Systematics of Western Indian Ocean Octotropideae

The tribe Octotropideae remains one ofthe leastknown groups of Paleotropical Rubiaceae. The Western Indian Ocean and Madagascar, in particular, represents a center of diversity with a high degree o f endemism. Canephora, Chapelieria, Flagenium, Gallienia, Jovetia, and Lemyrea are some of the genera that are only found on Madagascar. Most o f the Malagasy genera are in need of taxonomic revisión and there are several species that are as o f yet undescribed. However, the generic delimitations are still not fully resolved, and molecular phylogenetic studies also indícate that not all genera are monophyletic as presently circumscribed. The aims of this study are to infer the phylogeny of Octotropideae sensu strictu using plastid and nuclear DNA data, and to clarify generic delimitations of the Malagasy members. Results will be presented and discussed

Patterns of distribution and diversification in the Madagascar-centred tribe Danaideae (Rubiaceae)

The tribe Danaideae is centred in the Western Indian Ocean Región (including Madagascar and the neighbouring Comoras, Mascarenes, and Seychelles archipelagos). This group o f plants encompasses three genera, the Malagasy endemic Payera (with 15 species) and Schismatoclada (with 47 species), and the mostly Western Indian Ocean genus Danais (with 42 species). The members of the tribe are restricted to three bioclimate zones in Madagascar: humid zone harbouring littoral forests and lowland rainforests along the east; subhumid zone covering highland rainforests along the central highlands; and montane zone mostly in the central highlands above the subhumid zone and characterized by ericoid thickets. We reconstructed a robust phylogeny of Danaideae to investígate the geographic and diversification patterns in Payera and Schismatoclada, using the Bayesian method and combined plastid (matK, ndhF, and trnT-F) and nuclear (nrITS) data. We sampled ca 75% o f species richness o f Payera and Schismatoclada, covering the entire geographic ranges o f Danaideae. The results of this study will be presented and discussed.The tribe Danaideae is centred in the Western Indian Ocean Región (including Madagascar and the neighbouring Comoras, Mascarenes, and Seychelles archipelagos). This group o f plants encompasses three genera, the Malagasy endemic Payera (with 15 species) and Schismatoclada (with 47 species), and the mostly Western Indian Ocean genus Danais (with 42 species). The members of the tribe are restricted to three bioclimate zones in Madagascar: humid zone harbouring littoral forests and lowland rainforests along the east; subhumid zone covering highland rainforests along the central highlands; and montane zone mostly in the central highlands above the subhumid zone and characterized by ericoid thickets. We reconstructed a robust phylogeny of Danaideae to investígate the geographic and diversification patterns in Payera and Schismatoclada, using the Bayesian method and combined plastid (matK, ndhF, and trnT-F) and nuclear (nrITS) data. We sampled ca 75% o f species richness o f Payera and Schismatoclada, covering the entire geographic ranges o f Danaideae. The results of this study will be presented and discussed

Evolution and biogeography of the Pavetteae tribe

With over 700 species, the Pavetteae are one o f the largest tribes in the subfamily Dialypetalanthoideae (formerly: Ixoroideae). Pavetteae representatives are characterized by a high morphological variation, especially regarding the reproductive characters (e.g., number of seeds per fruit, seed type and placentation). Representatives of the tribe occur throughout the Paleotropics in humid and dry vegetation types. In the Asian-Pacific región ca 300 species are currently described whereas on continental Africa and Madagascar (and Western Indian Ocean Islands) ca 350 and ca 80 species are present, respectively. Recently many new genera have been recognized among the Malagasy Pavetteae species (e.g. Tulearia). In addition, it is clear that within the paleotropical genus Tarenna there will be a split into different genera. Not only is the taxonomic history of the tribe rather complicated, also the biogeographical history and evolutionary patterns of the tribe remain understudied to date. Molecular phylogenetics combined with age inference methods, diversificaron analyses and ancestral area reconstruction clearly indicate that current diversity of the Pavetteae is the result of several dispersal events within the Paleotropical region. Moreover, several shifts in ecological preference have likely driven the evolutionary history within the Pavetteae

A new species of the genus Paederia (Rubiaceae) from the Petriky Forest, Taolagnaro, Madagascar

Volume: 10Start Page: 71End Page: 7

Evolution and trends in the Psychotrieae alliance (Rubiaceae)- a rarely reported evolutionary change of many-seeded carpels from one-seeded carpels

