Artículos científicos

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A new species and three hybrids in the ferns from Cocos Island, Puntarenas, Costa Rica
(Universidad Nacional (Costa Rica), 2017-12) Rojas Alvarado, Alexander
Una nueva especie y tres híbridos en helechos para la Isla del Coco, Puntarenas, Costa Rica. Una especie nueva y tres híbridos de helechos para la Isla del Coco (Costa Rica) son descritos e ilustrados aquí: Nephrolepis cocosensis A. Rojas, Cyathea × robusta A. Rojas, Elaphoglossum × intermedium A. Rojas y Tectaria × epilithica A. Rojas. La nueva especie difiere de Nephrolepis rivularis (Vahl) Mett. ex Krug por su hábitat terrestre, frondas más pequeñas, pinnas más pequeñas and estas perpendicular al raquis, pinnas marginalmente lobuladas a bilobuladas distalmente, escamas del raquis pardo pálido con el punto de inserción pardo oscuro, escamas de la lámina 0.2–0.4 mm en diámetro, algunas veces reducidas a puntos resinosos, soros submarginales, muchas veces en los lóbulos internos de cada segmento, indusios cordiformes and basalmente adheridos, estos pardo pálidos con el punto de inserción pardo oscuro. El primer híbrido es intermedio entre Cyathea alfonsiana L.D. Gómez y C. notabilis Domin, en tamaño del tronco, tamaño y forma de las escamas del rizoma y base del estípite, tamaño de las frondas, pares de venas por segmento and grado de división de estas and y tamaño de los parafisos, pero tiene frondas más grandes que ambos progenitores, por esta razón el nombre del epíteto. Elaphoglossum x intermedium es un híbrido entre E. alvaradoanumA. Rojas y E. crinitum (L.) Christ, el cual es caracterizado por escamas del estípite y lámina pardos, lámina con base cuneada and ápice obtuso, y venas parcial e irregularmente anastomosadas. Tectaria x epilithica tiene caracteres intermedios entre T. incisa Cav. y T. mexicana (Fée) C.V. Morton, y es fácil de reconocer porque tiene lámina 1-pinnado-pinnatífida y tamaño intermedio entre las escamas del rizoma.
A checklist of the amphibians and reptiles of Río Macho Biological Station, Provincia de Cartago, Costa Rica
(Check List vo.11 no.6 article 1784 1-10 2015, 2015-11-02) Acosta-Chaves, Victor; Chaves, Gerardo; Abarca, Juan G.; García-Rodríguez, Adrián; Bolaños, Federico
We provide a checklist of the amphibians and reptiles of Río Macho Biological Station (RMBS), Costa Rica. During a period of a year (2012–2013) we conducted visual and acoustic surveys in a natural mature forest plot (>50 years old) (MF), secondary forest plot (~17 years old) (SF), in open areas and riparian forest at RMBS. We found a total of 11 species of amphibians and 15 species of reptiles belonging to 11 taxonomic families. We also compared the diversity of the MF against the SF. The MF contained 10 species (five amphibians and five reptiles) and the SF seven (three amphibians and four reptiles), with similar dominance between sites. Unfortunately, some forest and riparian species have vanished at this elevation after an enigmatic decline, according to historical literature pristine areas should contain higher species richness. Perhaps, the secondary forest will provide an available habitat for an important percentage of the remaining forest species.
