Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Diel and annual cycle of tropospheric and oceanic variables in Cocos Island, Costa Rica. Meteorological records from gauge stations at Isla del Coco (Cocos Island), Costa Rica, were analyzed. These data are from an automatic weather station and from two pluviograph stations, covering the period 1997-2005. Time series from other historical records and from the nearest island grid point from different public geophysical data sets were also used. The focus was on rainfall, wind, radiation, relative humidity, and air and sea temperature series. Daily and annual cycles were calculated for all the records with hourly resolution and their intraseasonal features were studied, such as maxima values, minima values and transitional periods. Comparisons were done between the stations records and the grid (with broader spatial resolution data). In general, seasonal variations at Isla del Coco were observed to be mainly associated with the meridian migration of the Inter Tropical Convergence Zone; the island is under its direct influence from boreal spring to autumn. Rev. Biol. Trop. 56 (Suppl. 2): 19-29. Epub 2008 August 29.

This study presents a description of the tropical intertidal shores of Cocos Island (Isla del Coco), Pacific, Costa Rica. The intertidal zones were surveyed photographically with 116 digital images of quadrats (25 x 25 cm), and 130 of the cliffs in five days. The percent of cover and abundance of species in the intertidal zones were estimated by digital image analysis. Twenty-three taxa were found, Mollusca was the most specious (12 species). Littorinid and neritid mollusks were dominant in the higher littoral area. The predator snails Plicopurpura patula pansa, and Thais brevidentata, high densities of the pulmonate limpet Siphonaria gigas and some patches with low cover of the barnacle Tetraclita stalactifera were present in the mid-littoral zone. The encrusting algae dominate the rock surface at mid and low littoral and erect-frondose forms were only found in sheltered boulder shores. A high similarity in species identity was found between mainland and insular territories of the eastern tropical Pacific. Panamanian islands were most similar in terms of the algae assemblage of Cocos Island. The Galápagos Islands differ from Cocos Island in their higher erect-frondose and crustose algal cover, and lower densities of S. gigas. Grazing may be an important factor in structuring the intertidal community of Cocos Island and other regions of the eastern tropical Pacific. The main grazer in the cliffs and boulders was S. gigas which was larger in size (5.77 cm ± 1.00) than those of mainland and island sites in Costa Rica and Panama. Boulders and cliffs presented changes in the zonation and densities between sheltered or wave exposed areas. The position of organisms on the intertidal cliffs increased at high tidal level in more exposed sections of the coast. Moreover, topographic characteristics of boulders and cliffs influenced the densities of some gastropods around the island. Shores with ignimbrites, aa lavas or basaltic walls with a slight inclination towards the sea presented high densities of gastropods. The difference in the assemblages at Cocos Island from those of the continental and insular shores indicates high dynamics within intertidal tropical ecosystems. Rev. Biol. Trop. 56 (Suppl. 2): 171-187. Epub 2008 August 29.

Qualitative characterization of the zooplankton of the Cocos Island Marine Conservation Area (Área de Conservación Marina Isla del Coco, ACMIC), Pacific Ocean of Costa Rica. During November 2001, zooplankton samples were obtained from sites around Isla del Coco, a protected oceanic island off the Pacific coast of Costa Rica. Vertical (0-50 m) and horizontal hauls were performed. This first qualitative analysis of the zooplankton shows a very diverse community, with copepods being dominant (68 species). Up to 19 species of Copepoda represent new records for Costa Rican Pacific waters and thus, increase the relative number of species recorded from Costa Rica in relation to the overall copepod species richness of the eastern tropical Pacific. Hyperiid amphipods were represented by 20 species; this is the first reference about this group from waters around Isla del Coco. Other planktic crustaceans recorded were Evadne sp. (Cladocera), Cypridina americana and Euconchoecia sp. (Ostracoda), and unidentified euphausiids and mysidaceans. Six families of planktic gastropods were found, including Limacinidae, Cavolinidae, Pneumodermopsidae, and Desmopteridae; heteropod molluscs were also collected (Pterotracheidae, Carinariidae and Atlantidae), and also the nudibranch Phylliroë bucephala (Phylliroidae). Seven species of chaetognaths were recorded, Flaccisagitta enflata and Serratosagitta pacifica being the commonest. Appendicularians (five species of Oikopleura and Stegosoma) and salps (Salpa sp. and Doliolum sp.) were also present in the samples. Pyrosomatida (Thaliacea) are first records for Costa Rican Pacific waters. The gelatinous zooplankton included seven species of siphonophores and three of medusae, Rhopalonema velatum being the most frequent medusa. Overall zooplankton species diversity (including ichthyoplankton) of Isla del Coco is lower, but not by much, than in the Costa Rica Dome (136 vs 178). Some ideas are discussed about the value of Isla del Coco as a zooplankton diversity hot spot. Rev. Biol. Trop. 56 (Suppl. 2): 159-169. Epub 2008 August 29.