Bayesian and parsimony analyses of five plastid gene and nrITS regions from 58 Rubioideae (Rubiaceae) taxa further support the sister-group relationship between the African monotypic genus Schizocolea and the Psychotrieae alliance sensu Bremer & Manen. Our analyses show that the Psychotrieae alliance can be subdivided into in four well-supported clades: Schizocolea, (Schradereae(Gaertnereae(Mitchelleae-Morindeae s.s.))), Palicoureeae-Psychotrieae s.s., and Craterispermeae-Prismatomerideae. The relationships between the latter three clades remain unsettled. Our study further reveals much higher numbers of molecular autapomorphies of the tribes compared with those of molecular synapomorphies of two sister tribes or groups of tribes. Within the newly delimited Psychotrieae alliance a one-seeded carpel was inferred as ancestral and many- and two-seeded carpels evolved once each. We describe Mitchelleae to accommodate Damnacanthus and Mitchella and restrict Morindeae to include only Appunia, Coelospermum, Gynochthodes, Morinda, Pogonolobus, and Syphonandrium. Mitchelleae is characterized e.g., by placentae inserted near the top of the septum and a single campylotropous ovule per carpel, while Morindeae s.s. has massive and T-shaped placentae inserted in the middle of the septum and two anatropous ovules per carpel

Rare and enigmatic genera (Dunnia, Schizocolea, Colletoecema), sisters to species-rich clades: phylogeny and aspects of conservation biology in the coffee family

Despite extensive efforts, parts of the phylogeny of the angiosperm family Rubiaceae has not been resolved and consequently, character evolution, ancestral areas and divergence times of major radiations are difficult to estimate. Here, phylogenetic analyses of 149 taxa and five plastid gene regions show that three enigmatic genera are sisters to considerably species rich clades. The rare and endangered species Dunnia, endemic to southern Guangdong, China, is sister to a large clade in the Spermacoceae alliance; the rarely collected Schizocolea from western tropical Africa is sister to the Psychotrieae alliance; and Colletoecema from central tropical Africa is sister to remaining Rubioideae. The morphology of these taxa has been considered "puzzling". In combination with further morphological studies, our results may help understanding the apparently confusing traits of these plants. Phylogenetic, morphological, and geographical isolation of Dunnia, Schizocolea and Colletocema may indicate high genetic diversity. They are lone representatives of unique lineages and if extinct, the loss would not only mean loss of genetic diversity of a single species but of an entire lineage

New taxa and nomenclatural notes on the flora of the Marojejy Massif, Madagascar. III. Rubiaceae. A new species of Sabicea

Volume: 21Start Page: 41End Page: 4

Age and historical biogeography of the pantropically distributed Spathelioideae (Rutaceae, Sapindales)

Aim The family Rutaceae (rue family) is the largest within the eudicot order Sapindales and is distributed mainly in the tropical and subtropical regions of both the New World and the Old World, with a few genera in temperate zones. The main objective of this study is to present molecular dating and biogeographical analyses of the subfamily Spathelioideae, the earliest branching clade (which includes eight extant genera), to interpret the temporal and spatial origins of this group, ascertaining possible vicariant patterns and dispersal routes and inferring diversification rates through time. Location Pantropics. Methods A dataset comprising a complete taxon sampling at generic level (83.3% at species level) of Spathelioideae was used for a Bayesian molecular dating analysis (beast). Four fossil calibration points and an age constraint for Sapindales were applied. An ancestral area reconstruction analysis utilizing the dispersalextinctioncladogenesis model and diversification rate analyses was conducted. Results Dating analyses indicate that Rutaceae and Spathelioideae are probably of Late Cretaceous origin, after which Spathelioideae split into a Neotropical and a Palaeotropical lineage. The Palaeotropical taxa have their origin inferred in Africa, with postulated dispersal events to the Mediterranean, the Canary Islands, Madagascar and Southeast Asia. The lineages within Spathelioideae evolved at a relatively constant diversification rate. However, abrupt changes in diversification rates are inferred from the beginning of the Miocene and during the Pliocene/Pleistocene. Main conclusions The geographical origin of Spathelioideae probably lies in Africa. The existence of a Neotropical lineage may be the result of a dispersal event at a time in the Late Cretaceous when South America and Africa were still quite close to each other (assuming that our age estimates are close to the actual ages), or by Gondwanan vicariance (assuming that our age estimates provide minimal ages only). Separation of land masses caused by sea level changes during the Pliocene and Pleistocene may have been triggers for speciation in the Caribbean genus Spathelia.status: publishe

A phylogeny of Urophylleae (Rubiaceae) based on rps16 intron data

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 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 consisting 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