Revista de Biología Tropical / International Journal of Tropical Biology and Conservation, es una revista de acceso abierto completo de la Universidad de Costa Rica centrada en la biología tropical y la conservación. Todos los números, desde 1953 hasta la actualidad, están disponibles para su descarga gratuita. aquí. NUESTRO ENFOQUE (Objetivo) Nuestra revista publica artículos científicos que aumentan nuestra comprensión de la biología, la conservación y las ciencias biomédicas de la vida en los trópicos. Los criterios de selección son la cantidad y calidad de la nueva información y su interés potencial tanto para el público en general como para los especialistas. Los ecosistemas estudiados, o al menos los organismos, deben ser tropicales. COBERTURA TEMÁTICA Números regulares Damos preferencia a artículos de fondo que incluyen preguntas de estudio comprobables, por ejemplo, estudios con un diseño experimental que evalúe factores que influyen en variables biológicas, o estudios que explican los mecanismos subyacentes a fenómenos biológicos o biomédicos como, por ejemplo, el comportamiento o la fisiología. Los estudios de campo deben presentar patrones temporales o espaciales. También damos la bienvenida a estudios sistemáticos o filogenéticos por encima del nivel de especies, metanálisis y estudios bibliométricos que examinan críticamente lo que se conoce y lo que queda por hacer en cualquier campo de la biología tropical. Los artículos de revisión se publican en su mayoría por invitación del Consejo Editorial a autoridades reconocidas. Otros especialistas interesados en enviar una revisión primero deben enviar un esquema de manuscrito titulado al correo biologia.tropical@ucr.ac.cr. Las propuestas aceptadas reciben la misma evaluación que los manuscritos regulares. Todas las revisiones y metanálisis deben identificar y llenar los vacíos en el conocimiento, presentar avances metodológicos y proponer futuras direcciones de investigación. Nota sobre datos antiguos: Si su trabajo se basa en datos antiguos, recomendamos compararlos con datos más recientes, o usarlos como parte de meta-análisis, para darles mayor valor. Los estudios basados en datos recopilados hace más de seis años deben incluir una justificación de por qué siguen siendo de interés y, en el caso de estudios de campo, deben presentar patrones espaciales o tendencias temporales de importancia histórica. El Comité Editorial evalúa la validez de los métodos y la relevancia de los resultados antes de enviar el manuscrito a revisión. La revista ahora cuenta con un número al año (publicación continua del 1 de enero al 31 de diciembre) y publica los artículos la misma semana en la que se tiene disponible una versión editada. Hasta 2021 publico cuatro números regulares por año: número 1 (enero-marzo), número 2 (abril-junio), número 3 (julio-septiembre) y número 4 (octubre-diciembre). No publicamos notas; comunicaciones cortas; listas de especies; nueva especie única; extensiones de rango; nuevos registros y otros estudios preliminares o breves; o informes técnicos altamente especializados basados en protocolos (por ejemplo, estudios agrícolas, forestales, bioquímicos, microbiológicos, acuícolas, pesqueros o similares que solo aplican técnicas bien conocidas a casos particulares de interés local). NÚMEROS ESPECIALES Los números especiales financiados por organizaciones de investigación se aceptan después de la aprobación del Comité Editorial. Pueden contener una diversidad de tipos de informes, incluidos artículos breves, nuevos registros, nuevas descripciones de especies, listas de verificación, informes técnicos, etc. Para publicar un número especial, comuníquese con biologia.tropical@ucr.ac.cr para obtener una estimación de costos. PÚBLICO META Personas investigadoras con interés en el estudio de todos los campos de la biología tropical. PORQUÉ PUBLICAR EN LA REVISTA DE BIOLOGÍA TROPICAL? Totalmente indexada: Revista de Biología Tropical está incluida en Science Citation Index Expanded, REDIB Journals Ranking, Current Contents, Google Scholar, Biological Abstracts y alrededor de 50 otros índices internacionales. Rápida decisión y publicación (7 días para la primera decisión, 5-7 meses para aceptación definitiva, 6-8 meses desde el envío hasta la publicación). Razonable: utilizamos un sistema de doble ciego para una evaluación justa de los manuscritos. Alto impacto, no solo por su índice de citas, sino también porque es muy leído en países con la mayor biodiversidad tropical, lo que garantiza que su artículo tendrá el mayor impacto en la conservación de la biodiversidad tropical. Factor de impacto de Web of Science de 0.6. Factor de impacto en SJR de 0.28 (Q2). Un trato personalizado por parte de nuestro dedicado personal. Juntas editoriales y científicas de clase mundial. Acceso abierto: Todos los artículos, desde el primer número en 1953 hasta el presente, están disponibles gratuitamente en línea (Archivos), por lo que es más probable que sean citados que los artículos detrás de muros de pago. PUBLICACIÓN GRATUITA: Cada artículo recibe 10 páginas de espacio libre en formato PDF, que es suficiente para la mayoría de los artículos científicos. Se pueden publicar páginas adicionales diagramadas en el pdf a $50 cada una. Material complementario como textos adicionales, figuras, tablas, gráficos y bases de datos con un costo de $60. Póngase en contacto con biologia.tropical@ucr.ac.cr para obtener más información. OAI-PMH: https://revistas.ucr.ac.cr/index.php/RBT/oai
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Molecular determination of Helicobacter pylori and detection of beta-lactamases in clinical isolates from patients in Antioquia-Colombia
Introduction: Helicobacter pylori exhibit variations in antibiotic resistance in America and Colombia. Despite the use of various treatment regimens containing amoxicillin in the department of Antioquia, Colombia, as well as in several countries across the continent, the pattern of genotypic and phenotypic susceptibility to this antibiotic remains unknown. Objective: To determine the frequency of H. pylori infection by detecting the ureA gene and amoxicillin susceptibility through beta-lactamases in H. pylori isolates from patients with gastroduodenal diseases in Antioquia-Colombia. Methods: Cross-sectional analytical study with 179 patients attending endoscopy units of seven healthcare institutions. Sociodemographic and risk factor data were collected. Moreover, biopsies from the antrum and body were taken for microbiological isolation and molecular detection of H. pylori. The sociodemographic data were assessed through frequency analysis and bivariate statistics. DNA obtained from the biopsies was amplified by PCR for the ureA gene, and beta-lactamase production was evaluated using the nitrocefin test as well as the amplification of the TEM and SHV genes. Results: It was found that 61 % (109 / 179) of patients tested positive for H. pylori; out of 84 isolates obtained by culture, none tested positive for the nitrocefin test. Significant differences were found in socioeconomic status, healthcare system, and geographical location in patients positive for the ureA gene. Two patients tested positive for molecular detection of beta-lactamases from biopsies; however, SHV and TEM genes were not found in any isolate. Conclusions: The frequency of H. pylori for ureA-gene detection is higher than previous studies and similar to other reports in other Colombian regions; consequently, this will become a good diagnostic test in the country. Finally, none of the H. pylori isolates tested positive for beta-lactamases TEM and SHV.
