Catasetum krahlii (Orchidaceae, Catasetinae): a new and threatened species from the Brazilian Amazon

In the present study we propose a new Catasetum taxon belonging to the group of species with symmetrical and converging antennae. It was found in a vegetation of "terra firme" and "campinarana" in the central Brazilian Amazon. A detailed description of the taxon is given as well as a photograph plate and comments relating to distribution, habitat, phenology and conservation status. It is compared to C. rivularium and C. barbatum which are sympatric species and somewhat similar to the new taxon. Furthermore, we present a key to Catasetum species with symmetrical and convergent antennae occurring in the Brazilian Amazon.