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Ítem (2922) Proposal to conserve the name Loasa rudis (“Nasa rudis”) against L. rhoeadifolia (Loasaceae)(2022-10-17) Acuña Castillo, Rafael; Weigend, MaximilianThe genus Nasa was established by Weigend in 2006, encompassing species previously classified under Loasa. The distinction between the two genera is supported by the presence of a single bract per flower, a unique structure of the nectar scale, and molecular evidence. Among the widely collected and distributed taxa in Nasa is N. triphylla subsp. rudis, which spans from southern Mexico to Panama. Recent molecular evidence suggests elevating N. triphylla subsp. rudis to species rank, as it is morphologically and phylogenetically closer to N. dyeri than to the type subspecies of N. triphylla. N. rudis and N. dyeri exhibit distinct characteristics in comparison to N. triphylla, including robust basal stems, dark green calli at the base of petioles, and petals with long filiform appendages. N. rudis can be differentiated from N. dyeri by stem characteristics, stinging trichome cover, and pedicel length. The history of nomenclature for this taxon involves various names under Loasa, and the name "Loasa rhoeadifolia" is considered a synonym. Due to the lack of recognizable type material and the established usage of the name "Loasa rudis," it is recommended to conserve the name Loasa rudis for nomenclatural stability and to avoid further confusion.Ítem A biogeographical evaluation of high-elevation myxomycete assemblages in the northern Neotropics(2011-08) Rojas Alvarado, Carlos Alonso; Stephenson, Steven L.; Valverde González, Randall; Estrada Torres, ArturoThis study represented an effort to apply some of the relatively well-known biogeographical and macroecological models to the observed structure of myxomycete assemblages, with emphasis on the northern Neotropical region. A series of 28 experimental plots located in 14 study sites within five different countries was surveyed during two consecutive years using a standard methodology that included both field collections and specimens obtained from moist chamber cultures. Results showed that myxomycetes in high-elevation areas of the northern Neotropics seem to have different levels of preference for macro- and microenvironments, varying degrees of niche breadth and overlap, and different patterns of species occurrence in comparable areas. In a similar manner, species assemblages along a latitudinal gradient that extends from Mexico to Costa Rica showed a decreasing level of similarity with an assemblage studied in the temperate forests of the eastern United Stated and were clearly distinct from an assemblage in Thailand.Ítem A call-and-response system facilitates group cohesion among disc-winged bats(2013) Chaverri Echandi, Gloriana; Gillam, Erin H.; Kunz, Thomas H.Acoustic signals are important in maintaining group cohesion, particularly in highly mobile species. For these signals to facilitate group cohesion, individuals must be able to recognize, and respond to, calls emitted by group members. In this study, we document the use and recognition of complementary contact calls in Spix’s disc-winged bat (Thyroptera tricolor), a species known to form very stable social groups despite using an extremely ephemeral roosting resource. This bat uses 2 sets of calls: “inquiry,” which are emitted by flying bats that are seeking roosts or group mates, and “response,” which are produced in reply to an inquiry call by individuals that have already located a roost. Here, we test if bats are capable of discriminating between the inquiry and response calls of group and nongroup mates using playback experiments. Results show that flying bats can discriminate between the inquiry and response calls emitted by group and nongroup members and can maintain contact preferentially with the former. Roosting bats, however, exhibited no preference for group over nongroup members and thus responded indiscriminately. We argue that differences in how individuals respond to calls from group and nongroup members may be partly attributed to the costs associated with flight and the potential benefits of recruiting roost mates.