RESUMO
The papilionoid legume tribe Brongniartieae comprises a collection of 15 genera with disparate morphologies that were previously positioned in at least four remotely related tribes. The Brongniartieae displays a wide geographical disjunction between Australia and the New World and previous phylogenetic studies had provided conflicting results about the relationships between the American and Australian genera. We carry out phylogenetic analyses of (1) a plastid matK dataset extensively sampled across legumes to solve the enigmatic relationship of the Cuban-endemic monospecific genus Behaimia; and (2) multilocus datasets with focus on all genera ever referred to Brongniartieae. These analyses resulted in a well-resolved and strongly-supported phylogenetic tree of the Brongniartieae. The monophyly of all American genera of Brongniartieae is strongly supported. The doubtful position of the Australian genus Plagiocarpus is resolved within a clade comprising all Australian genera. Behaimia has been traditionally classified in tribe Millettieae, but our new molecular data and re-assessment of morphological traits have resolved the genus within the early-branching papilionoid tribe Brongniartieae. Characters including the pinnately multifoliolate (vs. unifoliolate) leaves, a sessile (vs. stipitate) ovary, and an indehiscent or late dehiscent one-seeded pod distinguish Behaimia from its closer relatives, the South American genera Cyclolobium and Limadendron.
Assuntos
Fabaceae/classificação , Filogenia , Teorema de Bayes , Núcleo Celular/genética , Cuba , Plastídeos/genéticaRESUMO
Recent deep-level phylogenies of the basal papilionoid legumes (Leguminosae, Papilionoideae) have resolved many clades, yet left the phylogenetic placement of several genera unassessed. The phylogenetically enigmatic Amazonian monospecific genus Petaladenium had been believed to be close to the genera of the Genistoid Ormosieae clade. In this paper we provide the first DNA phylogenetic study of Petaladenium and show it is not part of the large Genistoid clade, but is a new branch of the Amburaneae clade, one of the first-diverging lineages of the Papilionoideae phylogeny. This result is supported by the chemical observation that the quinolizidine alkaloids, a chemical synapomorphy of the Genistoids, are absent in Petaladenium. Parsimony and Bayesian phylogenetic analysis of nuclear ITS/5.8S and plastid matK and trnL intron agree with a new interpretation of morphology that Petaladenium is sister to Dussia, a genus comprising â¼18 species of trees largely confined to rainforests in Central America and northern South America. Petaladenium, Dussia, and Myrospermum have papilionate flowers in a clade otherwise with radial floral symmetry, loss of petals or incompletely differentiated petals. Our phylogenetic analyses also revealed well-supported resolution within the three main lineages of the ADA clade (Angylocalyceae, Dipterygeae, and Amburaneae). We also discuss further molecular phylogenetic evidence for the undersampled Amazonian genera Aldina and Monopteryx, and the tropical African Amphimas, Cordyla, Leucomphalos, and Mildbraediodendron.
Assuntos
Fabaceae/classificação , Filogenia , Teorema de Bayes , América Central , DNA de Plantas/genética , DNA Espaçador Ribossômico/genética , Fabaceae/química , Íntrons , Modelos Genéticos , América do Norte , Folhas de Planta/química , Plastídeos/genética , Análise de Sequência de DNARESUMO
This study presents a taxonomic account of the Papilionoideae (Leguminosae) from remnants of Atlantic Forest in the Brazilian state of Rio Grande do Norte. We recorded 68 species and 32 genera within the following tribes: Phaseoleae (11 genera/24 species), Dalbergieae (9/20), Swartzieae (3/3), Millettieae (2/4), Sophoreae (2/2), Abreae (1/1), Crotalarieae (1/3), Desmodieae (1/7), Indigofereae (1/3), and Sesbanieae (1/1). Ten genera and 32 species are newly recorded for the flora of Rio Grande do Norte. The most species-rich genera were Desmodium (7 species), Centrosema (5), Stylosanthes (5), Aeschynomene (4), and Macroptilium (4). Herbaceous and shrubby species have predominated with 60% (41 spp.) of the total species diversity, following by the vines and lianas with 28% (19 spp.) and the trees with only 12% (8 spp.). Identification key, descriptions, diagnostic morphological characters, geographic distribution, and illustrations are also provided.
O presente trabalho consiste no levantamento florístico e caracterização taxonômica das espécies de Papilionoideae (Leguminosae) presentes nos remanescentes de Mata Atlântica no Rio Grande do Norte. Foram registradas 68 espécies e 32 gêneros distribuídos nas tribos Phaseoleae (11 gêneros/24 espécies), Dalbergieae (9/20), Swartzieae (3/3), Millettieae (2/4), Sophoreae (2/2), Abreae (1/1), Crotalarieae (1/3), Desmodieae (1/7), Indigofereae (1/3) e Sesbanieae (1/1). Estão sendo registrados pela primeira vez dez gêneros e 32 espécies na flora do estado. Os gêneros que apresentaram a maior riqueza de espécies foram Desmodium (7 espécies), Centrosema (5), Stylosanthes (5), Aeschynomene (4) e Macroptilium (4). Quanto ao hábito, predominaram o herbáceo e arbustivo com 60% (41 spp.), seguido do trepador e lianescente com 28% (19 spp.) e o arbóreo com apenas 12% (8 spp.). São apresentadas chave de identificação, descrições, caracteres diagnósticos, distribuição geográfica e ilustrações das espécies estudadas.