A new species of Habenaria (Orchidaceae, Asparagales) and a checklist of Orchidaceae from limestone outcrops of Brazil

Abstract

Habenaria karstica J.A.N.Bat. sp. nov., a new species from limestone outcrops (i.e., karst) in the State of Minas Gerais, Brazil, is described. The new species is ecologically very distinct since it is the only Neotropical species of the genus that grows on limestone outcrops under full sun, associated with mat-forming saxicolous plants. It is morphologically similar to species of the Habenaria repens complex, and separation is only possible through a combination of morphological characters. Bayesian and parsimony phylogenetic analyses based on nuclear (rDNA ITS, ETS) and plastid (matK-trnK, rps16-trnK) DNA markers revealed that H. karstica belongs to H. sect. Spathaceae. The new species, however, differs in floral morphology from the other species in this clade. A survey of the literature and public plants datasets revealed 122 species and 58 genera of Orchidaceae in karsts of Brazil. Although small compared to the family’s diversity in the country, Orchidaceae is among the families with the highest number of species in some karst localities. Our results indicate that approximately 97% of Orchidaceae found in karsts of Brazil is not limited to limestone outcrops areas, and that species composition of each locality is primarily determined by the regional flora and the biome in which it is located.

Checklist and molecular phylogenetics reveal three taxonomic novelties in Habenaria (Orchidaceae, Orchidoideae) from Chapada dos Veadeiros, Goiás, Brazil

“…The relationships recovered were similar to those of earlier molecular phylogenetic studies (Batista et al 2013(Batista et al , 2014(Batista et al , 2016(Batista et al , 2017(Batista et al , 2022a…”

“…Based on this analysis, we selected some terminals for a second analysis using the dataset of Pedron et al (2014), including some species addressed in later studies (Batista et al 2014(Batista et al , 2016(Batista et al , 2017Cruz-Lustre et al 2022;Lau et al 2021) and 37 new sequences from 11 species (12 terminals) that were generated for this study. For the outgroup, encompassing old world taxa, we used the same dataset as Batista et al (2022a), which consists of a selected sampling based on the studies of Jin et al (2017) and Ngugi et al (2020), comprising representatives of the main clades of Asian and African Habenaria and related genera. The final data set consisted of the combined ITS, ETS, matK-trnK and rps16-trnK DNA sequences of 105 terminals of 103 taxa, including 85 terminals of 83 Neotropical Habenaria taxa containing most subclades of Neotropical Habenaria (Batista et al 2013).…”

“…Efforts to resolve the taxonomy of Brazilian species of Habenaria have intensified in the last years with the study of species complexes and the description of several new species (Batista et al 2017(Batista et al , 2022aCruz-Lustre et al 2020, 2022Lau et al 2021). Nevertheless, for the Chapada dos Veadeiros at least three morphotypes of the Habenaria nuda complex and some taxa associated with 1) are still unresolved and additional studies are needed to uncover the identity and taxonomy of these taxa.…”

“…Most subclades of Neotropical Habenaria, such as subclades 1, 2, 3 (Cruz-Lustre et al 2022), 4, 8, 15, 20 (Batista et al 2018 (Batista et al 2022a). In addition to these differences within the subclades, some species pairs from the Cerrado Phytogeographic Domain recovered as sisters with high support, such as H. caldensis Kraenzl.…”