Ítem A ClC Chloride Channel Homolog and Ornithine-Containing Membrane Lipids of Rhizobium tropici CIAT899 Are Involved in Symbiotic Efficiency and Acid Tolerance(2005) Rojas Jiménez, Keilor Osvaldo; Sohlenkamp, Christian; Geiger, Otto; Martínez Romero, Esperanza; Werner, Dietrich; Vinuesa, PabloRhizobium tropici CIAT899 is highly tolerant to several environmental stresses and is a good competitor for nodule occupancy of common bean plants in acid soils. Random transposon mutagenesis was performed to identify novel genes of this strain involved in symbiosis and stress tolerance. Here, we present a genetic analysis of the locus disrupted by the Tn5 insertion in mutant 899-PV9, which lead to the discovery of sycA, a homolog of the ClC family of chloride channels and Cl-/H+ exchange transporters. A nonpolar deletion in this gene caused serious deficiencies in nodule development, nodulation competitiveness, and N2 fixation on Phaseolus vulgaris plants, probably due to its reduced ability to invade plant cells and to form stable symbiosomes, as judged by electron transmission microscopy. A second gene (olsC), found downstream of sycA, is homologous to aspartyl/asparaginyl β-hydroxylases and modifies two species of ornithine-containing lipids in vivo, presumably by hydroxylation at a still-unknown position. A mutant carrying a nonpolar deletion in olsC is symbiotically defective, whereas overexpressed OlsC in the complemented strain provokes an acid-sensitive phenotype. This is the first report of a ClC homolog being essential for the establishment of a fully developed N2-fixing root nodule symbiosis and of a putative β-hydroxylase that modifies ornithine-containing membrane lipids of R. tropici CIAT899, which, in turn, are contributing to symbiotic performance and acid tolerance.Ítem A Comparison of four Methods to Evaluate the Butterfly Abundance. Using a Tropical Community(Journal of the Lepidopterists' Society 45(3), 1991, 241-243, 1991-03-18) Monge Nájera, Julián; Nielsen Muñoz, VanessaIn recent years. several transect methods to evaluate the abundance of butterflies have been proposed (Pollard, E. 1977, Biol. Conserv. 12:115—134; Feltwell, 3. 1982. Proc. Trans. Br. Entomol. Nat. Hist. Soc. 15:17—24). but to our knowledge there has been no attempt to compare experimentally their usefulness in relation to the availability of time and resources. Herein, we present the results of an experiment in which modifications of four of those methods were applied, simultaneously, to a community of neotropical butterfliesÍtem A comparison of Monstera deliciosa and M. tacanaensis, with comments on Monstera section Tornelia (Araceae)(2020) Cedeño Fonseca, Marco Vinicio; Díaz Jiménez, Pedro; Zuluaga Trochez, Alejandro; Blanco Coto, Mario AlbertoMonstera deliciosa, one of the most commonly cultivated aroids, is a morphologically variable species and has traditionally been considered native to southern Mexico, Guatemala, Costa Rica and Panama. We demonstrate that M. tacanaensis, which naturally occurs in those four countries and has been considered a synonym of M. deliciosa, is a closely related but different species. The natural range of M. deliciosa is restricted to southern Mexico and Guatemala. The name M. borsigiana is a synonym of M. deliciosa, representing one of its variations. The name Tornelia fragrans (another synonym of M. deliciosa) is lectotypified. A taxonomic history of Monstera section Tornelia (of which both M. deliciosa and M. tacanaensis are members) is presented; we also include M. maderaverde of Honduras in this section. Detailed descriptions and illustrations of M. deliciosa and M. tacanaensis are provided. The seeds of M. tacanaensis are extruded from the fruit at maturity, a phenomenon first reported here for the genus.Ítem A correction to the Lepanthes guatemalensis group (Orchidaceae: Pleurothallidinae) in Costa Rica, with a new species(2021) Pupulin, FrancoThe true Lepanthes edwardsii is first recorded for the flora of Costa Rica, described and illustrated on the basis of a Costa Rican voucher. The taxon previously recorded under that name is described as new to science as Lepanthes bogariniana; it is closely related to L. edwardsii, L. durikäensis, and L. viquezii, but can be distinguished by the narrowly elliptic lateral sepals, the tails straight to curved inward, the lobes of the petals with rounded apices, the blades of the lip straight and not bent towards the lateral sepals, and the yellowish-white column.Ítem A decade of submersible observations revealed temporal trends in elasmobranchs in a remote island of the Eastern Tropical Pacific Ocean(2024) Espinoza Mendiola, Mario; Quesada Pérez, Fabio; Madrigal Mora, Sergio; Naranjo Elizondo, Beatriz; Clarke, Tayler McLellan; Cortes Núñez, JorgeNo-take marine protected areas (MPAs) can mitigate the effects of overfishing, climate change and habitat degradation, which are leading causes of an unprecedented global biodiversity crisis. However, assessing the effectiveness of MPAs, especially in remote oceanic islands, can be logistically challenging and often restricted to relatively shallow and accessible environments. Here, we used a long-term dataset (2010-2019) collected by the DeepSee submersible of the Undersea Hunter Group that operates in Isla