Copyright (c) 2025 Revista de Biología Tropical http://creativecommons.org/licenses/by/4.0
Epiphytic macrolichen as indicators of environmental changes in a montane forest of Panama
Introduction: Corticolous lichens are organisms that respond to habitat modifications, which is why they are considered model organisms to evaluate environmental changes in different ecosystems. Objectives: To determine the species richness and community composition of corticolous macro lichens in montane forests and forest remnants. In addition, the effect of microclimatic factors in three areas with different degrees of light intensity and density of arboreous vegetation on the species distribution of recorded diversity was evaluated. Methods: The study was conducted in the Volcan Baru National Park, Panama. Three areas with different forest densities and host tree species, Comarostaphylis arbutoides and Quercus spp., were chosen, considering a total of 60 trees, 10 of each species in each area. The canopy's opening close to the host trees and its diameter at breast height were recorded. Linear models and multivariate analysis was used to determine changes in species richness and composition of epiphytic macro lichens. Results: The characteristics of the host trees (e.g. host species and area) conditioned the species richness, while the communities were limited by microclimatic changes (e.g. light) in different areas. Conclusion: The macro lichens communities analyzed responded to changes related to the host tree species and the microclimate, so they can be considered indicators of ecological continuity in tropical montane forests.
communities; corticolous; lichens; light, Lobariaceae; Parmeliaceae; phorophyte; zone
Status of the coral formations of Bajo Nuevo Reef Complex, Western Caribbean, Colombia
Introduction: Although many reefs have been disturbed by the combined effects of climatic and non-climatic stressors, there still are regions largely free from direct human pressures such as runoff, pollution, and maritime traffic due to their geographic remoteness. This suggests that they are replicas of “pristine reefs”, that allow the investigation of relationships between reef communities and their environment. Objective: To evaluate the status of the coral formations of Bajo Nuevo, Seaflower Biosphere Reserve. Methods: The coral health and the relative cover of reef-building organisms and of their main competitors were evaluated. In every station (11), ten photo quadrants of 0.25 m2 were evaluated along a 10 m tape measure combined, along with ~3 min videos. Results: 32 coral species were recorded, 30 of them Scleractinia and two of hydrocorals, with the highest richness in the reef lagoon. In 2021, the reefs in Bajo Nuevo were dominated by non-reef-building organisms (61.7 ± 0.10 %), the building species represented only 23.9 ± 0.10 %; 3.2 ± 0.03 % was coral skeleton with recent and transitional death less than 15 days old. Signs of diseases affected three genera, 13 species and 23.5 % of the colonies evaluated, of which 84.9 % showed one of the four signs related to the stony coral tissue loss disease. Conclusions: With previous expeditions (2010-2011) as a reference, this reef complex registered in 2021 a drop in the cover of hard corals and calcareous algae, and coral richness; an increase in the cover of non-reef-building organisms, with a high prevalence of signs of unhealthiness associated with different coral diseases. This confirms that these reefs are in danger (EN), as suggested by the red list of marine and coastal ecosystems of Colombia.
Diversity and cultural value of the mastofauna associated with coffee plantations in Oaxaca, Mexico
Introduction: The expansion of conventional agriculture has caused the loss of natural habitats for the fauna, but the coffee agroecosystems of Oaxaca can provide an alternative habitat for mammals, which is associated with the cultural value that human communities assign to them. Objective: To assess the diversity and cultural value of medium and large mammals associated with the coffee plantation, and what they represent for the inhabitants of San Gabriel Mixtepec, Oaxaca, Mexico. Method: A mixed method was used. For the diversity analysis, the mammal species were identified through camera traps. To determine the Cultural Importance Index (IIC), semi-structured interviews and participatory workshops were carried out with the residents, who also helped to identify the different uses of the medium and large mammals. Results: A total of 26 species grouped into seven orders, 14 families, and 23 genera were recorded. Alpha diversity was greater in the dry season than in the wet season. Some species were detected in only one of the two seasons. Six hundred and thirty-nine records of cultural uses of mammals were obtained; use as food was the most mentioned. Twelve types of uses were identified. The species with the greatest cultural importance were Odocoileus virginianus (IIC = 0.92), with 11 uses, followed by Dasypus novemcinctus (IIC = 0.61), with 10 uses, Conepatus leuconotus (IIC = 0.60), with eight uses and Didelphis virginiana (IIC = 0.52), with 11 uses. Conclusion: The results show the importance that human residents assign to mammals associated with coffee agroecosystems, both for their use for subsistence and to complement the family economy. Furthermore, the residents themselves emphasize the importance of their traditional knowledge and the need to adopt sustainable management practices for the mastofauna, because they recognize the importance it has in the community and the benefits it can have on the environment.
mammals; Cultural Importance Index (IIC); coffee; agroecology; biocultural
Diversity and vertical distribution of epiphytic orchids and bromeliads in two contrasting forests from Northeast Andes of Colombia
Introduction: Functional traits analysis allows an understanding of the mechanisms that structure plant communities epiphytes. The distribution of taxonomic and functional epiphyte diversity along vertical gradients is a key tool to track epiphytes’ response to environmental changes, especially in biodiversity hotspots, where a high number of endemic species are threatened. Objective: To relate the taxonomic and functional epiphyte diversity and their vertical distribution with forest structural variables of the Montane and Dry Forest ecosystems in the Colombian Andes. Methods: Epiphyte diversity in each study site was recorded in 35 random phorophytes. Alpha and functional diversity were compared for five vertical strata of the canopy (Z1-Z5) and related to forest structural and floristics variables such as tree richness, tree density, diameter at breast height (DBH), canopy height, crown area, and canopy openness. Results: The Montane Forest presented a greater diversity of epiphytes, mainly orchids, with Stelis angustifolia as the dominant species. In contrast, the Dry Forest presented a greater Bromeliad abundance, and Tillandsia recurvata was dominant. Montane forest epiphytes were represented by three functional groups: tank-bromeliads, shallow tank-bromeliads, and ramicauls-orchids, while in the Dry Forest shallow tank-bromeliads and nebulophyte-bromeliads. Positive correlations were found between epiphyte richness, abundance, and diversity with variables related to phorophyte size (DBH and crown area) in montane forest. There was also a different tendency on the preference for some strata between Orchids (Z2-Z3) and Bromeliads (Z3-Z4). Conclusion: Differences were found in the taxonomic and functional diversity of epiphytes between the two forests, where orchids and bromeliads often coexist in similar environments but are distributed in different habitats, resulting from adaptation to specific environmental conditions, which allows them to coexist in different niches within the ecosystem.