Spatial-temporal tendencies of marine faunal observations in touristic dives (Isla del Coco, Costa Rica). Data on several marine species collected over 15 years (1991 to 2007), by dive-masters of the diving company Undersea Hunter, at 27 sites around Isla del Coco (Cocos Island), Pacific Costa Rica, were analyzed. The goal was to create a base line of the pelagic species that live in the waters of the Island based on reports of their activity during tourist dives. A data matrix was generated and multivariate methods used to determine the patterns of temporal and spacial variation. Variability in the occurrence of several species was high between sites. All sites presented a change in the asemblages during the 1991-92 and 1997-98 El Niño events. However, some sites had more influence by this climatic oscillation. El Niño event had stronger repercussion on the abundance and occurrence of particular species. Elasmobranchs such as the scalloped hammerhead sharks (Sphyrna lewini) and the marbled ray (Taeniura meyeni) showed a negative association with anomalous sea surface temperatures. Starting in 2000 there is a decrease in the average abundances and in the presence of the pelagic species, especially for economically important sharks. These variables reach similar values compared to those of El Niño years. A possible explanation is the increase of illegal fishing that took place around the Island or immediate waters. Some of these are species with great mobility. Nevertheless, some species had a small recovery in recent years. A collaborative program between the Government of Costa Rica and MarViva (a non governmental organization) in recent years has resulted in an improvement in the conservation of the marine fauna of Isla del Coco. Rev. Biol. Trop. 56 (Suppl. 2): 113-132. Epub 2008 August 29.

Distribution and abundance of shallow water echinoderms from Cocos Island, Costa Rica, Eastern Pacific. The distribution patterns of the shallow water echinoderms (down to 18 m deep) around Isla del Coco, Costa Rica, are described. Eighteen sites were evaluated at two depths (6 and 15 m) using transects, and vertical profiles were done between 0 and 18 m deep at four sites. A total of 28 species were observed. The most specious class was Echinoidea with nine species, followed by Asteroidea with seven, and Ophiuroidea and Holothuroidea with six species each. The sea urchin Diadema mexicanum was the only echinoderm present at all sites and depths studied. The highest densities were observed at Dos Amigos at 6 m (6.53 indv/m2), Punta Ulloa (4.37 indv/m2), Roca Sumergida (3.48 indv/m2) and Isla Pájara (2.27 indv/m2). Diadema has shown in the past to be an important element in the balance and recovery of the coral environments. This study reports for the first time the presence in the area of the asteroid Asteropsis carinifera and the sea cucumber Holothuria (Mertensiothuria) fuscocinerea. Rev. Biol. Trop. 56 (Suppl. 2): 99-111. Epub 2008 August 29.

A summary of the available information on stomatopod and decapod diversity of Isla del Coco and records of recently collected species during the CIMAR-MarViva expedition (January 2007) as well as the presence of yet unpublished specimens deposited in the Museo de Zoología, Universidad de Costa Rica, is reported. The material of the CIMAR-MarViva expedition comprised 23 species, including nine species new for the island. Revision of the collection of the Museo de Zoología, including two unpublished records, revealed the presence of additional 12 decapod species not previously reported for the island. Overall, a total of 135 species (6 stomatopods and 129 decapods) has been reported so far for the island, which harbors 29.5% of all decapod species known to occur along the Pacific mainland of Costa Rica, and 16.3% of all decapods reported for the Panamic Province. The most diverse families (including > 10 spp.) at Isla del Coco are Xanthidae (14 spp.), Majidae and Alpheidae (each 11 spp.), and Porcellanidae (10 spp.). There is a strong affinity of the stomatopod and decapod fauna of both Isla del Coco and Islas Galápagos. Rev. Biol. Trop. 56 (Suppl. 2): 79-97. Epub 2008 August 29.