del Coco National Park, Costa Rica, to (1) determine the frequency of occurrence of elasmobranch species at two depth intervals (50-100 m; 300-400 m), and (2) investigate temporal trends in the occurrence of common elasmobranch species between 2010 and 2019, as well as potential drivers of the observed changes. Overall, we observed 17 elasmobranch species, 15 of which were recorded on shallow dives (50-100 m) and 11 on deep dives (300-400 m). We found a decreasing trend in the probability of occurrence of Carcharhinus falciformis over time (2010-2019), while other species (e.g. Taeniurops meyeni, Sphyrna lewini, Carcharhinus galapagensis, Triaenodon obesus, and Galeocerdo cuvier) showed an increasing trend. Our study suggests that some species like S. lewini may be shifting their distributions towards deeper waters in response to ocean warming but may also be sensitive to low oxygen levels at greater depths. These findings highlight the need for regional 3D environmental information and long-term deepwater surveys to understand the extent of shark and ray population declines in the ETP and other regions, as most fishery-independent surveys from data-poor countries have been limited to relatively shallow waters.Ítem A distinctive oral phenotype points to FAM20A mutations not identified by Sanger sequencing(2015-10-04) Poulter, James A.; Smith, Claire E. L.; Murillo Knudsen, Gina; Silva de la Fuente, Sandra Maria; Feather, Sally; Howell Ramírez, Marianella; Crinnion, Laura; Bonthron, David; Carr, Ian M.; Watson, Christopher M.; Inglehearn, Chris F.; Mighell, Alan J.Biallelic FAM20A mutations cause two conditions where Amelogenesis Imperfecta (AI) is the presenting feature: Amelogenesis Imperfecta and Gingival Fibromatosis Syndrome; and Enamel Renal Syndrome. A distinctive oral phenotype is shared in both conditions. On Sanger sequencing of FAM20A in cases with that phenotype, we identified two probands with single, likely pathogenic heterozygous mutations. Given the recessive inheritance pattern seen inall previous FAM20A mutation-positive families and the potential for renal disease, further screening was carried out to look for a second pathogenic allele. Reverse transcriptase-PCR on cDNA was used to determine transcript levels. CNVseq was used to screen for genomic insertions and deletions. In one family, FAM20AcDNA screening revealed only a single mutated FAM20A allele with the wild-type allele not transcribed. In the second family, CNV detection by whole genome sequencing (CNVseq) revealed a heterozygous 54.7 kb duplication encompassing exons 1 to 4 of FAM20A. This study confirms the link between biallelic FAM20A mutations and the characteristic oral phenotype. It highlights for the first time examples of FAM20A mutations missed by the most commonly used mutation screening techniques. This information informed renal assessment and ongoing clinical care.Ítem A genome‐wide quantitative trait locus (QTL) linkage scan of NEO personality factors in Latino families segregating bipolar disorder(2017) Dae Lee, Byung; González, Suzanne; Villa, Erika; Camarillo, Cynthia; Rodriguez, Marco; Shugart, Yin Yao; Guo, Wei; Flores, Deborah; Jerez, Álvaro; Raventós Vorst, Henriette; Ontiveros Sánchez de la Barquera, Jose Alfonso; Nicolini Sánchez, José Humberto; Escamilla, MichaelPersonality traits have been suggested as potential endophenotypes for Bipolar Disorder (BP), as they can be quantitatively measured and show correlations with BP. The present study utilized data from 2,745 individuals from 686 extended pedigrees originally ascertained for having multiplex cases of BP (963 cases of BPI or schizoaffective BP). Subjects were assessed with the NEO Personality Inventory, Revised (NEO PI‐R) and genotyped using the Illumina HumanLinkage‐24 Bead Chip, with an average genetic coverage of 0.67 cM. Two point linkage scores were calculated for each trait as a quantitative variable using SOLAR (Sequential Oligogenic Linkage Analysis Routines). Suggestive evidence for linkage was found for neuroticism at 1q32.1 (LOD = 2.52), 6q23.3 (2.32), 16p12 (2.79), extraversion at 4p15.3 (2.33), agreeableness at 4q31.1 (2.37), 5q34 (2.80), 7q31.1 (2.56), 16q22 (2.52), and conscientiousness at 4q31.1 (2.50). Each of the above traits have been shown to be correlated with the broad BP phenotype in this same sample. In addition, for the trait of openness, we found significant evidence of linkage to chromosome 3p24.3 (rs336610, LOD = 4.75) and suggestive evidence at 1q43 (2.74), 5q35.1 (3.03), 11q14.3 (2.61), 11q21 (2.30), and 19q13.1 (2.52). These findings support previous linkage findings of the openness trait to chromosome 19q13 and the agreeableness trait to 4q31 and identify a number of new loci for personality endophenotypes related to bipolar disorder.