Andean forests; ecosystem functions; oak forest; phorophyte; Quercus humboldtii
Density, size and composition of howler monkeys, Alouatta palliata (Atelidae) and white-faced monkeys, Cebus imitator (Cebidae) in dry forest and reduced canopy areas, Costa Rica
Introduction: The size, density, and composition of primate social groups are essential for understanding group dynamics and determining population management plans for primate conservation. Objective: To determine the size, density, and composition of howler monkeys (Alouatta palliata) and white-faced monkey (Cebus imitator) groups in dry forest environments and areas of reduced canopy in Palo Verde National Park, Costa Rica. Understanding how these species respond to different environments has important implications for conservation and reforestation efforts. Methods: Field sampling was carried out during February 2023 during the peak hours of primate activity (6:00-12:00 and 14:00-18:00). The individuals of both primate species were counted, recognizing the groups found in both types of environments (dry forest and reduced canopy areas). Results: Howler monkey group sizes were significantly larger in dry forests and at a higher percent of canopy cover. As for white-faced monkeys, a higher density was recorded in dry forests compared to the last census in 1987. Conclusion: Greater availability of resources (abundance of food and shelter sites) in closed environments favors the presence of a greater number of howler monkeys. Our analyses show that group size in this primate species depends on the type of environment. This study highlights the importance of long-term monitoring and studies of these parameters in wild primate groups.
conservation; management; primates, survey; Platyrrhini
Flora of high mountain tropical peatlands: threats and management measures, Talamanca Range, Costa Rica
Introduction: Tropical peatlands are highly fragile vegetal formations, especially vulnerable to anthropogenic impacts and changes in climatic conditions. Objective: To characterize the flora of the Talamanca peatlands, as well as identify their dynamics, threats, and impacts. Methods: The flora was analyzed in five peat bogs located in the Buenavista Massif, along the Inter-American Highway, at altitudes of 2 400 - 3 100 m, through field sampling. Subsequently, a Floristic Value Index (IVF) was designed to assess the state of conservation. Results: The floristic richness was determined in the peat bogs studied. A lower biological diversity was found in the three peatlands outside the state-protected natural spaces, suggesting the influence of the edge effect and agro-productive activities or their proximity to the Highway. In contrast, the Salsipuedes and Cerro Paramillo peatlands exhibited greater diversity, highlighting genera such as Blechnum, Puya, Chusquea, Myrsine and Vaccinium, in association with the bryophyte genus Sphagnum. A different floral composition was observed along the strip near the Inter-American Highway, characterized by species with lower water demand, especially genera such as Rubus and Pteridium, among others. Conclusion: From the identified floristic composition, the importance of peatlands as part of the mesoamerican hotspot ecosystems was determined, not only as repositories of biodiversity but also as sensitive indicators of human influence and environmental threats in the region associated with anthropic impact and climate change.
high-altitude peatlands; biodiversity; anthropogenic impact; tropical paramo; Mesoamerican hotspot
Effects of human disturbance on medium and large mammals in primary and secondary tropical forests in Southern Mexico
Introduction: In tropical forests, populations of medium and large mammals are being impacted by human activities. Understanding how species respond to land use conversion, fragmentation, and the encroachment of roads density and settlements is of conservation interest in highly biodiverse regions. Objetive: To assess the effect of human disturbance and environmental variables on trophic guilds of medium and large mammals in the tropical forests of the Sierra Negra-Mazateca in Southern Mexico. Methods: We characterized the landscape (land use and vegetation, number of fragments, and edge density) through supervised classification of Landsat 8 images. We recorded species using camera-trap stations and evaluated the relationship between the presence and relative abundance of species with human disturbance variables using zero-inflated regression models. Results: The landscape of the Sierra Negra-Mazateca is dominated by fragments of secondary forests (48.6 %) with a small proportion of primary forests (9.6 %). We found no differences in the overall relative abundance of species between primary and secondary forests, but differences were observed for omnivore and carnivore guilds. Human disturbances had a disparate effect among guilds, negatively affecting carnivores and positively herbivores. Conclusions: Secondary forests are refuges for tolerant species. Nevertheless, we emphasize the need to conserve primary forests to safeguard medium and large mammals, especially the carnivore guild. Extensive management in secondary forests is recommended to conserve remaining primary forests, alongside community awareness and empowerment for coexistence with wildlife.
carnivores; defaunation; human disturbance; landscape analyses; landsat; montane cloud forest; zero-inflated models
Growth, recruitment and life history parameters of fish in Andean reservoirs
Introduction: The formation of new anthromes such as reservoirs and dams to generate energy for human consumption, provides new environmental scenarios that condition the survival of the pre-existing fish species in the modified system. Objective: To estimate some of the main population attributes in relation to growth and recruitment discussed in the context of the life histories of the species analyzed for a high-Andean river system. Methods: Based on the historical sequence (2005-2017) for the seven species with the highest numerical record and frequency distributions, a typical population parameter estimation analysis was employed following the Growth Model proposed by von Bertalanffy (MCvB) and empirical equations to the respective complementary parameters. Results: A total of 28 651 frequency lengths were analyzed, finding that those species with rapid growth and lower longevity prefer artificial lacustrine environments, species with opportunistic life history strategies (Astyanax microlepis and Roeboides dayi) and with a bimodal recruitment pattern, while species with intermediate growth were seasonal (Brycon henni y Hemibrycon caucanus), registered in tributaries to the reservoir, and in equilibrium (Andinoacara latifrons, Chaetostoma thomsoni and Coptodon rendalli) mainly associated with rivers, reservoirs, and streams or transitional environments to reservoirs. Conclusion: The analysis of information on the population dynamics and live history of fish coexisting in a reservoir and its surrounding environments suggests a spatial segregation of fish species in response to a possible selection of their biological traits and other bioecological characteristics that sustain their local populations.
life history; von Bertalanffy; Porce river; recruitment; ecological filter.
