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- Gautier, Laurent, et al.
(författare)
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A new species, genus and tribe of Sapotaceae, endemic to Madagascar
- 2013
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Ingår i: Taxon. - 0040-0262 .- 1996-8175. ; 62, s. 972-983
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Tidskriftsartikel (refereegranskat)abstract
- Phylogenetic relationships of the two Malagasy Sapotaceae endemic genera Capurodendron and Tsebona have been unclear until now. Recent collections from Madagascar, as well as a better representation of the tribe Isonandreae, altogether 95 terminals, were used to estimate a phylogeny of subfamily Sapotoideae. We analysed sequences of nrDNA (ITS) and cpDNA (trnH-psbA) with Bayesian inference and parsimony jackknifing. As in previous analyses, Sapoteae and Sideroxyleae are recovered monophyletic. In addition, Isonandreae, distributed in the Indo-Pacific, is for the first time resolved as monophy- letic and sister to Sapoteae. All Malagasy accessions of Capurodendron, Tsebona, and a new species are grouped in another well-supported clade. This clade is accommodated in a new tribe Tseboneae characterized by caducous stipules, 5-merous flowers with quincuncial sepals, contorted aestivation of corolla lobes, absence of corolla appendages, one or three stamens opposite each corolla lobe, villous staminodes, seeds with an adaxial scar and plano-convex cotyledons, lacking endosperm. The new species is described in the new genus Bemangidia (B. lowryi) because it has a unique leaf venation for the tribe and combines different morphological features from Capurodendron and Tsebona. All three genera are well-supported monophy- letic groups. Bemangidia lowryi is threatened with extinction due to extensive ongoing forest destruction and is assigned a preliminary conservation status of Critically Endangered.
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| 2. |
- Naciri, Yamama, et al.
(författare)
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A phylogenetic circumscription of Silene sect. Siphonomorpha (Caryophyllaceae) in the Mediterranean basin
- 2017
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Ingår i: Taxon. - : Wiley. - 0040-0262 .- 1996-8175. ; 66:1, s. 91-108
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Tidskriftsartikel (refereegranskat)abstract
- © International Association for Plant Taxonomy (IAPT) 2017. Silene sect. Siphonomorpha (Caryophyllaceae) has historically either been split into three different and homogeneous entities (sect. Italicae, sect. Paradoxae, sect. Siphonomorpha s.str.) or considered as a single group (sect. Siphonomorpha s.l.). In this study, we investigate the delimitation of sect. Siphonomorpha s.l. and the three subgroups, in order to sort out previous taxonomic concepts. We first performed an analysis of nuclear ribosomal internal transcribed spacer (ITS) sequences with wide taxonomic sampling to place sect. Siphonomorpha within the genus. Then, using nuclear and chloroplast sequences in a multi-species coalescent context, we constructed two species trees with independent specimen sampling. One was based on ITS, the nuclear RPA2 gene, and the plastid rps16 gene, the other used ITS and the plastid trnH-psbA and trnS-trnG regions. The results are congruent among the three analyses and show that sect. Siphonomorpha s.l. is not supported as being monophyletic and that an extended concept of this section would include species also belonging to sections Saxifragoideae, Coronatae, Tataricae, Chloranthae, Barbeyanae, Nanosilene, Otites, Koreanae, Brachypodae, Graminiformes, Dianthoidea, Longitubulosae and Holopetalae. However, the three entities “Italicae”, “Paradoxae” and “Siphonomorpha s.str.” are monophyletic with minor alterations and deserve taxonomic recognition as sections. Several ambiguous species are now resolved, among them the position of S. gigantea which is shown to be a highly supported clade, sister of sect. Italicae, that could therefore be named sect. Giganteae.
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| 3. |
- Naciri, Yamama, et al.
(författare)
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Convergent Morphological Evolution in Silene Sect. Italicae (Caryophyllaceae) in the Mediterranean Basin
- 2022
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Ingår i: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Recent divergence can obscure species boundaries among closely related taxa. Silene section Italicae (Caryophyllaceae) has been taxonomically controversial, with about 30 species described. We investigate species delimitation within this section using 500 specimens sequenced for one nuclear and two plastid markers. Despite the use of a small number of genes, the large number of sequenced samples allowed confident delimitation of 50% of the species. The delimitation of other species (e.g., Silene nemoralis, S. nodulosa and S. andryalifolia) was more challenging. We confirmed that seven of the ten chasmophyte species in the section are not related to each other but are, instead, genetically closer to geographically nearby species belonging to Italicae yet growing in open habitats. Adaptation to chasmophytic habitats therefore appears to have occurred independently, as a result of convergent evolution within the group. Species from the Western Mediterranean Basin showed more conflicting species boundaries than species from the Eastern Mediterranean Basin, where there are fewer but better-delimited species. Significant positive correlations were found between an estimation of the effective population size of the taxa and their extent of occurrence (EOO) or area of occupancy (AOO), and negative but non-significant correlations between the former and the posterior probability (PP) of the corresponding clades. These correlations might suggest a lower impact of incomplete lineage sorting in species with low effective population sizes and small distributional ranges compared with that in species inhabiting large areas. Finally, we confirmed that S. italica and S. nemoralis are distinct species, that S. nemoralis might furthermore include two different species and that S. velutina from Corsica and S. hicesiae from the Lipari Islands are sister species.
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