Revista de Biología Tropical

Frequency and pathogenicity of fusarium wilts (Fusarium solani **and Fusarium equiseti) of cotton (Gossypium hirsutum) in Adamawa in Nigeria**

Cotton fungi were surveyed in Ngurore, Adamawa, Nigeria in 1992 and 1993 by counting the number of isolates in each 100 infested plants per plot. Approximately 90% of the isolated fungi were Fusarium solani and Fusarium equiseti, both pathogenic; F. solani isolates were more virulent and frequent than F. equiseti. The high frequency and virulence of both fungi make them important pathogens of cotton in the area.

**Morfología y taxonomía de algunas especies de diatomeas del género Coscinodiscus de las costas del Pacífico mexicano**

- Net phytoplankton samples (30 µm and 54 4µm mesh), from coasts of the Pacific Ocean of Mexico, including coasts of Baja California, the Gulf of California and Tehuantepec (1982-1986), were analyzed to provide a revision of species of the diatom genus Coscinodiscus. Six species were found and studied by light and electron microscopy. Typical references, morphological details, and a brief discussion on morphological variability and taxonomic aspects are given for each species, as well as the local and general distribution. Coscinodiscus radiatus appeared as the most widespread species, perhaps because some taxa have become minor synonyms of it. The valuable taxonomic characters of the genus Coscinodiscus are: form of the valve, presence of valve process, relative height of mantle, other specific characters.

En este trabajo se analizaron muestras de red de fitoplancton procedentes del Pacífico Mexicano, incluyendo los Golfos de California y Tehuantepec, para hacer una revisión actualizada de las especies de diatomeas del género Coscinodiscus. Se encontraron y estudiaron seis especies del género por medio de microscopía de luz y electrónica (principalmente el microscopio electrónico de barrido). Cada descripción de la especie se acompaña de referencias clásicas, discusión de la variabilidad morfológica y se anota la distribución local y general de cada especie. Coscinodiscus radiatus fue la especie más común y ampliamente distribuída, quizás parcialmente debido a que algunos otros taxa se han propuesto como sinónimos de la especie. Se discuten los problemas comunes en la identificación de las especies de Coscinodiscus y se anotan los caracteres taxonómicos de valor: forma de la valva, presencia de procesos valvares, altura relativa del manto y otros caracteres específicos.

Fase gametofítica del helecho Llavea cordifolia (Pteridaceae).

The development and sexual phase characteristics of Llavea cordifolia, a genus that is monotypic to Mexico, Guatemala and Costa Rica.The spores were collected from Veracruz and Puebla, the culture was in vitro on the basis of gametophyte population growing in petri dishes. Spore germination is of the Vittaria-type, resulting in a uniseriate gametophytic filament of four cells. Prothallial development is of the Adiantum-type. The protallus is cordate-spatulate to cordate and reaches sexual maturity in 60-160 days. The gametangia are of the common leptosporangiate-type.

Se describen las características morfológicas de la fase sexual de L. cordifolia, género monotípico, de distribución en México, Guatemala y Costa Rica. Se recolectaron plantas fertiles de los estados de Veracruz y Puebla, los cultivos se hicieron in vitro observando poblaciones de creciendo en cajas de Petri. La germinación que presenta es tipo-Vittaria, formando un filamento uniseriado de hasta cuatro células. El desarrollo protálico es tipo-Adiantum. Los protalos son cordado-espatulado a cordiformes y alcanzan la madurez sexual de 60-160 días. Los gametangios son del modelo común de los helechos leptosporangiados.

