Browsing by Author "Santos-Guerra, Arnoldo"
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- An expanded molecular phylogeny of Plumbaginaceae, with emphasis on Limonium (sea lavenders): taxonomic implications and biogeographic considerationsPublication . Koutroumpa, Konstantina; Theodoridis, Spyros; Warren, Ben H.; Jiménez, Ares; Celep, Ferhat; Doğan, Musa; Romeiras, Maria M.; Santos-Guerra, Arnoldo; Fernández-Palacios, José María; Caujapé-Castells, Juli; Moura, Mónica; Sequeira, Miguel Menezes de; Conti, ElenaPlumbaginaceae is characterized by a history of multiple taxonomic rearrangements and lacks a broad molecular phylogenetic framework. Limonium is the most species‐ rich genus of the family with ca. 600 species and cosmopolitan distribution. Its center of diversity is the Mediterranean region, where ca. 70% of all Limonium species are endemic. In this study, we sample 201 Limonium species covering all described infra‐ generic entities and spanning its wide geographic range, along with 64 species of other Plumbaginaceae genera, representing 23 out of 29 genera of the family. Additionally, 20 species of the sister family Polygonaceae were used as outgroup. Sequences of three chloroplast (trnL‐F, matK, and rbcL) and one nuclear (ITS) loci were used to infer the molecular phylogeny employing maximum likelihood and Bayesian analyses. According to our results, within Plumbaginoideae, Plumbago forms a non‐ monophyletic assemblage, with Plumbago europaea sister to Plumbagella, while the other Plumbago species form a clade sister to Dyerophytum. Within Limonioideae, Ikonnikovia is nested in Goniolimon, rejecting its former segregation as genus distinct from Goniolimon. Limonium is divided into two major clades: Limonium subg. Pteroclados s.l., including L. sect. Pteroclados and L. anthericoides, and L. subg. Limonium. The latter is divided into three well‐supported subclades: the monospecific L. sect. Limoniodendron sister to a clade comprising a mostly non‐Mediterranean subclade and a Mediterranean subclade. Our results set the foundation for taxonomic propos‐ als on sections and subsections of Limonium, namely: (a) the newly described L. sect. Tenuiramosum, created to assign L. anthericoides at the sectional rank; (b) the more restricted circumscriptions of L. sect. Limonium (= L. sect. Limonium subsect. Genuinae) and L. sect. Sarcophyllum (for the Sudano‐Zambezian/Saharo‐Arabian clade); (c) the more expanded circumscription of L. sect. Nephrophyllum (including species of the L. bellidifolium complex); and (d) the new combinations for L. sect. Pruinosum and L. sect. Pteroclados subsect. Odontolepideae and subsect. Nobiles.
- Breeding systems in Tolpis (Asteraceae) in the Macaronesian islands: the Azores, Madeira and the CanariesPublication . Crawford, Daniel J.; Anderson, Gregory J.; Silva, Lurdes Borges; Sequeira, Miguel Menezes de; Moura, Mónica; Santos-Guerra, Arnoldo; Kelly, John K.; Mort, Mark E.Plants on oceanic islands often originate from self-compatible (SC) colonizers capable of seed set by self fertilization. This fact is supported by empirical studies, and is rooted in the hypothesis that one (or few) individuals could find a sexual population, whereas two or more would be required if the colonizers were self-incompatible (SI). However, a SC colonizer would have lower heterozygosity than SI colonizers, which could limit radiation and diver sification of lineages following establishment. Limited evidence suggests that several species-rich island lineages in the family Asteraceae originated from SI colonizers with some ‘‘leakiness’’ (pseudo-self-compatibility, PSC) such that some self-seed could be produced. This study of Tolpis (Asteraceae) in Macaronesia provides first reports of the breeding system in species from the Azores and Madeira, and additional insights into variation in Canary Islands. Tolpis from the Azores and Madeira are predominately SI but with PSC. This study suggests that the breeding sys tems of the ancestors were either PSC, possibly from a single colonizer, or from SI colonizers by multiple dis seminules either from a single or multiple dispersals. Long distance colonists capable of PSC combine the advantages of reproductive assurance (via selfing) in the establishment of sexual populations from even a single colonizer with the higher heterozygosity resulting from its origin from an outcrossed source population. Evolution of Tolpis on the Canaries and Madeira has generated diversity in breeding systems, including the origin of SC. Macaronesian Tolpis is an excellent system for studying breeding system evolution in a small, diverse lineage.