A dynamic simulation model for the blooming of Oscillatoria agardhii in a monomictic lake
(Elsevier, 1995-01-15) Jiménez, Ricardo; Verreth, Johan; Steenbergen, Kees; Moed, Jan; Machiels, Marcel
The occurrence of phytoplankton blooms is a common problem in water bodies. The quantitative description of the algal population growth is of primary importance to understand the mechanisms which lead to these phytoplankton blooms, hence also for the development of a successful water-quality management. Due to the high degree of complexity of phytoplankton blooms, dynamic simulation models may be a powerful tool to study and elucidate the mechanisms leading to these blooms. In the present study, a simulation model for the blooming of a natural population of Oscillatoria agardhii in Lake Vechten (lat. 52°04′N, long. 5°05′E, the Netherlands) using measured temperature, filament length and nutrient concentrations as external drives, is presented. The lake was sampled weekly from January to the middle of May, 1992. Temperature, nutrient concentration (nitrate and phosphate in the water) and filament length were recorded. Because cell size was constant, filament length could be converted to number of cells per litre to estimate algal biomass. To implement the model additional information, e.g. some algal growth parameters, was obtained from the literature. The model simulated well the growth of the Oscillatoria agardhii population in the lake during the research period. According to the model, temperature was the most important rate-limitating factor for growth at the beginning of the year. Nutrient limitation became increasingly important while the importance of temperature limitation decreased during the season. During the whole period, light was strongly limiting and became the most important rate-limiting factor in the second week of April. Via sensitivity analysis, the model showed to be highly affected by temperature-related factors, and it was useful in the identification of research needs.
A management plan for the sport fishery of Parachromis dovii (Pisces: Cichlidae) in Hule lake, Costa Rica
(Universidad de Costa Rica, 2000-06) Tabash, Farid; Guadamuz, Emilier
A first attempt to regulate the fishing activity while preserving the species and its habitats is presented for Hule lake. We intensively sampled the "guapote" between March 1996 and April 1997 using monofilament gill nets and a floating line, collecting 421 individuals. P. dovii biomass was relatively low; this species had a long life cycle (8-10 years) and the growth oscillation was low (C=0.3). Maximum life expectation was estimated at 12 years and the point of minimum growth coincided with the spawning that takes place between November and December. After spawning, P. dovii take around seven months to reach recruitment size (54.6 mm). The length for sexual maturity was 134 mm Lt, which indicates that this species is viable for reproduction soon after leaving the protection zones around the lagoon. "Guapote" sport fishing in the Hule lake is in equilibrium, the renewal rate is 80%. An increment in the actual fishery effort is not recommended, since it could seriously affect the natural renewal capacity of the stock.
A multidisciplinary approach using hydrogeochemistry, δ15NNO3 isotopes, land use, and statistical tools in evaluating nitrate pollution sources and biochemical processes in Costa Rican volcanic aquifers
(Elsevier B. V., 2024) Madrigal-Solís, Helga; Vadillo Pérez, Iñaki; Jiménez Gavilán, Pablo; Fonseca Sánchez, Alicia; Calderón Sánchez, Hazel; Gómez - Cruz, Alicia; Herrera-Murillo, Jorge; Pérez-Salazar, Roy
Nitrate pollution threatens the Barva and Colima multi-aquifer system, the primary drinking water source in the Greater Metropolitan Area of Costa Rica. In addressing nitrate contamination dynamics, this study proposes an integrated approach by combining multivariate statistical analyses, hydrochemical parameters, sewage discharge, and regional land-use and land-cover patterns to assess the extent and degree of contamination, dominant biogeochemical processes, and refine the interpretation of nitrate sources previously derived solely from δ15NNO3 information. Over seven years (2015-2022), 714 groundwater samples from 43 sites were analyzed for nitrate and major ions, including two sampling campaigns for dissolved organic and inorganic carbon, nitrite, ammonium, FeTotal, MnTotal, and δ15NNO3 analyses. The findings presented elevated nitrate concentrations in urban and agricultural/urban areas, surpassing the Maximum Concentration Levels on several occasions, and oxidizing conditions favoring mineralization and nitrification processes in unconfined Barva and locally confined Upper Colima/Lower Colima aquifers. Similar nitrate contents and spatial patterns in agricultural and urban zones in the shallow Barva aquifer suggest comparable contributions from nitrogen fertilizers and urban wastewaters despite the gradual increase in urban land cover and the reduction of agricultural areas. Isotopic analyses and dissolved organic carbon (DOC) indicate a shift in nitrate sources from agricultural to urban areas in both Barva and Colima aquifers. Principal Component and Hierarchical Cluster Analyses link land use, nitrate sources, and water quality. Three distinct sample clusters aligned with forest/grassland, agricultural/urban, and urban land use, emphasizing the impact of anthropogenic activities on groundwater quality, even in the deeper Colima aquifers. The study challenges nitrate isotope mixing models, enhancing accuracy in identifying pollution sources and assessing the spatial extent of contamination by incorporating DOC and other hydrochemical parameters. Similar outcomes, with and without the use of nitrate isotopes, reinforce the usefulness of the integrated approach, providing a practical and cost-effective alternative.