Composition, structure and regeneration strategy of Campnosperma panamense (Anacardiaceae) swamp forests in Darien, Panama
Introduction: Orey swamp forests (Campnosperma panamense) are found on the Caribbean coast of Central America, from Nicaragua to Panama, and in the Pacific of Colombia to Northern Ecuador. In Panama, orey grows in monospecific stands or is the dominant species in inundated mixed forests, mainly along the coasts of Bocas del Toro province and Comarca Ngäbe-Buglé. The species was known to occur in Darien province, in the Pacific, although almost no information on its distribution and forest extension in the region existed. Objective: To describe the structure and floristics of orey forests in Darien, map their extension, and propose a model for their regeneration strategy. Methods: This work is part of a vegetation mapping project of the Matusagaratí complex of wetlands. It includes the use of drones, ground truthing, vegetation sampling through temporary plots, and general plant collecting. A supervised classification of a Landsat satellite image was performed to delimit the orey forest extension. To study the orey forest regeneration strategy, a digitalization of forest gaps in high resolution WorldView-2 and Planet Scope images over years was performed. Gap frequency and turnover time for forest stands were calculated. Results: Several monospecific orey mature forest patches were found in remote areas of the Matusagaratí complex of wetlands, for a total of 1 267 hectares. A description of the floristics and structure of orey forests in Darien is presented. A conceptual model of orey mature forest development and gap regeneration is proposed. Conclusions: Our knowledge of the floristic composition, structure and distribution of orey forests in the Republic of Panama has increased. For the first time, a model about their regeneration strategy is proposed. These forests seem to be evolving to different formations. Finally, some hypotheses are proposed about how they might respond to changing environmental conditions.
Matusagaratí; complex of wetlands; swamp forests; orey; Darien; regeneration strategy
Examining functional diversity in two plant communities under ecological restoration in Farallones de Cali, Colombia
Introduction: Functional diversity is crucial in understanding species performance and monitoring ecological restoration processes. In Valle del Cauca, Colombia, where only a small percentage of tropical dry forest remains, ongoing ecological restoration efforts are vital. However, monitoring of restoration efforts is typically not conducted. Objective: To compare the functional diversity of two plant communities, restored two and eight years ago, in the Loma Larga reserve, Colombia. Methods: We assessed nine functional traits in the five most significant species of each community. The analysis included contrast tests for functional trait differences, as well as functional diversity indices. Results: The 8-year community displayed greater values for maximum height, diameter at breast height, and specific leaf area. Conversely, the 2-year community exhibited higher leaf thickness. Moreover, the 8-year community presented the highest values in the functional indices: richness, evenness, divergence, dispersion, and specialization. Conclusions: Ecological restoration had a positive impact on plant communities, as evidenced by increased functional diversity and structural complexity in the 8-year community compared to the 2-year community. This suggests that ecological succession processes advance significantly over time, leading to more resilient and functionally diverse communities. The analysis of functional traits stands out as an effective tool for monitoring the success of restoration and guiding future efforts in critically threatened ecosystems such as tropical dry forests.
The effect of macrophytes on the presence and population structure of the red swamp crayfish Procambarus clarkii (Decapoda: Cambaridae) in neotropical ecosystems
Introduction: The red swamp crayfish, Procambarus clarkii, is a crustacean species native to Mexico and the United States. It has been introduced around the world, often becoming established as an invasive exotic species. Since its introduction in 1985 in Colombia, no studies have been carried out to determine factors that influence the presence of the species in high mountain ecosystems. Objective: To evaluate the relationship over time between macrophytes and the different stages of development of P. clarkii in a tropical high Andean aquatic ecosystem. Methods: A new collection method called "macrophyte sweep" was standardized. This method ensured the collection of crayfish of all possible sizes, especially juveniles. Sampling was carried out bimonthly for seven months. The morphometry of P. clarkii was evaluated in three macrophytes: Juncus effusus, Ludwigia peruviana, and Polygonum punctatum. Results: A total of 778 individuals were collected, of which 365 were females, 344 males, and 69 sexually indeterminate. The total population density was 6.48 ind/m2. Most organisms were found on P. punctatum (71.9 %), followed by L. peruviana (17.7 %) and J. effusus (10.28 %). The largest and heaviest organisms were recorded in September in all three macrophytes, while the smallest were collected in July and May. P. clarkii exhibited a greater affinity for the macrophyte P. punctatum in its different developmental stages, possibly because it offers greater structural complexity in the submerged zone, providing shelter for juveniles and a food source for adults. Conclusions: Our results highlight that much of the colonization success of P. clarkii is due to the relationship between macrophytes and the development of different life stages in neotropical ecosystems.
The performance of mass testing strategies for COVID-19: a case study for Costa Rica
Introduction: In this article, we derive the behavior of four different mass testing strategies, grounded in guidelines and public health policies issued by the Costa Rican public healthcare system. Objective: To formally develop the changes of each studied mass testing strategy under different contexts related to people’s risk, costs of testing, and accessibility to alternative testing technologies. Methods: We take over a pre-classifier applied to individuals capable of partitioning suspected individuals into low-risk and high-risk groups. We consider the impact of three testing technologies: RT-qPCR, antigen-based testing, and saliva-based testing (RT-LAMP). When available, we introduced a category of essential workers. Results: Numerical simulation results confirm that strategies using only RT-qPCR tests cannot achieve sufficient stock capacity to provide efficient detection regardless of prevalence, sensitivity, or specificity. Strategies that harness the power of pooling and RT-LAMP either maximize stock capacity, detection efficiency, or both. Conclusions: Investing in data quality and classification accuracy can improve the odds of achieving pandemic control and mitigation. Future work will be focused on, based on our findings, constructing representative synthetic data through agent-based modeling and studying the properties of specific pre-classifiers under various scenarios.
