A new species of Scaphosepalum (Orchidaceae, Pleurothallidinae) from eastern Ecuador

The genus Scaphosepalum comprises a group of epiphytic orchids, distinguished by their non-resupinate flowers and prominent osmophores located on the distal portion of the synsepal. With over 60 recognised species, Scaphosepalum is distributed throughout the tropical Americas, with its highest diversity in Colombia and Ecuador. Recent explorations in the Eastern Andes and the Cordillera del Cóndor in south-eastern Ecuador led to the discovery of several new orchid species, including an endemic Scaphosepalum taxon. Many regions remain underexplored, leaving the orchid flora to continually reveal previously undocumented diversity. Herein, we describe and illustrate Scaphosepalum lesterlapoi , as new species discovered in the Andean-Amazonian piedmont of eastern Ecuador. This taxon was initially misidentified as S. medinae based on photographic records. It is compared with S. pleurothallodes and S. medinae , from which it is distinguished by its maroon to yellow-maroon flowers and the rhombic-spathulate shape of the petals. This denotes a marked difference to the yellow flowers spotted with red and the obovate petals of S. pleurothallodes or the lavender with white cells and light brown flowers and the narrowly obtuse petals of S. medinae . The new species is currently known from three localities in the Quimi and Talag River basins. Due to its restricted distribution, small population size and threats from cattle grazing and mining activities, we propose its classification as Critically Endangered under the B criterion of the IUCN.