Filogenia das espécies americanas de Rhynchosia Lour. (Leguminosae, Papilionoideae, Phaseoleae) e estudos taxonômicos do gênero no Brasil
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Data
2018-02-05
Autores
Bezerra, Luísa Maria de Paula Alves
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Universidade Estadual Paulista (Unesp)
Resumo
Rhynchosia Lour. possui distribuição pantropical, apresentando dois principais centros de diversidade para as cerca de 230 espécies, um na África (ca.140 spp.) e outro nas Américas, onde é registrada a ocorrência de 55 espécies, das quais 19 ocorrem no Brasil. O mais recente tratamento taxonômico do gênero foi publicado por Grear em 1978, que tratou apenas as espécies americanas. Neste trabalho, Grear (l.c.) propôs duas seções (R. sect. Copisma (E.Mey.) Endl. e R. sect. Arcyphyllum (Elliott) Torr. & A. Gray. Nenhum trabalho molecular foi realizado para as espécies americanas de Rhynchosia para apoiar esta classificação taxonômica. Estudos de filogenia molecular existentes enfocam a tribo e nestes trabalhos Rhynchosia é apontado como monofilético e mais relacionado com Eriosema, apesar da baixa amostragem utilizada destes gêneros. Do ponto de vista morfológico Rhynchosia é bastante uniforme, dificultando a delimitação das espécies. Pode ser caracterizado por apresentar folhas unifolioladas ou trifolioladas com estípulas persistentes ou caducas, inflorescências racemosas laxas ou congestas, com flores amarelas, cálice com cinco lobos bem desenvolvidos, e fruto do tipo legume, com duas sementes. Considerando o pouco conhecimento sobre as relações filogenéticas em Rhynchosia, enfatizando que nenhum trabalho molecular com as espécies americanas foi realizado, e a riqueza de táxons do gênero existentes no Brasil, um estudo taxonômico para as espécies de Rhynchosia no Brasil e a filogenia com dados moleculares das espécies americanas foram realizados com o intuito de testar o monofiletismo do gênero, com ênfase nas duas seções ocorrentes nas Américas e elucidar as relações das espécies de Rhynchosia.
Rhynchosia Lour. has a pantropical distribution, with two main centers of diversity for its about 230 species, one in Africa (ca. 140 spp.) and the other in the Americas, where 55 species are recorded, of witch 19 occur in Brazil. The most recent taxonomic treatment of the genus was published by Grear in 1978, which treated only the American species. In this work, Grear (l.c.) proposed two sections (R. sect. Copisma (E. Mey) Endl. and R. sect. Arcyphyllum (Elliott) Torr. & A. Gray. No molecular work was done for the American Rhynchosia species to support this taxonomic classification. Existing molecular phylogenetic studies are those focusing on the tribe and in these works Rhynchosia is designated as monophyletic and more related to Eriosema, despite the low sampling used for these genera. From the morphological point of view Rhynchosia it is quite uniform, making it difficult to delimit the species. It can be characterized by the presence of unifoliolate or trifoliolate leaves with persistent or deciduous stipules, lax or congested racemic inflorescences, yellow flowers, calyx with five well developed lobes, and a legume fruit with two seeds. Considering the little knowledge about the phylogenetic relationships in Rhynchosia, emphasizing that no comprehensive molecular work with the American species has been carried out so far, and the richness of taxa of the genus existing in Brazil, a taxonomic study for the species of Rhynchosia in Brazil and the phylogeny with molecular data of the American species was carried out in order to test the monophyly of the genus, with emphasis in the two sections occurring in the Americas and to elucidate the relations among the Rhynchosia species.
Rhynchosia Lour. has a pantropical distribution, with two main centers of diversity for its about 230 species, one in Africa (ca. 140 spp.) and the other in the Americas, where 55 species are recorded, of witch 19 occur in Brazil. The most recent taxonomic treatment of the genus was published by Grear in 1978, which treated only the American species. In this work, Grear (l.c.) proposed two sections (R. sect. Copisma (E. Mey) Endl. and R. sect. Arcyphyllum (Elliott) Torr. & A. Gray. No molecular work was done for the American Rhynchosia species to support this taxonomic classification. Existing molecular phylogenetic studies are those focusing on the tribe and in these works Rhynchosia is designated as monophyletic and more related to Eriosema, despite the low sampling used for these genera. From the morphological point of view Rhynchosia it is quite uniform, making it difficult to delimit the species. It can be characterized by the presence of unifoliolate or trifoliolate leaves with persistent or deciduous stipules, lax or congested racemic inflorescences, yellow flowers, calyx with five well developed lobes, and a legume fruit with two seeds. Considering the little knowledge about the phylogenetic relationships in Rhynchosia, emphasizing that no comprehensive molecular work with the American species has been carried out so far, and the richness of taxa of the genus existing in Brazil, a taxonomic study for the species of Rhynchosia in Brazil and the phylogeny with molecular data of the American species was carried out in order to test the monophyly of the genus, with emphasis in the two sections occurring in the Americas and to elucidate the relations among the Rhynchosia species.
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Palavras-chave
Cajaninae, Fabaceae, Eriosema, Sistemática Vegetal, Plant Systematic