mass testing; COVID-19 Costa Rica; RT-qPCR; antigen test; RT-LAMP; pooling; detection strategies
Demographic variations of the spotted snapper Lutjanus guttatus (Perciformes: Lutjanidae) along the Pacific coast of Costa Rica suggest the existence of two population units
Introduction: The spotted rose snapper Lutjanus guttatus is one of the commercially most important fish species in tropical and subtropical areas of the Eastern Tropical Pacific. In Costa Rica, L. guttatus is one of the main target species of the artisanal fishery; traditionally, its management has considered a single population that extends along the entire coastal zone. However, there is no evidence that there is only one population unit, which could affect the effective management of this valuable resource. Objective: Determine the population structure of L. guttatus caught on the Pacific coast of Costa Rica through demographic parameters. Methods: A total of 428 specimens, collected in different zones along the Pacific coast of Costa Rica were analyzed, including 190 males and 238 females. The size structure, total length-weight relationship, maturity stages, mean size at sexual maturity, age and growth were estimated, differentiating between the Northern, central, and Southern Pacific of Costa Rica. Results: Demographic variations were observed in size structure, total length-weight relationship, the average size of sexual maturity, and growth rates among the organisms caught in the three sampling regions. Conclusion: The demographic variations of L. guttatus in the different capture areas suggest the probable existence of two separate population units; the first corresponds to the Northern Pacific, and the second includes the central and Southern Pacific areas. The above has important implications for the management of the resource.
Motile macroinvertebrates and fishes sheltering in burrows with and without the Indo-Pacific Rock-boring Urchin Echinometra mathaei (Camarodonta: Echinometridae), at Mana Island, Fiji
Introduction: Sea urchins of the genus Echinometra are ecosystem engineers that burrow into lower intertidal and subtidal rocks, creating shelter for themselves and a variety of marine animals. Objective: To test the hypothesis that motile macroinvertebrates and fishes shelter proportionately more frequently in burrows with Echinometra mathaei, whose spines potentially offer additional protection, than in burrows without E. mathaei. Methods: We studied the motile macroinvertebrates and fishes sheltering in the burrows of the Indo-Pacific Rock-boring Urchin E. mathaei (Type C) at Mana Island, Fiji. Results: Burrows with E. mathaei averaged shorter in length than burrows without E. mathaei. We observed 42 motile macroinvertebrates of at least eight species and 49 fishes of at least eight species in burrows with E. mathaei (n = 1 127), and four motile macroinvertebrates of three species and one fish of one species in burrows lacking E. mathaei (n = 243). Motile macroinvertebrates occurred with statistically equal frequencies in burrows with E. mathaei (3.6 %) and in burrows without E. mathaei (2.5 %). Fishes occurred significantly more frequently in burrows with E. mathaei (4.3 %) than in burrows without E. mathaei (0.4 %). Conclusion: Fishes, but not motile macroinvertebrates, gain more protection from predators by sheltering in burrows with sea urchins, whose spines offer additional protection, than in burrows without sea urchins.
Structure of fish communities in relation to habitat in Matusagaratí Lagoon, Darién, Panama
Introduction: Matusagaratí lagoon is an ecosystem with diverse habitats and environmental conditions that determine the diversity and distribution of aquatic life. Despite hydraulic connectivity, aquatic habitats generated by this diversity of environmental conditions could determine the composition and structure of fish assemblages. Objective: To understand the structure of fish community in three of these habitats. Methods: Multi-habitat sampling was conducted between March 2022 and September 2023, covering periods of drought and flooding, at 29 sites using different fishing techniques. Results: 1 913 fish from 50 species and 27 families were collected in approximately 320 km2. Three fish assemblages were identified, each associated with a specific habitat. The river corridor of the Tuira River had the greatest diversity, followed by the tidal streams and lagoons. Conclusions: The analysis revealed notable differences between these habitats, with the river corridor dominated by peripheral species, while lagoons showed low diversity with generalized or hypoxia-adapted species. The presence of species such as Hoplosternum punctatum, Ageneiosus pardalis and Pimelodus punctatus in the wetland evidences the influence of the Choco region on Panama´s ichthyofauna. These findings could have important implications for the formulation of wetland conservation strategies.
freshwater fishes; peripheral fishes; Tuira river; Darien province
Protozoos and metazoos present in two wastewater treatment systems and their relationship with the Sludge Biotic Index
Introduction: Sludge Biotic Index (SBI) is one of the most used indices for the characterization of the community of microorganisms present in the activated sludge of wastewater treatment systems. However, this index takes into consideration only the density of the predominant functional groups of protozoa that inhabit this sludge. Objective: To evaluate whether the SBI value can be directly related to the number of protozoos and metazoos species found in the activated sludge of two wastewater treatment systems. Methods: This study was carried out on the wastewater generated by the San Vicente de Paul Hospital in Heredia Province, Costa Rica, during the months of February, March, and April 2022. Physicochemical, environmental, operational, and biological parameters were analyzed in a total of 36 samples from a Conventional activated sludge wastewater treatment system and from a Membrane Bioreactor (MBR) (n = 18 for each treatment system). Results: All the parameters evaluated are related to the abundance of microorganisms in the samples analyzed. The SBI value had an important effect on the number of organisms and can be related to the performance of the treatment system in terms of the percentage of Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) removal, especially for the MBR system. Conclusions: The SBI can be improved so its calculation not only considers functional groups but also includes genus and species of protozoos and metazoos present in the activated sludge. Which in turn would refine its bioindication potential by being more specific in terms of abundance, behavior and specific requirements of each species.
flocs; activated sludge; ciliates; amoebas; rotifers; nematodes
Presence of microplastics in macroinvertebrates of mangroves in the Colombian Pacific: are feeding behaviors determinant for its abundance?
Introduction: In mangroves, microplastics (MPs), (< 0.5 mm particles) penetrate deep into the sediments and can cause adverse effects on the species that consume them by accident, affecting their development, nutrition, and life quality in general. In Colombia, studies on plastic and microplastic pollution have been focused on the Caribbean coast and its consumption by fishes, however, the Pacific has been scarcely documented. Objective: To confirm the presence of MPs in mangrove organisms of two locations of Buenaventura Bay, Colombia, to characterize them, and to estimate their effect on trophic groups. Methods: Two species of cockles, Anadara similis and Anadara tuberculosa, and crab Goniopsis pulchra were selected. MPs were extracted, counted, and classified according to shape and color. Results: In total, 81 individuals were captured. We found MPs in 100 % of the organisms and transparent fragments were the most abundant (56.40 %). An average of 25.54 ± 23.8 particles/individual was found, and no differences were found between the cockles, but between each regarding G. pulchra. Conclusion: The different feeding behaviors could explain these differences; more generalist species would ingest a more significant amount of particles. This is the first approximation to studying MPs inside invertebrate organisms in the Colombian Pacific.