Seabirds of Cocos Island, Costa Rica, and their conservation. The marine avifauna of Cocos Island includes 32 species, 17 genera and nine families. Eight of these species are reproductive residents and 25 are visitors. Among visitors, eight are Nearctic migrants, 11 are tropical species and 13 correspond to the Eastern Pacific geographic range. According to presence/abundance observations, six species are abundant (18.75%), one, common (3.13%), three, uncommon (9.37%), ten, casual (31.25%) and twelve, accidental (37.50%). I recommend a study of human impact, the establishment of an official checklist and periodical monitoring of this avifauna, and a better spatial definition of the coastal marine belt. Rev. Biol. Trop. 56 (Suppl. 2): 133-149. Epub 2008 August 29.

The presence of otarids (Carnivora: Otariidae) at Isla del Coco, Costa Rica. This paper presents a historic revision of the presence of the otarids, Zalophus wollebaeki and Arctocephalus galapagoensis, at Isla del Coco (Cocos Island). Their presence in the Island is accidental and recurrent, maybe in relation with climatic episodes. Isla del Coco does not have the ecological conditions that are necessary for the development of a reproductive colony of these marine mammals. Rev. Biol. Trop. 56 (Suppl. 2): 151-158. Epub 2008 August 29.

The fossil crinoids and associated fauna from the Carboniferous (Mississippian–Pennsylvanian) of Mexico (Sonora, Tamaulipas, Hidalgo, Puebla, Guerrero, Oaxaca and Chiapas States) are described. Data are based on a combination of field and published sources, including seven previously studied localities from the central and southern areas, and four new localities from the northwestern part of the country. A total of 28 morphospecies are reported, seven from the Mississippian and 21 from the Pennsylvanian. Eleven are recorded for the first time in Mexico. These crinoid columnal morphospecies have been reported from the United States of America (Iowa, Illinois, Kentucky, Kansas, Oklahoma, Colorado and Texas), and there are doubtful reports from Poland, and several Eurasian provinces (Western Siberia, Southern Kazakhstan, Pribalkhash and the Czech Republic). Taxa distribution falls within the northwestern Mid-Continent Realm Tropical Climate Zone. The faunal assemblage comprises fusulinids, corals, bryozoans, brachiopods, trilobites, ammonites and conodonts. Fusulinids (e.g. Fusullinella, Triticites, and Parafusulina) have a Tethyan distribution, are also typical of the American Mid-Continental region, and are similar to fauna of the Eurasian-Arctic Province. Corals (Lophophyllidium, Neozaphrentis, Caninia, Caninophyllum, and Lithostrotionella) are present in the Cordilleran province of North America, and in various Eurasiatic provinces. Whereas fenestellid bryozoans (Fenestella) and brachiopods (Neospirifer, Avonia, Wellerella, Composita, and Hustedia) have a cosmopolitan distribution, the ammonite Peritrochia is distributed in the USA, Sicily, Crimea-Urals- central Asia-Timor. Trilobites (Griffithides) and conodonts (Idiognathoides and Neognathodus) are common in Europe, Australia, and Asia. Rev. Biol. Trop. 56 (Suppl. 3): 1-12. Epub 2009 January 05.

Phyllodial pores and the identification of two subspecies of sea urchins in Mexico: Meoma ventricosa grandis (Pacific) and Meoma ventricosa ventricosa (Atlantic). The genus Meoma inhabits Mexican waters and is represented by the subspecies Meoma ventricosa grandis in the Pacific and Meoma ventricosa ventricosa in the Atlantic. Both subespecies are morphologically similar. We studied the morphological differences between Meoma ventricosa grandis and Meoma ventricosa ventricosa, specifically in the patterns of phyllodial pore pairs and kind of sediments where they live. The number of pores differs among subspecies until M. ventricosa grandis reaches 110 mm of total lenght. The difference in the number of phyllodial pores can be an adaptation to the size of silt grain. Rev. Biol. Trop. 56 (Suppl. 3): 13-17. Epub 2009 January 05.