A new Costa Rican species of Drosophila visiting inflorescences of the hemi-epiphytic climber Monstera lentii (Araceae)
(Universidad Nacional, Costa Rica, 2018-09) Vilela, Carlos; Prieto, Danyi
Drosophila monsterae sp. nov. is described from 11 males and 13 females collected from the inside of closed inflorescences of Monstera lentii (Araceae) at 1810 m altitude in the Forest Reserve of Cerro de La Carpintera, Canton La Unión, Province of Cartago, Costa Rica. Although flies have been seen wandering and copulating inside the floral chambers of closed inflorescences during the floral female phase, eggs or larvae have not yet been found either in the spathe or in the fleshy spadix. The new species is related to Drosophila tristani Sturtevant, 1921, from San José Costa Rica, from which it differs mainly by having smaller slightly circular compound eyes, distinctly broader genae (cheek index ca. 2.4 vs 5 in D. tristani), and the inner capsule of spermathecae with an unusual folded duct at basal half of its very wide introvert. This is the eighth species to be included in the New World, essentially Neotropical, subgenus Phloridosa. Photomicrographs of male and female terminalia are also provided. © 2018 Sociedade Brasileira de Entomologia
A new giant species of placented worm and the mechanism by which onychophorans weave their nets (Onychophora: Peripatidae)
(Universidad de Costa Rica, 2010) Morera, Bernal; Monge-Nájera, Julián
Onychophorans, or velvet worms, are poorly known and rare animals. Here we report the discovery of a new species that is also the largest onychophoran found so far, a 22cm long female from the Caribbean coastal forest of Costa Rica. Specimens were examined with Scanning Electron Microscopy; Peripatus solorzanoi sp. nov., is diagnosed as follows: primary papillae convex and conical with rounded bases, with more than 18 scale ranks. Apical section large, spherical, with a basal diameter of at least 20 ranks. Apical piece with 6-7 scale ranks. Outer blade 1 principal tooth, 1 accessory tooth, 1 vestigial accessory tooth (formula: 1/1/1); inner blade 1 principal tooth, 1 accessory tooth, 1 rudimentary accessory tooth, 9 to 10 denticles (formula: 1/1/1/9-10). Accessory tooth blunt in both blades. Four pads in the fourth and fifth oncopods; 4th. pad arched. The previously unknown mechanism by which onychophorans weave their adhesive is simple: muscular action produces a swinging movement of the adhesive-spelling organs; as a result, the streams cross in mid air, weaving the net. Like all onychophorans, P. solorzanoi is a rare species: active protection of the habitat of the largest onychophoran ever described, is considered urgent.