marine debris; filter feeders; cockles; Buenaventura Bay; mangrove crab
Population dynamics and morphometry of the crayfish Procambarus clarkii (Decapoda: Cambaridae) introduced in Central Mexico
Introduction: Procambarus clarkii is an invasive species introduced to central Mexico that threatens biodiversity. Objective: To analyze monthly, during an annual cycle, the demographic and morphometric changes of P. clarkii concerning environmental variation in a reservoir (Taxhimay, State of Mexico). Methods: Abundance, sex ratio, fecundity, and nutrition in females were determined using the hepatopancreatic (HSI) and gonadosomatic (GSI) indices. Results: The PCA showed that phycocyanin, chlorophyll a, and pH explained 80.7 % of the environmental variation and grouped the sample sites into October-February, March-April, May-July, and August-September. A total of 464 individuals were captured; 198 (43 %) were females, and 266 (57 %) were males, of which 26 were non-reproductive form II. Abundance was positively correlated with phycocyanin and chlorophyll a and negatively correlated with transparency and depth. The highest abundance of organisms occurred in April at the end of the dry season. According to HSI and GSI, two reproductive seasons were recorded in June-September and January-March. Morphometric variables statistically different between males and females were cephalothorax width, length and width of chelae, and dactylus. In addition, it was recorded that the average length of P. clarkii in the Taxhimay reservoir is larger than that reported in its natural distribution area and other places where it has been introduced into Mexican territory and Europe. Conclusion: The environmental conditions of the Taxhimay reservoir are conducive to the establishment and growth of P. clarkii, thereby endangering native species in central Mexico.
Crustacea; morphometry; invasive species; sex ratio; red swamp crayfish; seasonality
Comparative osteology of the caudal skeleton and vertebral column of the freshwater fish Tlaloc (Cyprinodontiformes: Profundulidae)
Introduction: The family Profundulidae is a lineage of freshwater fish, with a limited geographical distribution extending from Southern Mexico to Central America, composed of two genera Profundulus and Tlaloc; the latter comprised only four species; however, studies based on the analysis of osteological characters are scarce for this family of fish. Objective: To describe the anatomy of the caudal bones and backbone of all species of the genera Tlaloc. Methods: A comparative analysis was performed on 44 cleared and stained specimens to identify the differences and similarities of backbone elements and the organization of the caudal skeleton among the species. Results: The comparison of the caudal skeleton in the species of the genus Tlaloc, revealed a very similar pattern in the morphology of the species; however, some characteristics were detected that may be useful for discrimination of species of the genus; the triangular shaped hipural plate is a characteristic that has only appeared in T. labialis, while in the rest of the species (T. candalarius, T. portillorum and T. hildebrandi), the hypural plate is fan-shaped. The total number of vertebrae, including the vertebral centrum, in the four species of the genus Tlaloc ranged from 33 to 38, of which 15-17 were abdominal vertebrae and 17-21 caudal vertebrae; T. portillorum had the lowest number of total vertebrae (33); while T. labialis had the highest number of total vertebrae (37-38) Conclusions: The consistent relationship to these skeletal elements suggests that the vertebrae and caudal fin ray count is a character of fundamental nature for the profundulid fishes, giving it particular taxonomic significance in that group.
caudal skeleton; endemic fish; morphology; Profundulidae; vertebrae
Effects of seedlac on soil bacterial diversity: An indication of environmental safety
Introduction: Lac resin, the only natural resin of animal origin, is exclusively produced by the lac insect (Kerria spp.). It is non-toxic and considered biodegradable. However, the bacteria involved in biodegradation have not been explored. Moreover, the fate of the soil bacteria during biodegradation has not been studied so far. Objective: To explore the fate of soil bacteria due to the burial of seedlac in soil to ascertain whether seedlac is environmentally safe, and to explore the possibilities of identifying any bacterial flora involved in lac biodegradation. Methods: The study began in 2016 by burying seedlac samples (semi-refined lac resin product) in the field soil and pot soil under replicated conditions. The seedlac samples were drawn from the soil in 2019, and the soil adhering to the seedlac samples was used in further experiments. The bacterial diversity of these soils was documented by sequencing the V3-V4 region of 16S rRNA through the Illumina NGS platform. Results: No significant variations were obtained in the soil bacterial diversity between samples except for the marginal increase in the count of Actinobacteria, Myxococcales, Gemmatales, Gemmataceae, the WD2101-soil group in seedlac buried pot soil, and Proteobacteria and Acidobacteria in field soil. Most of these bacterial groups are known to degrade complex organic polymers. Conclusions: Since there are no changes in the soil bacterial diversity due to seedlac burial, it may be concluded that seedlac does not affect the soil microflora and is safe for the soil environment.
seedlac; shellac; microbiome; lac insect; soil bacteria; lac resin
Mitochondrial sequencing to guide the management of endangered turtles in Colombia
Introduction: Turtles are extensively harvested to supply the demand for food, pets, and products. Conservation strategies often involve the release of seized individuals and ex-situ breeding programs. However, several traded species have particular genetic characteristics, and the origins of captive individuals are often unknown. Despite their potential to aid in the recovery of populations, these strategies have faced criticism due to the risk of outbreeding depression and genetic diversity loss. Objective: To explore the use of mitochondrial sequencing to estimate the origin of captive individuals from three of Colombia's most traded turtle species: Chelonoidis carbonarius, Trachemys venustacallirostris, and Rhinoclemmys melanosterna. Methods: Firstly, we constructed genetic reference databases using 350 sequences from previous phylogeographic studies and new ones from individuals with known origins. Secondly, through phylogenetic and population genetics analyses we delimited phylogeographic groups. Thirdly, we compared the sequences of 157 turtles of unknown origins, successfully assigning them to their species and the most likely areas of origin. Results: We identified genetic structure in wild populations, heterogeneity of origins in captive individuals, and complex trade networks involving harvesting from multiple distant poaching areas and transportation to central regions. Conclusions: This study shows the efficacy of mitochondrial molecular markers in determining the possible region of origin for confiscated turtle individuals affected by illegal trade and emphasizes the importance of intra-specific conservation efforts to safeguard Colombian wildlife’s genetic identity and diversity.