Ítem A High-Throughput Screen Identifies a New Natural Product with Broad-Spectrum Antibacterial Activity(2012) Ymele Leki, Patrick; Cao, Shugeng; Sharp, Jared ; Lambert, Kathleen G.; McAdam, Alexander J.; Husson, Robert N.; Tamayo Castillo, Giselle ; Clardy, Jon; Watnick, Paula I.Due to the inexorable invasion of our hospitals and communities by drug-resistant bacteria, there is a pressing need for novel antibacterial agents. Here we report the development of a sensitive and robust but low-tech and inexpensive high-throughput metabolic screen for novel antibiotics. This screen is based on a colorimetric assay of pH that identifies inhibitors of bacterial sugar fermentation. After validation of the method, we screened over 39,000 crude extracts derived from organisms that grow in the diverse ecosystems of Costa Rica and identified 49 with reproducible antibacterial effects. An extract from an endophytic fungus was further characterized, and this led to the discovery of three novel natural products. One of these, which we named mirandamycin, has broad-spectrum antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Vibrio cholerae, methicillin-resistant Staphylococcus aureus, and Mycobacterium tuberculosis. This demonstrates the power of simple high throughput screens for rapid identification of new antibacterial agents from environmental samples.Ítem A just overtime discovery: another new species of Echinosepala (Orchidaceae) from Costa Rica(2022-08-13) Pupulin, Franco; Álvarez Alcázar, Leonardo; Bogarín Chaves, Diego GerardoEchinosepala truncata is described as new to science and illustrated from the holotype. It is compared with E. tomentosa, from which it differs by the sparsely lanate ovary, the narrowly obovate, apically rounded synsepal, the spathulate, apically and basally rounded petals, and the rectangular, apically truncate lip. The phylogenetic relationships of the new species could be hypothesized based on a shared set of morphological characters and geographic distribution.Ítem A Mesoamerican origin of cherimoya (Annona cherimola Mill.): Implications for the conservation of plant genetic resources(2017) Larranaga González, Nerea; Albertazzi Castro, Federico José; Fontecha Sandoval, Gustavo Adolfo; Palmieri Santisteban, Margarita; Rainer, Heimo; van Zonneveld, Maarten; Hormaza Urroz, IñakiKnowledge on the structure and distribution of genetic diversity is a key aspect to plan and execute an efficient conservation and utilization of the genetic resources of any crop as well as for determining historical demographic inferences. In this work, a large data set of 1,765 accessions of cherimoya (Annona cherimola Mill, Annonaceae), an underutilized fruit tree crop native to the Neotropics and used as a food source by pre‐Columbian cultures, was collected from six different countries across the American continent and amplified with nine highly informative microsatellite markers. The structure analyses, fine representation of the genetic diversity and an ABC approach suggest a Mesoamerican origin of the crop, contrary to previous reports, with clear implications for the dispersion of plant germplasm between Central and South America in pre‐Columbian times. These results together with the potential distribution of the species in a climatic change context using two different climate models provide new insights for the history and conservation of extant genetic resources of cherimoya that can be applied to other currently underutilized woody perennial crops.Ítem A metabolomic platform to identify and quantify polyphenols in coffee and related species using liquid chromatography mass spectrometry(2023) Castro Moretti, Fernanda R.; Cocuron, Jean Christophe; Castillo González, Humberto; Escudero Leyva, Efraín; Chaverri Echandi, Priscila; Guerreiro Filho, Oliveiro; Slot, Jason C.; Alonso, Ana PaulaIntroduction: Products of plant secondary metabolism, such as phenolic compounds, flavonoids, alkaloids, and hormones, play an important role in plant growth, development, stress resistance. The plant family Rubiaceae is extremely diverse and abundant in Central America and contains several economically important genera, e.g. Coffea and other medicinal plants. These are known for the production of bioactive polyphenols (e.g. caffeine and quinine), which have had major impacts on human society. The overall goal of this study was to develop a high-throughput workflow to identify and quantify plant polyphenols. Methods: First, a method was optimized to extract over 40 families of phytochemicals. Then, a high-throughput metabolomic platform has been developed to identify and quantify 184 polyphenols in 15 min. Results: The current metabolomics