- Karyological analysis of the five native Macaronesian Festuca (Gramineae) grasses supports a distinct diploid origin of two schizoendemic groupsPublication . Sequeira, Miguel Menezes de; Díaz-Pérez, Antonio; Santos-Guerra, Arnoldo; Viruel, Juan; Catalán, PilarMenezes de Sequeira, M., Díaz-Pérez, A., Santos-Guerra, A., Viruel, J. & Catalán, P. 2009. Karyological analysis of the five na tive Macaronesian Festuca (Gramineae) grasses supports a dis tinct diploid origin of two schizoendemic groups. Anales Jard. Bot. Madrid 66(1): 55-63. A karyological analysis has been conducted of all five native Macaronesian Festuca grasses belonging to fine-leaved F. subg. Festuca sect. Aulaxyper and broad-leaved F. subg. Drymanthele sect. Phaeochloa Loliinae lineages. Chromosomal analyses were made in 30 plants corresponding to 17 populations of the fine leaved F. agustinii, F. jubata, F. francoi and F. petraea and 2 pop ulations of the broad-leaved F. donax. All counts except one tetraploid count were diploids, showing 2n = 14 chromosomes. Diploidy was confirmed for the robust F. donax, nested within a clade of relict ancestral fescues as reported in recent phyloge netic studies, and was also found in the more slender F. agus tinii, F. jubata, F. francoi and F. petraea, which are basal to a re cently evolved clade of polyploid red fescues. Karyotypes of the two groups are however distinct, with broad-leaved F. donax showing larger and more regular chromosomes and all four fine-leaved taxa showing smaller and more irregular submeta centric chromosomes. Our karyological data indicate that these two groups of diploid fescues correspond to distinct schizoen demics which apparently originated at different times after in dependent continental colonizations of Macaronesia
- Multiple colonizations, in situ speciation, and volcanism-associated stepping-stone dispersals shaped the phylogeography of the Macaronesian red fescues (Festuca L., Gramineae)Publication . Díaz-Pérez, Antonio; Sequeira, Miguel; Santos-Guerra, Arnoldo; Catalán, PilarWhereas examples of insular speciation within the endemic-rich Macaronesian hotspot flora have been documented, the phylogeography of recently evolved plants in the region has received little attention. The Macaronesian red fescues constitute a narrow and recent radiation of four closely related diploid species distributed in the Canary Islands (F. agustinii), Madeira (F. jubata), and the Azores (F. francoi and F. petraea), with a single extant relative distributed in mainland southwest Europe (F. rivularis). Bayesian structure and priority consensus tree approaches and population spatial correla tions between genetic, geographical, and dispersal distances were used to elucidate the phylogeographical patterns of these grasses. Independent versus related origins and dispersal versus isolation by distance (IBD) hypotheses were tested to explain the genetic differentiation of species and populations, respectively. Genetic structure was found to be geographi cally distributed among the archipelagos and the islands endemics. The high number of shared AFLP fragments in all four species suggests a recent single origin from a continental Pliocene ancestor. However, the strong allelic structure detected among the Canarian, Madeiran, and Azorean endemics and the significant standardized residual values obtained from structured Bayesian analysis for pairwise related origin hypotheses strongly supported the existence of three independent continental-oceanic colonization events. The Canarian F. agustinii, the Madeiran F. jubata, and the two sister F. francoi and F. petraea Azorean species likely evolved from different continental founders in their respective archipelagos. Despite the short span of time elapsed since colonization, the two sympatric Azorean species probably diverged in situ, following eco logical adaptation, from a common ancestor that arrived from the near mainland. Simple dispersal hypotheses explained most of the genetic variation at the species level better than IBD models. The optimal dispersal model for F. agustinii was a bidirectional centripetal stepping-stone colonization pattern, an eastern-to-western volcanism-associated dispersion was fa vored for F. francoi, whereas for the recently derived F. petraea a counterintuitive direction of colonization (west-to-east) was suggested. The population-based phylogeographical trends deduced from our study could be used as predictive models for other Macaronesian plant endemics with similar distribution areas and dispersal abilities. [Bayesian genetic analyses; colonization of oceanic islands; dispersal models; Festuca sect. Aulaxyper; Macaronesia; phylogeography.]
- Multiplexed-shotgun-genotyping data resolve phylogeny within a very recently derived insular lineagePublication . Mort, Mark E.; Crawford, Daniel J.; Kelly, John K.; Santos-Guerra, Arnoldo; Sequeira, Miguel Menezes de; Moura, Mónica; Caujapé-Castells, JuliPremise of the study: Endemic plants on oceanic islands have long served as model systems for studying patterns and processes of evolution. However, phylogenetic studies of island plants frequently illustrate a decoupling of molecular divergence and ecological/morphological diversity, resulting in phylogenies lacking the resolution required to interpret patterns of evolution in a phylogenetic context. The current study uses the primarily Macaronesian fl owering plant genus Tolpis to illustrate the utility of multiplexed shotgun genotyping (MSG) for resolving relationships at relatively deep (among archipelagos) and very shallow (within archipelagos) nodes in this small, yet diverse insular plant lineage that had not been resolved with other molecular markers. • Methods: Genomic libraries for 27 accessions of Macaronesian Tolpis were generated for genotyping individuals using MSG, a form of reduced-representation sequencing, similar to restriction-site-associated DNA markers (RADseq). The resulting data fi les were processed using the program pyRAD, which clusters MSG loci within and between samples. Phylogenetic analyses of the aligned data matrix were conducted using RAxML. • Key results: Analysis of MSG data recovered a highly resolved phylogeny with generally strong support, including the fi rst robust inference of relationships within the highly diverse Canary Island clade of Tolpis . • Conclusions: The current study illustrates the utility of MSG data for resolving relationships in lineages that have undergone recent, rapid diversifi cation resulting in extensive ecological and morphological diversity. We suggest that a similar approach may prove generally useful for other rapid plant radiations where resolving phylogeny has been diffi cult.