Sporogenesis and ultrastructure of spores in the fern Anemia hirsuta (Anemiaceae)
Introduction: Research into the ontogeny of sporangia and sporogenesis of leptosporangiate ferns is scarce in the scientific literature. Objectives: To describe and analyze the ontogeny of sporangia, sporogenesis, micromorphology, and ultrastructure of mature spores of the fern Anemia hirsuta. Methods: Fertile fronds of A. hirsuta were processed according to standard protocols for sectioning and embedding samples in paraffin and resin. Sections in paraffin were stained with safranin-alcian blue, Toluidine Blue, and PAS/amidoblack. Sections in resin were stained with Toluidine Blue. The samples were prepared for observation under scanning electron microscopy (SEM) to yield detailed descriptions. Mature spores were analyzed by X-ray energy dispersion (XEDS). Ultrathin sections were obtained for transmission electron microscopy (TEM) observation. Results: The entire leptosporangium is formed from a basal and an apical cell derived from a single epidermal cell of the fertile pinna. The mature leptosporangia are globose, with a subapical ring and a short pedicel. During development, the tapetum is initially cellular, and then becomes plasmodial. The sporocytes undergo simultaneous meiotic division to form tetrads of spores in a tetrahedral arrangement. The exospore is formed first, with two layers, a very thin internal layer and a thick outer layer, followed by the endospore, and finally the perispore. The spores are trilete and muriform, with simple or branched siliceous microspines. The perispore associated with the muri and grooves appears to be highly organized with evident ultrastructural differences. Conclusions: The ontogeny of the sporangia and sporogenesis of A. hirsuta is similar to that previously described for leptosporangiate ferns and recorded in some related fossil species. The highly structured and organized perispore is observed. A high silica content in the microspines of the sporodermis is herein reported for the first time in this group.
Anemiaceae, sporogenesis, sporocytes, sporodermis, tapetum, ultraestructure
High richness and spatio-temporal turnover of insects in urban environments: A case in a Latin American capital
Introduction: Urban ecosystems are spaces in the city that provide ecosystem services and house a wide diversity of species. One of the key components that maintain different types of processes is insects. Objective: To characterize insect communities in four parks in a district of Lima by analyzing their composition and structure in two seasons of the year. Methods: For this evaluation, two samplings (winter and summer) were carried out using four traps (pitfall, canopy malaise, ground-level malaise, and night trap). Results: The results show a) a high richness with 191 registered morphospecies, grouped into 12 orders and 8 functional groups; b) a low similarity between parks (less than 40 % for the Jaccard index), which reveals a high spatial turnover; c) differences in community composition between winter and summer (temporal turnover), with greater richness and abundance of individuals in the warm season (139 morphospecies and 1 214 individuals, versus 105 morphospecies and 731 individuals for summer and winter respectively) and d) the variation of functional groups at both times of the year. Conclusion: The results show a high diversity and invite us to continue the study of insect diversity in urban ecosystems on a broader scale. Information Decision-makers must be considered this to implement measures that allow maintaining this richness of species in a framework where citizens can value and get benefits by the important role of these organisms in the city.
arthropofauna; insect diversity; urban ecology; Miraflores; Peru
Two decades of jaguar and puma (Carnivora: Felidae) activity in lowland forest of eastern Ecuador
Introduction: Jaguars (Panthera onca) and pumas (Puma concolor) are the two largest terrestrial predators in lowland Neotropical forests and as such, are important contributors to the ecosystem. Yet, long-term studies on their temporal and spatial patterns of occurrence are not common. Objectives: To update a previous eight year (2005-2012) camera-trap study on jaguars at Tiputini Biodiversity Station, Yasuní Biosphere Reserve, with data from 2014 through 2023; and to add complementary information on pumas. Methods: We used camera traps set along trails or at mineral licks to document the occurrence of jaguars and pumas. Individual jaguars were identified by their distinctive coat patterns. Results: Capture rates from 2014 to 2023 varied from 0 to 2.94 images/100 trap days for jaguars and from 0.46 to 4.88 for pumas. These rates were similar or increased across all years for both species. We identified 28 individual jaguars during the second sample period, including 18 males and seven females. Periods between captures ranged from 1 to 84 months, with eight individuals recorded over at least 36 months. Including images from the first period (2005-2012), when 21 individuals were identified, it is likely that ~50 individual jaguars have occurred in or close to the research station over 19 years. Jaguars were primarily active during daylight hours, while pumas were more active at night. Conclusions: TBS is embedded within a large biosphere reserve but is too small (~670 ha) to cover the home range of either species. Nonetheless, given the number of records and the fact that capture rates have not declined in the past two decades, this region is important for the conservation of these two species and the many prey they depend on.
camera trap, long-term, Neotropical, temporal, Tiputini Biodiversity Station, Yasuní
The influence of multiscale environmental variables on beta diversity of ichthyofauna in Andean lotic systems
Introduction: Freshwater ecosystems are some of the most threatened globally, including their ichthyofauna. To understand the factors that affect species composition and distribution of fish communities in rivers, it is important to include different assessment scales. Gradients of natural and anthropic origin converge in the Garagoa River, an ideal condition for the study of impact of multi-scale variables on freshwater ichthyofauna. Objective: evaluate the influence of variables at a local and landscape scale on the fish communities of the Garagoa River basin, through the analysis of beta diversity partitioned into the turnover and nesting components. Methods: Sampling was carried out in 36 transects of 100 m, between February and July 2021. The collection was carried out using electrofishing and trawl nets and physical, chemical and morphological characteristics of the section (local variables) were recorded. Using secondary information, information on land use, geomorphological and bioclimatic characteristics (landscape variables) was obtained. Beta diversity was calculated and the influence of local and landscape variables on this component was analyzed, using Principal Component Analysis PCA and Distance-Based Redundancy Analysis dbRDA. Results: We recorded 22 species from 10 families and five orders. The dissimilarity in species composition was high (93 %), 81 % explained by species turnover. These components were related to local variables, land use, geomorphological and bioclimatic characteristics. Conclusions: The species composition in the Garagoa River basin is distributed according to the elevation gradient and is affected by a set of variables at the local and landscape scale that include natural characteristics and conditions generated by human activities. The most relevant are the physicochemical characteristics of the water, the morphology of the channel, the quality of the riverside vegetation, the characteristics of the relief, as well as the distribution of areas with natural cover and areas affected by agricultural, livestock, mining or urban processes.
