Restructuring of the "Macaronesia" biogeografic unit: a marine multi-taxon biogeographical approach

The Azores, Madeira, Selvagens, Canary Islands and Cabo Verde are commonly united under the term “Macaronesia”. This study investigates the coherency and validity of Macaronesia as a biogeographic unit using six marine groups with very different dispersal abilities: coastal fishes, echinoderms, gastropod molluscs, brachyuran decapod crustaceans, polychaete annelids, and macroalgae. We found no support for the current concept of Macaronesia as a coherent marine biogeographic unit. All marine groups studied suggest the exclusion of Cabo Verde from the remaining Macaronesian archipelagos and thus, Cabo Verde should be given the status of a biogeographic subprovince within the West African Transition province. We propose to redefine the Lusitanian biogeographical province, in which we include four ecoregions: the South European Atlantic Shelf, the Saharan Upwelling, the Azores, and a new ecoregion herein named Webbnesia, which comprises the archipelagos of Madeira, Selvagens and the Canary Islandsinfo:eu-repo/semantics/publishedVersio

Advances in angraecoid orchid systematics in Tropical Africa and Madagascar: new taxa and hypotheses for their diversification

Les angrecoïdes constituent le groupe d'orchidées épiphytes le plus diversifié dans les Afrotropiques, comprenant environ 800 espèces. Bien que beaucoup d'attention leur aient été porté, certaines énigmes taxonomiques subsistent au sein des angraecoïdes, et les facteurs à l'origine de leur diversification rapide sont encore inconnus. Les angraecoïdes présentent une remarquable diversité en termes du nombre chromosomique, en faisant un système très approprié pour explorer l'impact des changements caryotypiques sur la cladogenèse, les taux de spéciation/extinction et la diversification morphologique dans le contexte des fluctuations climatiques en Afrique tropicale depuis le Miocène. En outre, grâce au large éventail des longueurs d'éperon nectarifère que ces orchidées présentent, elles ont fait l'objet, depuis Darwin, de recherches approfondies dans le cadre des interactions plantes-animaux. Ici, sur base de nouveaux arbres phylogénétiques produits en utilisant ITS-1 ainsi que cinq marqueurs plastidiques et englobant environ 40 % des espèces, nous fournissons un nouveau cadre taxonomique pour les principales lignées d'Angraecinae. De plus, le cadre taxonomique des angraecoïdes est mis à jour avec, notamment, la description de trois nouveaux genres et six nouvelles espèces. Cette nouvelle hypothèse phylogénétique nous a permis d'étudier si les changements des caryotypes et des pollinisateurs ont pu être les moteurs de la radiation évolutive des angraecoïdes. La reconstruction des états ancestraux du nombre chromosomique révèle une histoire caryotypique dominée par la dysploïdie descendante en Afrique tropicale continentale, où environ 90 % des espèces dérivent d'au moins un changement inféré de n = 17–18 à n = 25 au Miocène moyen. L’examen des intervalles de position du nectar par rapport au pollen dans les Afrotropiques a révélé qu'environ 3 % de la flore des angiospermes de Madagascar est probablement pollinisée par des sphinx, alors que cette proportion est d'environ 1,6 % en Afrique continentale. Les nombreux changements de guilde de pollinisateur vers la sphingophilie ayant eu lieu chez les angraecoïdes seraient à l’origine d’environ 31 % des espèces, y compris certaines lignées ayant les taux de spéciation les plus élevés. En dehors du domaine de la sphingophilie, de nouveaux exemples possibles d’ornithophilie, de phalénophilie et de pollinisation par des tipules à long proboscis/microlepidoptères sont discutées. Des perspectives de recherche concernant l'évolution génomique chez les angraecoïdes et l'impact et les mécanismes des changements des sites de fixation des pollinies sont suggérées. Enfin, certaines priorités pour l’observation de nouveaux pollinisateurs sur le terrain et les frontières de l’alpha et bêta-taxonomie chez les angraecoïdes sont présentées.Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

A new Ypsilopus (Orchidaceae, Angraecinae) from Zimbabwe and notes on the parallel evolution of extreme column exsertion in African angraecoids