A new giant velvet worm from Costa Rica suggests absence of the genus Peripatus (Onychophora: Peripatidae) in Central Americ
(Universidad de Costa Rica, 2020-02-03) Barquero González, José Pablo; Sánchez-Vargas, Steven; Morera, Bernal
Introduction: Neotropical onychophoran taxonomy and diversity has been poorly investigated. Recent studies have discovered problems in species classification: they have questioned the accepted genera and the actual number of species. This is true in Costa Rica, where several unidentified species have been reported. Objective: The objective of this investigation was to evaluate the occurrence of the accepted genera in this country, and to describe a new genus and species from Central America. Methods: In 2017, we collected one onychophoran in the Keköldi Indigenous Reserve in Talamanca, Limón, Costa Rica. The specimen gave birth to several offspring. Therefore, seven organisms were analyzed. Light microscopy was used to observe the gross morphology in all samples. The detailed morphology was studied in the biggest specimen with scanning electron microscopy; after that, we performed a phylogenetic analysis with the corresponding sequence of COI. Results: According to our results, a new genus and species of giant onychophoran was found. The genus was identified by its giant size, apical piece of seven scale ranks, large conical primary papillae, dorso-median furrow flanked by two-three accessory papillae, the absence of hyaline organs and a marked sexual dimorphism with respect to the number of legs. The new species presents a particular head pattern, as well as novel structures like cephalic papillae, accessory papillae with rudimentary apical pieces, and a lack of antennal chemoreceptors. Phylogenetic analysis rendered our genus as monophyletic and includes Peripatus solorzanoi, which is grouped within the Central American clade.As our species is clustered inside the Costa Rica-Panamanian group, it is not related to the Caribbean Island nor Guyanan Shield samples, home of Epiperipatus and Peripatus respectively. Therefore, we suggest that those genera do not occur in Central America, and a new genus exists: Mongeperipatus, gen. nov.Conclusion: We concluded that Costa Rica is home to a diversity of undescribed onychophorans that requires specific studies to help clarify the taxonomy and evolutionary relationships of the group to justify their protection.
A new species of Elaphoglossum Schott ex J. Sm. (Dryopteridaceae) from Costa Rica
(Universidad Nacional (Costa Rica), 2017-12) Rojas Alvarado, Alexander; Muñoz-Cambronero, Pablo Elías
Una especie nueva de Elaphoglossum Schott ex J.Sm. Dryopteridaceae) para Costa Rica.Una especie nueva de ElaphoglossumSchott ex J. Smde la sección UndulataChrist es descrita aquí: Elaphoglossum pallidosquamum A. Rojas & P. Muñoz. La nueva especie es similar a E. herpestes por su rizoma largo ascendente, pero difiere por escamas del rizoma no cordadas basalmente (vs. cordadas) y más pálidas pardo-amarillentas con margen blanquecino o completamente blanquecinas (vs. castañas), escamas del estípite adpresas (vs. adpresas a moderadamente patentes) y más densas, lámina más angosta 2.5-4 cm de ancho (vs. 5-6.5 cm) con base anchamente cuneada a obtusa (vs. redonda), lámina con diferentes tipos de escamas las costales imbricadas (vs. distantes entre sí), escamas adaxiales densas (vs. dispersas), escamas abaxiales enrrolladas y moderadamente densas (vs. escamas abaxiales planas y dispersas) y, escamas marginales muy densas (vs. moderadamente densas a dispersas) y estas más pálidas blanquecinas a amarillo pálido (vs. pardas).
A new species of Seticeros from Costa Rica (Coleoptera, Cerambycidae, Prioninae)
(Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 2011) Ramírez Campos, R.; Esteban Duran, J.R.; Santos Silva, A.
A new species of Seticeros Perger & Santos-Silva, 2010 (Prioninae: Callipogonini) from San Isidro del General, San José, Costa Rica is described and illustrated. A key to the species of Seticeros is added.
