O gênero Amauropelta Kunze (Thelypteridaceae) no Brasil

Abstract

Thelypteridaceae Pic. Serm is one of the largest families of ferns, comprising approximately 950 species, of which 300 occur in the Neotropical region. The genus Amauropelta comprises ca. 200 species, with most of them exclusively distributed in the neotropics, and only 12 in the paleotropics. Amauropelta is characterized by the proximal pinnae gradually to abruptly reduced, veins from adjacent segments free, and meeting margin above the sinus, spores with densely reticulate surface and a base chromosome number (x) of 29. Amauropelta was treated as a subgenus of Thelypteris, however, recent phylogenetic studies based on molecular data confirmed the monophyly of the group and also provided valid support to characterize the taxon as a genus, which is also corroborated by the morphologic characters previously mentioned. The genus has hitherto been poorly studied specially due to difficulties in identification of microscopic characteristics and divergences in species circumscription. The aim of the current study is to contribute to the taxonomic treatment of the Amauropelta genus in Brazil. The study was performed analysing the indument, spores and other characteristics of plants recently collected during field trips, specimens from national and international herbaria and also type material. A total of 35 species of Amauropelta were recognized to occur in Brazil, with two of which are being considered as new species. From the overall amount of species recognized, 18 occur strictly in Brazil being mostly distributed in moist forests and grassland formations located 1000 meters above sea level. Only five of the identified species have current valid names in the Amauropelta genus, therefore, 28 species are being combined in Amauropelta.