One more word on Patagonian Ulota macrodontia: Ulota brachypoda sp. nov. (Orthotrichaceae, Bryophyta)

Abstract The bryophyte genus Ulota has its main diversification area in Patagonia, with 18 currently accepted species, all of which are endemic to the area. Despite this richness, ongoing studies indicate the existence of hitherto unknown species in this territory. However, the strong resemblance between species often complicates the discrimination of new taxa, making the use of integrative taxonomy approaches compulsory. During surveys conducted in past decades, a morphotype of a Ulota, closely resembling Ulota macrodontia, was discovered coexisting with this species. Ulota macrodontia is characterized by unique peristomial features within the genus, and the variant morphotype shares these characteristics while displaying some distinct gametophytic and sporophytic features. Biometric analyses demonstrate that the differences are stable, and without intermediate states. The results obtained from the analyses of one nuclear and four plastid loci reveal a close relationship between both morphotypes, with the samples of U. macrodontia forming a well-supported monophyletic group. We propose to treat the new morphotype at species level (Ulota brachypoda sp. nov.), discussing why this is the most appropriate taxonomic rank, and we provide a detailed and illustrated description. Additionally, a distribution map of the two endemics is included.