A new vanilla species from Costa Rica closely related to V. planifolia (Orchidaceae)
(European Journal of Taxonomy, 2017-02-22) Azofeifa Bolaños, José B.; Gigant, L. Rodolphe; Nicolás García, Mayra; Pignal, Marc; Tavares González, Fabiola B.; Hagsater, Eric; Salazar, Gerardo; Reyes Lopez, Delfino; Archila Morales, Fredy Leonel; García-García, José A.; Da Silva, Denis; Allibert, Agathe; Solano Campos, Frank; Rodríguez Jimenes, Guadalupe del Carmen; Paniagua Vásquez, Amelia; Besse, Pascale; Pérez Silva, Araceli; Grisoni, Michel
We describe a new vanilla species growing in sympatry with Vanilla planifolia Jacks. ex Andrews (Orchidaceae) in the province of Limón, Caribbean coast of Costa Rica. The morphology of the reproductive and vegetative organs observed on vines cultivated under shade-house, the nuclear (Internal Transcribed Spacer) and plastid (matK) nucleotide sequences, as well as the contents of aromatic compounds measured in ripe fruits, show that this species is close to but distinct from V. planifolia. The name V. sotoarenasii M.Pignal, Azofeifa-Bolaños & Grisoni sp. nov. is proposed for this new Vanilla species endemic in Costa Rica. It is especially distinguished from V. planifolia by a reduction of about 30% of the size of the fruits and flowers, by a divergence of ITS sequences for at least two species-conserved nucleotides compared to seven other species of the V. planifolia group, and by the presence of anisic compounds and low content of phenolic compounds (including vanillin) in the fruits. These results confirmed the extension of the area of distribution of V. planifolia southward to Costa Rica, where a recent speciation process occurred. Because of its particular agronomic and aromatic properties, V. sotoarenasii sp. nov. could represent a valuable biological resource for the vanilla industry.
A novel host-adapted strain of SalmonellaTyphimurium causes renal disease in olive ridley turtles (Lepidochelys olivacea) in the Pacifc
(Springer Nature, 2019-06) Work, Thierry; Dagenais, Julie; Stacy, Brian; Ladner, Jason T; Lorch, Jeffrey M; Balazs, George H; Barquero Calvo, Elías; Berlowski-Zier, Brenda; Breeden, Renee; Corrales Gómez, Natalia; González Barrientos, Rocío; Harris, Heather S.; Hernández Mora, Gabriela; Herrera-Ulloa, Angel; Hesami, Shoreh; Todd Jones, T.; Norton, Terry M.; Rameyer, Robert A.; Taylor, Daniel R.; Waltzek, Thomas B.
Salmonella spp. are frequently shed by wildlife including turtles, but S. enterica subsp. enterica serovar Typhimurium or lesions associated with Salmonella are rare in turtles. Between 1996 and 2016, we necropsied 127 apparently healthy pelagic olive ridley turtles (Lepidochelys olivacea) that died from drowning bycatch in fisheries and 44 live or freshly dead stranded turtles from the west coast of North and Central America and Hawaii. Seven percent (9/127) of pelagic and 47% (21/44) of stranded turtles had renal granulomas associated with S. Typhimurium. Stranded animals were 12 times more likely than pelagic animals to have Salmonella-induced nephritis suggesting that Salmonella may have been a contributing cause of stranding. S. Typhimurium was the only Salmonella serovar detected in L. olivacea, and phylogenetic analysis from whole genome sequencing showed that the isolates from L. olivacea formed a single clade distinct from other S. Typhimurium. Molecular clock analysis revealed that this novel clade may have originated as recently as a few decades ago. The phylogenetic lineage leading to this group is enriched for non-synonymous changes within the genomic area of Salmonella pathogenicity island 1 suggesting that these genes are important for host adaptation.