Background and aims – A preliminary review of hawkmoth-pollinated angraecoids from Africa unveiled a remarkable case of parallel evolution of extreme column exsertion between the two species formerly classified in in the defunct genus Barombia. These belong to one clade of Aerangis, including A. gracillima and A. stelligera, and Ypsilopus sect. Barombiella, including Y. amaniensis and Y. schliebenii. The exploration of the geographical distribution of these two clades, followed by an examination of morphological variation within Y. sect. Barombiella, revealed that the disjunct population identified as Y. amaniensis from Zimbabwe represents an undescribed species. Material and methods – Occurrence records of Ypsilopus amaniensis, Y. schliebenii, Aerangis gracillima, and A. stelligera were comprehensively mapped and distribution patterns were visually analysed. Pollination syndromes and pollinaria attachment sites were inferred based on a review of floral and hawkmoth morphology. Standard herbarium practices and mining of photographs of wild and cultivated plants in social media allowed the description of the novelty. Key results – Ypsilopus zimbabweensis sp. nov. (Y. sect. Barombiella) is a narrow endemic of significant horticultural interest and it is preliminarily assessed as Endangered. The evolution of a Barombia-type column presents a parallel geographical pattern in the Aerangis gracillima–A. stelligera clade and Ypsilopus sect. Barombiella and probably induced a shift of pollen placement sites in these sphingophilous species.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Two new species of Rhipidoglossum (Orchidaceae: Angraecinae) from Tanzania and Zimbabwe

Two new species of angraecoid orchid from East and South-central Africa are described and illustrated. Rhipidoglossum lucieae is known from the Eastern Arc Mountains of Tanzania (West Usambaras) and has been misidentified as R. pulchellum in previous floristic treatments. Rhipidoglossum philatelicum is reported from the Eastern Highlands of Zimbabwe (Bvumba and Chimanimani Mts) and has been misclassified under R. subsimplex. Distribution maps and the conservation status of these two novelties are provided. Future directions in epiphytic orchid species discovery in eastern tropical Africa are proposed.SCOPUS: ar.jDecretOANoAutActifinfo:eu-repo/semantics/publishe

A new genus of angraecoid orchids (Orchidaceae: Angraecinae) with highly distinctive pollinaria morphology, including three new species from tropical west and central Africa

A recent large phylogenetic tree for the angraecoid orchids has shown that the Afrotropical genus Diaphananthe is polyphyletic with a small group of four species sister to Aerangis and Eurychone. These species have diagnostic morphological features different from any other angraecoids, notably an erose to fringed surface of the stipes and a calceiform viscidium. Diaphananthe quintasii, which has been regarded as conspecific with D. rohrii, is reinstated as a valid species and lectotypified, and Diaphananthe alfredii and Rhipidoglossum magnicalcar are put in synonymy under D. quintasii. To accommodate this group of species, along with three new taxa from West and Central Africa, a new genus named Kylicanthe is here described. Four new combinations are thus proposed, and K. bueae is chosen as the type species of the new genus and neotypified. Additionally, K. arcuata, K. cornuata, and K. perezverae are described as new species. An identification key for Kylicanthe and allied genera is presented, as well as one for the seven species in the genus. Notes on ecology and distribution in addition to a preliminary assessment of conservation status following the IUCN Red List are also provided.SCOPUS: ar.jDecretOANoAutActifinfo:eu-repo/semantics/publishe

A revised concept of rhipidoglossum (Angraecinae, orchidaceae)

Following the production of a near-comprehensive generic phylogenetic analysis of African angraecoid orchids, paraphyly of the genus Rhipidoglossum relative to Cribbia, Margelliantha and Rhaesteria was in need of being resolved by integrating morphological observations into this newly available molecular framework. Accordingly, we critically revised the diagnostic traits of each genus by examining about 700 herbarium specimens ascribable to 50 species of Rhipidoglossum and its satellite genera. Cribbia, Margelliantha and Rhaesteria are here lumped with Rhipidoglossum, along with Angraecopsis pusilla and Diaphananthe millarii. The presence of pollinaria with two separate disk-shaped viscidia, a trilobed, non-papillate rostellum with midlobe more prominent than lateral lobes and an undivided lip are diagnostic of this more inclusive concept of Rhipidoglossum. In line with this new taxonomic arrangement, 11 new combinations in Rhipidoglossum are made, and Margelliantha lebelii is moved to Diaphananthe and first reported for Uganda.SCOPUS: ar.jinfo:eu-repo/semantics/publishe