physicochemical characteristics; land uses; geomorphological variables; landscape limnology; Orinoco River Basin; Meta River; Colombia
Long-term monitoring of ocelots Leopardus pardalis (Carnivora: Felidae) in Tortuguero National Park, Costa Rica
Introduction: The ocelot Leopardus pardalis, though currently listed as Least Concern on the IUCN Red List, has a declining population, and faces threats such as habitat loss and fragmentation and hunting across the entirety of its geographical range, from the Southwestern United States to Northern Argentina. Being a cryptic species and with few studies monitoring ocelots over multiple years, there is a lack of information regarding ocelot ecology. Objective: To further understand the behaviour and population dynamics of ocelots within the study area, Tortuguero National Park (45 755 ha), Costa Rica, by analysing data from a long-term camera trapping study (2011-2022). Methods: Individual ocelots were identified using their unique spot markings. Sex ratio, daily activity patterns, and behaviour were evaluated, whilst ocelot minimum age was estimated for each individual and designated as either resident or transient based on the number of consecutive years observed in the study. Results: A total of 30 individual ocelots were identified (12 females, 18 males). The daily activity pattern (nocturnal) and sex ratio (1 : 0.7) were consistent with that described for the species. The movement of one individual from Tortuguero National Park to Pacuare Nature Reserve, 41 km South, highlights the importance of wildlife corridors for the species. The study also revealed evidence of a female ocelot at least 14 years of age. There are very few published occurrences of an ocelot this old in the wild. Scent marking behaviour was also recorded. Conclusions: This is the longest monitoring effort for ocelots in the country, to our knowledge. Our results highlight the importance of and need for further long-term studies of ocelots to enhance understanding of the species and thus promote the conservation of the species and its habitat.
Ecological Quality Index based on phytoplankton in the lower Magdalena River basin, Northern Colombia
Introduction: The Magdalena River in Colombia has a high anthropic intervention, and this high load of pollutants that enter mainly in the middle and upper basin of its course are becoming increasingly noticeable in the lower basin. Objective: This study evaluated the environmental condition of a section of the Magdalena River in the lower basin as it passes through the Department of Atlántico, using the Ecological Quality Index (EQI) based on phytoplankton. Methods: Six sampling events were carried out between 2021 and 2022, in order to cover contrasting moments of the hydrological regime, at six monitoring stations on the Western bank of the river. Physicochemical and phytoplankton variables were sampled to establish reference categories based on the EQI. Results: Conductivity was determined as the variable that explained the greatest variation in the environmental gradient, generating reference ranges to establish categories of poor, fair and good ecological quality. 77 phytoplankton morphospecies were recorded, of which five were sensitive to the physicochemical conditions of the Magdalena River, with high optimum values and low tolerance limits: Pinnularia sp2, Diatoma sp3, Navicula sp1, Closterium limneticum, C. rostratum. Conclusions: In general, the Magdalena River in the Atlántico showed a fair ecological quality condition, which deteriorated even more during the dry periods of the year. The EQI showed a relationship with the proportion of diatom groups and the abundance of phytoplankton, obtaining better quality values when diatoms predominate over the cyanobacteria group and when the abundance of the phytoplankton is relatively low.
algae; bioindicators; ecosystem condition; freshwater; water quality
Marine macroalgae as habitat: effect of their morphology on the composition of polychaetes (Annelida: Polychaeta) and sipunculans (Annelida: Sipuncula)
Introduction: Marine macroalgae exhibit a wide variety of shapes and sizes, influencing habitat preferences for various organisms, including polychaetes and sipunculans. Objective: To evaluate the relationship between the richness and abundance of polychaetes and sipunculans with red, green, and brown marine macroalgae using specimens collected in Isla Cayo Serrana, Colombian Caribbean, deposited at the Colecciones Biológicas de la Universidad CES (CBUCES). Methods: To estimate the richness and abundance of polychaetes and sipunculans associated with macroalgae, the specimens were separated from each batch of macroalgae. Also, a χ2 test was performed to evaluate if there was an association between annelids and macroalgae. In addition, some morphological measurements were taken for green and red algae, and the relationship between algae morphological complexity and richness and abundance of polychaetes was assessed using Spearman’s correlation coefficient. Results: A total of 460 polychaetes and eight sipunculans were recorded in this study, distributed in 42 species. The polychaete family with the highest richness and abundance was Syllidae, whereas in sipunculans was Phascolosomatidae. Herein, we did not find an association between red, green, and brown macroalgae regarding the richness and abundance of polychaetes and sipunculans. However, a correlation (ρ 0.56–0.78, p < 0.03) was found between some morphological measurements of width, leaf area, wet weight, and displaced volume of green macroalgae of the genus Halimeda with the polychaetes richness and abundance. In contrast, there was no correlation between measurements of red macroalgae (Jania and Amphiroa) and polychaete richness and abundance (ρ between -0.1 and 0.39). Conclusions: This study underscores the relevance of specific morphological attributes of green macroalgae (Halimeda) in enhancing polychaete richness and abundance.
algal fronds; Cayo Serrana Island; ecology; morphological complexity; taxonomy
Radiolarians (Class Polycystina) indeep-sea sediments from the Pacific Ocean off Costa Rica
Introduction. Radiolarians are an important group of marine planktonic protists. The polycystines (Phylum Radiozoa, Class Polycystina) are a group of radiolarians whose skeletons are made of opal (amorphous silica) and form the basis for their taxonomic classification. There are few recent studies of radiolarians in Costa Rica. Objective. This research seeks to create the first taxonomic guide of radiolarians present in Holocene sediments (from 11 000 years ago to the present) of the Costa Rican Pacific seabed. Methods. Between late 2018 and early 2019, two oceanic expeditions: Rock Hits and Costa Rica Deep-Sea Connections, respectively, collected 13 sediment cores from the Costa Rican Pacific seabed. Using a modified methodology created for these investigation, 64 samples were obtained from which radiolarian remains were extracted for taxonomic analysis. Obtained radiolarians were mounted for taxonomic analysis using optical and scanning electron (SEM) microscopy. Results. A total of 119 species of Polycystina were identified, distributed among 15 families belonging to the orders Collodaria (one family and eight species), Spumellaria (seven families and 62 species), and Nassellaria (seven families and 49 species). Conclusion. This study identifies several taxa (119) like those reported in studies conducted near the Pacific coast of Costa Rica, but less than half of those reported from the Eastern Equatorial Pacific (EEP).
Radiolaria; Polycystina; marine zooplankton; taxonomy; descriptive morphology; ocean floor; marine sediment cores
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