A preliminary market research about tambaqui (Colossoma macropomum) in Costa Rica
(Universidad Nacional (Costa Rica), 1996) van Anrooy, Raymon; Günther, Jorge; Boza Abarca, Jorge ; Gálvez, Nazira
En los meses de enero a julio de 1995 se desarrolló una prueba de mercado con el pez de agua dulce “Tambaqui” (Colossoma macropomum) en Costa Rica. Unos 1200 peces de aproximadamente 800g peso promedio se obtuvieron de la estación piscícola de la Universidad Nacional, en La Rita, Guápiles. Un promedio de 20 peces fueron suministrados semanalmente a cada una de 4 pescaderías en Limón, Guápiles, San José y Heredia. El precio al productor fue equivalente de 1,40 dólares/kg, calculado para cubrir los costos de producción, el precio al consumidor fue de 1,97 dólares/kg. Las motivaciones de los consumidores para comprar el pescado fueron: curiosidad, bajo precio, buen sabor y la recomendación de los vendedores. La mayoría de los consumidores apreció mucho el sabor, textura, la frescura, el color y la apariencia de la carne. Algunos criticaron la presencia de espinas intramusculares. El 89% de los consumidores manifestaron que volverían a comprar el pez y el 38% lo preferirían a cualquier otra especie. No hubo ninguna relación (P ≥ 0,05) entre sexo, tamaño de la unidad familiar y nivel de ingresos de los consumidores con las respuestas. La población china fue el único subgrupo identificable entre los consumidores. Casi todos los consumidores opinaron que este pez tiene buenas posibilidades de mercado en Costa Rica. La prueba mostró que el precio puede incrementarse algo más sin perder muchos consumidores, pero hay que promocionar el producto para que sea más conocido entre la población costarricense. Este producto podría cubrir parte de la demanda de pescado entero a bajo precio en Costa Rica.
A proposed solution to the species problem in velvet worm conservation (Onychophora)
(Universidad Estatal a Distancia, 2018) Sosa-Bartuano, Ángel; Monge Nájera, Julián; Morera, Bernal
Onychophorans or velvet worm are the only phylum without extant marine species and the only invertebrates with a true placenta, but most species are rare and thus more likely to become extinct. A key obstacle for their conservation is the time and work needed to describe species with the high standards of current tax onomy, and many species will remain undescribed and without any name for years. Here we propose a way to associate information with undescribed species: “common names”, a solution that has proved its value in ornithology. Onychophoran common names must include a geographic indicator and a description a salient characteristic, and to show its viability, here we apply our proposal to the velvet worm fauna of southeastern Central America. Common names like “Lajas Ferruginous Brown Onychophoran”, “Churuquita Collared Cinnamon Rufous Onychophoran” and “Antón Collared Mauve Onychophoran” will help conservation until formal Latin binomials become available.
A simple method for short-term storage and transportation of spermatophores of Pacific white shrimp (Litopenaeus vannamei)
(Hidrobiológica vol.26 no.1 9-14 2016, 2016) Morales Ureno, Karina; Paniagua Chávez, Carmen; Martínez- Ortega, Alfonso; Castillo - Juárez, Héctor; Alfaro-Montoya, Jorge
The development of a shipping method for spermatophores of the white shrimp Litopenaeus vannamei would open new opportunities for sharing and improving genetic resources of shrimp worldwide. Seventy spermatophores were collected daily for 5 days (a total of 350 spermatophores from 175 shrimp), packed in microcentrifuge tubes containing 100 μL of an extender solution, and placed in a Styrofoam box supplied with a thermal insulating layer and refrigerant pack to keep the samples cooled at ∼14°C. Shipment of samples took ∼26 hours. At arrival, spermatophores were randomly sampled either as soon as the box arrived (∼27 h, Group A) or five hours later (∼32 h, Group B) to assess sperm viability. Spermatozoal morphology was evaluated by microscopy (100 cells per shrimp). Cells without spikes or irregular in shape were recorded as abnormal; otherwise cell morphology was recorded as normal. Spermatozoal viability was assessed by flow cytometry, whereby three populations were identified: (1) cells with intact cytoplasmatic membrane (viable), (2) cells with disrupted membrane (nonviable), and (3) cells in transition, changing from intact to disrupted membrane (transitional). Significant differences were found in spermatozoal morphology between group A and B (p = 0.002), with the highest percentage of normal spermatozoa (92 + 15%) found in Group A. No significant differences were found in viable (p = 0.723) and transitional spermatophore populations (p = 0.595) assessed by flow cytometry. Non-viable populations increased with time in storage (p = 0.039). The highest percentage of non-viable cells (81 + 7%) was obtained in Group B. These results indicate that spermatophores can be cooled and transported to distant locations maintaining normal morphology and viability. These indirect quality indicators suggest that spermatozoa may be used for different purposes, including artificial insemination.
