New island record and conservation status of Puerto Rican Bank endemic plant species, Ruehssia woodburyana (Acev.-Rodr.) Goyder, comb. nov., formally transferred from Marsdenia

Background: Thought to be endemic to the Commonwealth of Puerto Rico, Ruehssia woodburyana (Apocynaceae) was recently discovered at a single location on Norman Island in the British Virgin Islands. Despite an increase in the extent of occurrence and area of occupancy, this species meta-population is very limited with a total of 37 individuals known in the wild. The largest subpopulation, on Mona Island, has only 26 individuals. The species suitable habitat is experiencing a continuing decline due to urban development, grazing by feral ungulates and human-induced forest fires. Conservation action is urgently needed and should be directed towards establishing genetically representative ex situ collections, such as seed for long term storage and live material for propagation. This species is evaluated as Critically Endangered (CR), based on Criteria C2a(i)+D, according to the IUCN Red List Categories and Criteria (version 3.1) and guidelines (Subcommittee IUCN Standards and Petitions 2016). New information: Extensive and regular surveys to the region enable the discovery of new plant records for different countries and islands. In this paper, we record a new island record for Ruehssia woodburyana on Norman Island, in the British Virgin Islands and discuss the species conservation status. Marsdenia woodburyana is transferred to the genus Ruehssia to reflect the resurrection of that genus for species of Marsdenia native to the New World.