Sistemática de Maripeae (Convolvulaceae): uma tribo predominantemente amazônica

Abstract

The tribe Maripeae belongs to Convolvulaceae Juss., a family of great importance in feeding, with Ipomoea batatas (L.) Lam. (sweet potato), and ornamentation, with the species known as morning glory. The tribe is considered monophyletic, the current circumscription includes the genera Dicranostyles Benth., Lysiostyles Benth. and Maripa Aubl., with 36 species distributed in tropical America, predominantly in the Amazonian lowlands. Maripeae is composed exclusively of lianas (woody climbers), mainly characterized by elliptical to oblong, non-cordate, and coriaceous leaves, white, pink, or rarely purple corolla flowers, and indehiscent fruits with a woody pericarp. The genera of the tribe Maripeae were traditionally recognized in the tribe Erycibeae, along with the genera Humbertia Lam. (Madagascar) and Erycibe Roxb. (Asia). However, a molecular phylogeny of Convolvulaceae indicated the polyphyly of Erycibeae (sensu lato), with the American genera emerging as a monophyletic group. This thesis aims at a taxonomic review and molecular phylogeny of the tribe Maripeae, to document its diversity, test its monophyly and of the recognized genera, analyze the evolutionary relationships between the taxa, and contribute to the conservation of its species. The development of this research includes the revision of specimens deposited in the main herbaria holding Amazonian collections, fieldwork for the collection of specimens and DNA samples, phylogenetic analyses based on plastid DNA (regions rbcL, atpB, matK, rps16, trnL-F, psbE-J) and RNAr 35S nuclear region. The results obtained are structured in four chapters in the format of a scientific article: i) a phylogeny molecular and circumscription in the tribe Maripeae, based on sequences of 33 samples of Maripeae and 30 of out-group; ii) a description of a new species from Central Amazon (Dicranostyles yrypoana M.P.Pastore); iii) a description of a new species of Maripa from the Andean tropical forest (Maripa daironii M.P.Pastore and M. marimba M.P.Pastore); iv) a monograph of Dicranostyles with 19 species accepted; v) a monograph of Maripa with 20 species accepted. This study presents a treatment for 41 species accepted in Maripeae, with distribution centered in the Amazon and occurrences documented in Andean, Pacific, and Atlantic Coastal Cordillera regions, Southern Mexico, and the Brazilian Cerrado. The taxonomy revision includes a proposal for the description of four new species of Dicranostyles, and two new species of Maripa, the re-establishment of Maripa kuhlmannii (Hoehne) Ducke, seven new synonyms, and the designation of one neotype and 18 lectotypes. The molecular phylogeny strongly confirms the monophyly of the tribe Maripeae, and the Dicranostyles and Maripa genera are verified as paraphyletic. Maripa rugosa Ducke emerges as a sister lineage of Dicranostyles, however, the new genus Gen. nov. M.Pastore & P.L.Viana is proposed to accommodate Maripa rugosa and a new species described. The monospecific Lysiostyles is nested within the Dicranostyles, resulting in a proposal of the new combination of L. scandens Benth. in Dicranostyles. The evolutionary relationships between the species are discussed, although it is necessary to include more species in the molecular sampling to resolve uncertain relationships. This research obtained important results in the delimitation of Maripeae, presenting the first molecular phylogeny of a little-known and peculiar group of plants with diversity centered in the Amazon Forest.