Abundance and size frequency of postlarvae of Penaeus occidentalis in the Gulf of Nicoya, Costa Rica
(Universidad de Costa Rica, 1997) Hiroshi, Kitani
Postlarvae of the Genus Penaeus were collected once a month from November/94 to April/95 at Cocoroca beach in the Gulf of Nicoya, Costa Rica. They were identified morphologically, and those of P. occidentalis were studied. It was revealed that the postlarvae of P. occidentalis occupied 65.6 % of the total individuals collected, and 24.1 - 94.9% of the monthly composition, and their distribution density varied from 0.7-5.8 individuals/m2. The carapace length(CL) of the postlarvae of P. occidentalis ranged from 1.55 to 9.58 mm, which suggested a migratory size of them. The frequency of the CL showed a skewed distribution, which suggested a migratory pattern of the postlarvae of that species. The relative growths of the 6th abdominal somite and the carpus of the third pereopod of the postlarvae of P. occidentalis were also examined against the CL.
Abundancia, biomasa y estructura de la ictiofauna demersal del mar Caribe de América Central
(Universidad Nacional de Costa Rica, 2019-01-31) BENAVIDES, ROSARIO; Campos-Calderón, Fernando
Se analizaron 96 puntos de muestreo realizados a bordo del B/O Miguel Oliver, desde el 3 de enero hasta el 3 de febrero del 2011. En cada punto se llevaron a cabo faenas de pesca de arrastre utilizando una red Lofoten. Los arrastres de 30 minutos de duración cada uno se efectuaron en 25 transectos equidistantes y divididos en estratos según la profundidad local, hasta un máximo de 1500 m. Se encontraron y analizaron un total de 142 especies de peces óseos y cartilaginosos (n = 28 074) pertenecientes a 73 familias diferentes. Se determinó la abundancia relativa, la biomasa y la frecuencia de las capturas. Antigonia combatiamostró la mayor abundancia (58,5 %), Centrophorus granulosus reportó la biomasa más representativa en el estudio (10,9 %) y Nezumia aequalis fue la especie más frecuente (32,6 %). Además, se estudió el ordenamiento espacial en posibles ensamblajes de los peces como respuesta a la profundidad. El análisis de conglomerados (Mantel test r = 0,86; p < 0,05), el de ordenamiento espacial no paramétrico (NMDS) y el de similitud (ANOSIM) suponen suficiente evidencia de que las especies se encontraron agregadas en patrones espaciales con respecto al gradiente de profundidad.
Abundancia, diversidad y categoría ecológica de los peces en estero damas y estero Palo Seco, Costa Rica
(Universidad Nacional (Costa Rica), 2002) Araya, Hubert; Cabrera Peña, Jorge; Protti Quesada, Maurizio; Baldizón Fernandez, Isaac A.
Se trabajó de junio de 1986 a febrero de 1987 en una estación de muestreo en el estero Palo Seco y en dos en el estero Damas (Damas y San Bosco), Pacífico Central, Costa Rica. La temperatura del agua no presentó diferencias significativas entre las estaciones Damas y San Bosco, pero sí entre Damas-Palo Seco y San Bosco-Palo Seco. La salinidad varió significativamente entre las tres estaciones y el pH no mostró diferencias significativas. Se recolectaron representantes de 25 familias, 39 géneros y 54 especies. De las especies, 18 comparten los tres sitios de muestreo, siete se hallaron únicamente en Palo Seco, cinco en Damas y seis en San Bosco. De las especies recolectadas, el 7,41% es compartido entre Palo Seco y Damas; el 3,70% entre Palo Seco y San Bosco y el 22,22% entre Damas y San Bosco. El análisis de similitud determinó que las estaciones Damas y San Bosco comparten un 41,40% de las especies; mientras que Palo Seco solamente presento un 9,9% de especies comunes con el grupo Damas-San Bosco. La mayoría de las especies encontradas fueron de origen marino que utilizan estos dos esteros como área de crianza (42,59%) y alimentación (40,74%); mientras que las de agua dulce, estuarinas y visitantes ocasionales están poco representadas. La mayor diversidad se encontró en San Bosco y se detectaron diferencias estadísticamente significativas en los valores de H' entre las estaciones. La mayor similitud de especies se presentó entre las estaciones Damas y San Bosco, lo que sugiere que estas áreas están bajo una mayor influencia de aguas continentales; lo que propicia que los peces estén más ampliamente distribuidos. Se deduce que la ictiofauna de los esteros estudiados es transitoria en los sitios de muestreo y que la misma se distribuye heterogéneamente.