- Systematics, biogeography, and character evolution of the legume tribe Fabeae with special focus on the middle-Atlantic island lineagesPublication . Schaefer, Hanno; Hechenleitner, Paulina; Santos-Guerra, Arnoldo; Sequeira, Miguel Menezes de; Pennington, R. Toby; Kenicer, Gregory; Carine, MarkBackground: Tribe Fabeae comprises about 380 legume species, including some of the most ancient and important crops like lentil, pea, and broad bean. Breeding efforts in legume crops rely on a detailed knowledge of closest wild relatives and geographic origin. Relationships within the tribe, however, are incompletely known and previous molecular results conflicted with the traditional morphology-based classification. Here we analyse the systematics, biogeography, and character evolution in the tribe based on plastid and nuclear DNA sequences. Results: Phylogenetic analyses including c. 70% of the species in the tribe show that the genera Vicia and Lathyrus in their current circumscription are not monophyletic: Pisum and Vavilovia are nested in Lathyrus, the genus Lens is nested in Vicia. A small, well-supported clade including Vicia hirsuta, V. sylvatica, and some Mediterranean endemics, is the sister group to all remaining species in the tribe. Fabeae originated in the East Mediterranean region in the Miocene (23–16 million years ago (Ma)) and spread at least 39 times into Eurasia, seven times to the Americas, twice to tropical Africa and four times to Macaronesia. Broad bean (V. faba) and its sister V. paucijuga originated in Asia and might be sister to V. oroboides. Lentil (Lens culinaris ssp. culinaris) is of Mediterranean origin and together with eight very close relatives forms a clade that is nested in the core Vicia, where it evolved c. 14 Ma. The Pisum clade is nested in Lathyrus in a grade with the Mediterranean L. gloeosperma, L. neurolobus, and L. nissolia. The extinct Azorean endemic V. dennesiana belongs in section Cracca and is nested among Mediterranean species. According to our ancestral character state reconstruction results, ancestors of Fabeae had a basic chromosome number of 2n=14, an annual life form, and evenly hairy, dorsiventrally compressed styles. Conclusions: Fabeae evolved in the Eastern Mediterranean in the middle Miocene and spread from there across Eurasia, into Tropical Africa, and at least seven times to the Americas. The middle-Atlantic islands were colonized four times but apparently did not serve as stepping-stones for Atlantic crossings. Long-distance dispersal events are relatively common in Fabeae (seven per ten million years). Current generic and infrageneric circumscriptions in Fabeae do not reflect monophyletic groups and should be revised. Suggestions for generic level delimitation are offered.
- The Madeiran plants collected by Sir Hans Sloane in 1687, and his descriptionsPublication . Sequeira, Miguel Menezes de; Santos-Guerra, Arnoldo; Jarvis, Charles E.; Oberli, Andreas; Carine, Mark A.; Maunder, Michael; Francisco-Ortega, JavierThe Macaronesian Islands comprise the Atlantic archipelagos of Azores, Madeira, Selvagens, Canaries and Cape Verde. These islands were a major focus for plant exploration during the 17th and 18th centuries. Sir Hans Sloane (1660–1753), one of the most important patrons and sponsors of natural sciences and botanical research, visited Madeira on his way to Jamaica in 1687. Although he stayed in Madeira for only three days, he collected plant specimens of 38 taxa (including one brown alga) and made important observations concerning the flora and fauna of Madeira from near Funchal. Sixty-six polynomial names of plants from the island are recorded in Sloane’s published work along with 18 copperplate engravings, ostensibly from Madeira, although our study shows that only thirteen of them are of taxa occurring on the island. Fourteen of the sixty-six polynomials reported by Sloane relate to Macaronesian endemic taxa, six of them restricted to Madeira. Our study shows that nine of the fifteen polynomials that he putatively recorded for Madeira and/or the Antilles or for which he was unsure of their origin are from the West Indies and do not occur on this Macaronesian island. Two of the taxa that are listed for Madeira and the Carib bean Islands were likely to be present in both insular systems. Although there is evidence of earlier botanical explorations in Macaronesia, the herbarium collections made by Sloane in Madeira represent the earliest documented plant hunting expedition to Macaronesia, and Sir Hans Sloane can be considered as one of the pioneers of botanical exploration in these Atlantic Islands. Sloane’s records provide an early floristic study of a diverse island flora.