall, there were no major biogeographic differences in the types of Diptera that were used in particular regions, though some subtle differences were apparent. Likewise there were no differences between the two major clades of Ceropegia, but clear differences when comparing the range of Diptera exploited by Ceropegia with that of the stapeliads. This clade, one of the largest in the Asclepiadoideae, is a fascinating example of a species radiation driven by an apparently relatively uniform set of pollinators.
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- Smedmark, Jenny E. E., et al.
(författare)
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A Phylogeny of Urophylleae (Rubiaceae) based on rps16 intron data
- 2008
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Ingår i: Taxon. - 0040-0262. ; 57:1, s. 24-32
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Tidskriftsartikel (refereegranskat)abstract
- This is the first study of phylogenetic relationships within the pantropical group Urophylleae. Previous studies have included few representatives from this group and little is known about its phylogeny. Here we use sequence data from the rps16 intron to address the question of where the four genera Temnopteryx, Pentaloncha, Pleiocarpidia, and Poecilocalyx, which have sometimes been classified in this group belong. By using different outgroups we show that there is conflict regarding the resolution among lineages in Rubioideae, which partly affects the support for relationships within Urophylleae. Urophylleae is shown to consist of two sister groups, one larger consisting only of Old World taxa and one smaller including the New World genera Amphidasya and Raritebe, and as sister of these two groups the African monotypic genus Temnopteryx. Pentaloncha, Pleiocarpidia, and Poecilocalyx all belong in the large Old World clade, which only comprises taxa included in the original circumscription of Urophylleae. Relationships within this group are not completely resolved, but Poecilocalyx is found to be the sister of Stelechantha and Pleiocarpidia to be the sister of Urophyllum leucophleum. Urophyllum is paraphyletic, as it seems to include Maschalocorymbus, Pleiocarpidia, Praravinia, and Pravinaria. It is not clear from the present analysis whether Pauridiantha is monophyletic or not.
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| 6. |
- Thulin, Mats, 1948-, et al.
(författare)
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Cibirhiza spiculata (Apocynaceae), a remarkable new species from eastern Ethiopia
- 2009
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Ingår i: Kew bulletin. - : Springer Science and Business Media LLC. - 0075-5974 .- 1874-933X. ; 63:4, s. 617-624
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Tidskriftsartikel (refereegranskat)abstract
- The new species Cibirhiza spiculata Thulin & Goyder, from Acacia-Commiphora bushland on sand in the Somali National Regional State (Ogaden) of Ethiopia, is described and illustrated. Its conservation status has been assessed. A molecular phylogenetic analysis confirms its placement in the tribe Fockeeae and indicates a position of the new species as sister to C. albersiana. The almost obsolete anther appendages, the outer corona with spreading lobes, as well as the pollinia with apparently single pollen grains, also support its placement in Cibirhiza. However, C. spiculata differs markedly from both previously known species of this genus (C. dhofarensis in Oman and Yemen and C. albersiana in Tanzania and Zambia) by its narrowly linear, subsessile leaves and by the inner corona lobes that are curved inwards over the gynostegium and each ending in a spinulose head.
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| 7. |
- Thulin, Mats, et al.
(författare)
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Phylogeny and taxonomy of Tribulocarpus (Aizoaceae) : A paraphyletic species and an adaptive shift from zoochorous trample burrs to anemochorous nuts
- 2012
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Ingår i: Taxon. - 0040-0262 .- 1996-8175. ; 61:1, s. 55-66
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Tidskriftsartikel (refereegranskat)abstract
- The phylogenetic position and circumscription of the disjunct African genus Tribulocarpus is investigated with DNA sequences from plastid rps16 and trnL-F, and nuclear ITS. Representatives from all four subfamilies of Aizoaceae are included in the analyses, most of them from Aizooideae and Sesuvioideae. The position of Tribulocarpus as sister to the rest of Sesuvioideae is confirmed, and we agree that the genus should be referred to this subfamily. Tetragonia retusa is found to be part of the Tribulocarpus clade with strong support. A new taxonomy of Tribulocarpus with two species is proposed and the new combination Tribulocarpus retusus is made. A lectotype is designated for Tetragonia somalensis. Tribulocarpus dimorphanthus, disjunctly distributed in south-western and north-eastern Africa, is retrieved as paraphyletic with regard to T. retusus, endemic in Somalia, as the latter is sister to the north-east African part of T. dimorphanthus only. Despite the genetic difference between the samples from the disjunct populations of T. dimorphanthus no morphological differences could be detected. Tribulocarpus dimorphanthus-T. retusus is suggested as an example of a progenitor-derivative species pair, where T. retusus has budded off from the north-eastern partial area of distribution of T. dimorphanthus. The compound and spiny fruits of T. dimorphanthus versus the simple and broadly winged fruits of T. retusus indicate a rapid adaptive shift from zoochorous trample burrs to anemochorous nuts.
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