study of secondary metabolites was conducted on leaves from one commercial coffee variety and two wild species that also belong to the Rubiaceae family. Global profiling was performed using liquid chromatography high-resolution time-of-flight mass spectrometry. Features whose abundance was significantly different between coffee species were discriminated using statistical analysis and annotated using spectral databases. The identified features were validated by commercially available standards using our newly developed liquid chromatography tandem mass spectrometry method. Discussion: Caffeine, trigonelline and theobromine were highly abundant in coffee leaves, as expected. Interestingly, wild Rubiaceae leaves had a higher diversity of phytochemicals in comparison to commercial coffee: defenserelated molecules, such as phenylpropanoids (e.g., cinnamic acid), the terpenoid gibberellic acid, and the monolignol sinapaldehyde were found more abundantly in wild Rubiaceae leaves.Ítem A methane sink in the Central American high elevation páramo: Topographic, soil moisture and vegetation effects(2020) Chai, Leanne L.; Hernandez Ramirez, Guillermo; Hik, David S.; Barrio, Isabel C.; Frost, Carol M.; Chinchilla Soto, Isabel Cristina; Esquivel Hernández, GermainMethane (CH4) is a strong greenhouse gas with a global warming potential 23 times larger than that of carbon dioxide. Characterizing ecosystems as either sources or sinks for methane and their magnitudes informs on biosphere contributions to the global CH4 budget and to warming of the atmosphere. We quantified methane fluxes for the first time in a neotropical alpine páramo (Valle de Los Conejos, Chirripó Massif, Costa Rica) and examined the relationships of these fluxes with topography, soil moisture and vegetation, during the transition from dry to rainy season. Using closed chambers and laser spectroscopy, we measured soil CH4 and CO2 fluxes across a field site encompassing: a grassy plain as well as a plain, a gentle slope and a plateau dominated by a dwarf bamboo (Chusquea subtessellata Hitchcock). We found that the páramo landscape acts as a sink for CH4 [−53.1 ± 29.6 (mean ± SE) µg C m−2 hr−1]. Of the four field areas, the grassy plain was on average the strongest CH4 sink, likely because this soil profile had no drainage restrictions and was well aerated. By contrast, in the slope and plateau, a heavily-consolidated subsurface layer was shown to perch water, increasing surface soil moisture and limiting CH4 uptake. Conversely, in certain parts of the plain, where Chusquea grew vigorously in discrete, tall patches, we found intense CH4 uptake beneath these patches. Within the Chusquea plain, these hot spots of CH4 uptake localized under the tall Chusquea had double the uptake rates than outside these patches, with even greater uptake than the average in the grassy plain. Our results show that CH4 uptake in the páramo is driven by moisture interacting with impeding soil layers, vegetation and topography.Ítem A microbial consortium from a biomixture swiftly degrades high concentrations of carbofuran in fluidized-bed reactors(2016) Castro Gutiérrez, Víctor Manuel; Masís Mora, Mario Alberto; Caminal, Glòria; Vicent, Teresa; Carazo Rojas, Elizabeth; Mora López, Marielos; Rodríguez Rodríguez, Carlos E.An on-farm biopurification system (BPS) biomixture, with proven capacity to degrade carbofuran (CBF) was used as inoculum for a selective-enrichment process to obtain a bacterial consortium capable of using CBF as a sole source of carbon. Bacterial strains that comprise the consortium were identified as members of the genera Cupriavidus, Achromobacter and Pseudomonas. The consortium was tested in batch bioreactors, with initial CBF concentrations ranging from 50 to 200 mg L−1, in which complete degradation was attained in 16–17 h. Continuous operation of the bioreactor was optimized to achieve conditions of complete removal of up to 100 mg L−1 of CBF at a HRT of 23 h by the microbial consortium. Cross-degradation assays showed that the consortium was also capable of degrading high concentrations of other carbamates such as aldicarb, methiocarb and methomyl in batch bioreactors. The use of this consortium for the treatment of CBF and other carbamates at reactor scale represents a potential approach for the removal of these pesticides from agricultural wastewater, as an alternative to BPS.