Actividad hemolítica de la Anémona Marina Aiptasia pallida (Cnidaria: Actiniaria: Actiniidae) de Costa Rica
(Tecnológico de Costa Rica (TEC) (Costa Rica), 2017) Córdoba-Chaves, Adriana; Borbón-Alpízar, Henry; Alvarado Mesén, Javier; Zamora-Rodríguez, Mónica; Soto-Fallas, Roy; Abrego-Ramírez, Daniela
El filo Cnidaria incluye organismos considerados dentro de los más venenosos en la naturaleza. Más específicamente, alrededor de 32 especies de anémonas marinas han sido reportadas como productoras de péptidos y proteínas citolíticas. Este estudio fue llevado a cabo para evaluar la actividad hemolítica del extracto crudo de la anémona marina Aiptasia pallida en Costa Rica. El material biológico fue colectado, triturado, homogenizado y posteriormente centrifugado para la obtención del extracto crudo. El mismo fue caracterizado a través de una evaluación de su actividad hemolítica (HA) con glóbulos rojos de sangre humana (RBC). Interesantemente, los resultados de HA no mostraron rompimiento de los eritrocitos, sin embargo hubo un incremento de la absorbancia en función del tiempo. El extracto crudo reveló la existencia de una banda de proteína alrededor de 30 kDa por SDS-PAGE, no se encontró banda características de actinoporinas en A. pallida. Estos resultados podrían estar asociados con una concentración sub-lítica de otra familia de proteínas las cuales alteran el equilibrio osmótico y cambian el volumen de las células, sin un efecto letal a las concentraciones ensayadas.
Activities That May Influence the Risk of Crocodile (Crocodylus Acutus: Reptilia: Crocodilidae) Attack to Humans in the Tempisque River Area, Guanacaste, Costa Rica
(Universidad Nacional (Costa Rica), 2017-01) Sandoval Hernández, Iván; Duran Apuy, Alejandro; Quirós Valerio, Jacqueline
Una de las mayores poblaciones de cocodrilos de Costa Rica se encuentra en el río Tempisque. La especie está amenazada por la pérdida de hábitat y la cacería, sin embargo, sus poblaciones han crecido debido a la protección otorgada por ley. El estudio se realizó en Guanacaste, Costa Rica. Se hizo una caracterización del conocimiento popular, actividades realizadas y percepciones de 374 residentes de la zona de estudio. Se encontró que el 55% piensa que el cocodrilo es abundante, 70% cree que las poblaciones han aumentado. Las actividades más peligrosas efectuadas son principalmente la recreación, natación y pesca artesanal. Entre ellas se encontraron diferencias significativas entre las proporciones de respuesta (X2: 71, n: 10, p <0.0001). Estas actividades se realizan diariamente (25%), semanalmente (30%), mensualmente (18%), anualmente (10%). No se reconocen los riesgos de ataque ni la densidad de cocodrilos en el río. Así mismo, se muestra una falta de conocimiento acerca la historia natural y ecología de la especie. Las razones de ataque son: la agresividad de los animales y su densidad, encontrándose diferencia entre las respuestas sobre las razones del ataque (X2: 35, n:8 p <0.0001). En general, la percepción de cocodrilo es desfavorable.

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