Ítem A molecular study of Neophyllaphis varicolor (Hemiptera, Aphididae) in Costa Rica(2019-07) Zúñiga Centeno, Adonay; Sandoval Carvajal, Izayana; Montero Astúa, Mauricio; Villalobos Muller, William; Quốc, Nguyễn Bảo; Pérez Hidalgo, NicolásThe genus Neophyllaphis (Takahashi) (Aphididae: Neophyllaphidinae) is composed of 18 species; however, in the Americas only nine species have been reported previously. A new species, Neophyllaphis varicolor Miller & Halbert, was described in 2014 in USA. Colonies resembling those of this new species have been observed in Costa Rica on Podocarpus spp. In order to determine if N. varicolor is also present in Costa Rica, we sampled Neophyllaphis colonies from Podocarpus falcatus and P. chinensis. Additionally, we sampled individuals from Podocarpus sp. in Spain and Vietnam. DNA of each sample was extracted and used to amplify and sequence the cytochrome c oxidase subunit I (COI) and elongation factor I (EF-1α) partial regions. According to morphological characteristics, sequences comparisons done in GenBank and BOLD, and phylogenetic analyses, the colonies collected from Podocarpus spp. in Costa Rica and the colony from Vietnam corresponded to the species N. varicolor. To the best of our knowledge this is the first report of the presence of N. varicolor in Central America and Vietnam.Ítem A multi-locus molecular phylogeny for Australia’s iconic Jacky Dragon (Agamidae: Amphibolurus muricatus): Phylogeographic structure along the Great Dividing Range of south-eastern Australia(2014) Pepper, Mitzy; Barquero Arroyo, Marco David; Whiting, Martin J.; Keogh, J. ScottJacky dragons (Amphibolurus muricatus) are ubiquitous in south-eastern Australia and were one of the first Australian reptiles to be formally described. Because they are so common, Jacky dragons are widely used as a model system for research in evolutionary biology and ecology. In addition, their distribution along the Great Dividing Range of eastern Australia provides an opportunity to examine the influence of past biogeographical processes, particularly the expansion and contraction of forest habitats, on the diversification of this iconic agamid lizard. We generated sequence data for two mitochondrial and three nuclear DNA loci (4251base pairs) for 62 Jacky dragons sampled from throughout their distribution. Phylogenetic analyses based on maximum likelihood and Bayesian species-tree methods revealed five geographically structured clades separated by up to 6% mitochondrial and 0.7% nuclear sequence divergence. We also quantified body proportion variation within and between these genetic clades for more than 500 specimens and found no evidence of any significant differentiation in body proportions across their range. Based on body proportion homogeneity and lack of resolution in the nuclear loci, we do not support taxonomic recognition of any of the mitochondrial clades. Instead, A. muricatus is best thought of as a single species with phylogeographic structure. The genetic patterns observed in the Jacky dragon are consistent with fragmented populations reduced to multiple refugia during cold, arid phases when forested habitats were greatly restricted. Consequently, the inferred biogeographic barriers for this taxon appear to be in line with lowland breaks in the mountain ranges. Our results are congruent with studies of other reptiles, frogs, mammals, birds and invertebrates, and together highlight the overarching effects of widespread climatic and habitat fluctuations along the Great Dividing Range since the Pliocene.Ítem A new and unusual species of Dichaea (Orchidaceae: Zygopetalinae) from Costa Rica(2020) Pupulin, Franco; Karremans Lok, Adam PhilipA new and florally unusual species of the genus Dichaea is described and illustrated from Costa Rica, where it is apparently endemic, and its relationships are discussed. Dichaea auriculata is compared with the group of species close to D. graminoides, from which it can be distinguished by the lip with a long isthmus, provided with two rounded auricles at the base, instead of the sessile lip typical of the group. It is also compared with another Costa Rican endemic in the same complex, D. gracillima, from which it can be distinguished by the autogamous, mostly cleistogamous, flowers, the 3-lobed lip with rounded basal lobes, the high keel along the lip isthmus, and the bifid ligule of the column. Notes on the habitat and the ecology of the new species are provided.Ítem A new Brachionidium (Orchidaceae: Pleurothallidinae) from the first botanical expedition to the Volcán Cacho Negro, Costa Rica(2016-12) Bogarín Chaves, Diego Gerardo; Karremans Lok, Adam PhilipA new species of Brachionidium from Costa Rica is described and illustrated. Brachionidium cornu-nigricum, from the Volcán Cacho Negro, a remote, previously unexplored location in Costa Rica, is most similar to B. filamentosum. It differs in the white sepals, short-acuminate sepals and petals up to 1 cm long, the triangular, unlobed lip, the oblong glabrous callus provided with two small basal lobes, and the eight pollinia.