Dinámica de la vegetación y del banco de semillas en un humedal herbáceo lacustrino (Venezuela)

Vegetation and seed banks association with seasonal water depth variations were studied in a herbaceous wetland of a tropical lake in Monagas, Venezuela. The sampling was done in 10x10m² quadrates located at random in two zones of the lagoon. In each sampling four quadrates per zone were analyzed for relative species density, species richness, life forms and water depth. Soil samples were taken simultaneously for ize and composition of the seed banks (seedling emergence method). Soil pH was five. The organic total fraction of the soil varied between 38% and 52%, and the conductivity between 114 and 182 µmhos/cm. 50 species were recorded: 46% perennial herbs, 22% vines, 12% suffrutescents and 10% hydrophytes. The highest species richness was recorded during periods of rain and rain-dry transition. Hymenachne amplexicaulis, Leersia hexandra, Sacciolepis striata and Polygonum acuminatum were among the most important species numerically. The total density of seed bank varied between 5689 and 13936 seedlings/m². In the seed bank there were 58 species: 43% perennial herbs, 22% suffrutescents, 12% vines 9% annual herbs and 9%, hydrophytes. The highest species richness in the seed bank was during periods of dry and dry-rain transition. Cyperus odoratus, Eleocharis interstincta, Ludwigia hyssopifolia, L. lithospermifolia and Polygonum acuminatum had the highest densities. The potential flora of these wetlands included 76 species, but only 33 (43%) were common to the seed bank and the vegetation.

**Temperatura y germinación de las semillas de Dalbergia retusa (Papilionaceae), árbol en peligro de extinción**

The effect of temperature over Dalbergia retusa Hemsl. germination was studied in the laboratory. Seeds were disinfected and placed in Petri dishes for germination at 15, 20, 25, 30, 35, 40, and 45 °C. Germination percentage and the hypocotyl-radicle length were measured after three and five days. The highest germination (85.6%) was obtained at 30 °C. Lower temperatures did not favor germination. Some seeds were able to germinate at 40 and 45 °, a physiological adaptation to hot environments.

Identificación de un compuesto alelopático de Baccharis boliviensis (Asteraceae) y su efecto en la germinación de Trichocereus pasacana (Cactaceae)

The genus Baccharis has a wide distribution in Northwestern arid regions of Argentina. Studies carried out on the spatial distribution of T. pasacana in relation to the available space, show that although beneath B. boliviensis canopy, cacti seeds are abundant, no adult plants are found growing in association to that species in spite of the requirement of a nurse plant for a successfull cacti establishment. Hexane, chloroform and ethyl acetate extracts from B. boliviensis folliage inhibited T. pasacana germination completely.The bioassays were carried out in a germination chamber following a random design, with four replicates by treatment. The chloroform extract was the most effective solvent for extracting the phytotoxic material from the aqueous extracts. The ferrulic acid structure was determined by 13C NMR, ¹HNMR spectra and TLC on silica gel.

El género Baccharis presenta una amplia distribución en regiones áridas del noroeste Argentino. Estudios realizados sobre la distribución espacial de T. pasacana con relación al espacio disponible, mostraron que a pesar de que las semillas del cardón son abundantes bajo la copa de B. boliviensis, no se detectan plantas de cardón creciendo en asociación, a pesar del requerimiento de plantas nodrizas para un establecimiento exitoso del cardón. Extractos acuosos del follaje de B. boliviensis particionado en hexano, cloroformo y acetato de etilo, inhibieron la germinación de T. pasacana. El cloroformo fue el solvente más efectivo para la extracción del material fitotóxico. La estructura del ácido ferrúlico fue determinada por metodos espectroscópicos y TLC sobre gel de sílice.

Hypotensive action of an aqueous extract of Pimenta dioica (Myrtaceae) in rats

The intra-venous (i.v.) hypotensive action of the final aqueous fraction of Pimenta dioica was studied in Spontaneously Hypertensive Rats (SHR). The rats were anaesthetized (sodium pentobarbital 50 mg/kg), the trachea, right carotid artery and jugular vein were cannulated for adequate ventilation, direct blood pressure measurement and intra-venous administration of extracts, solutions and drugs. The arterial line was connected to a pressure transducer (Viggo-Spectramed model P23 XL) and a polygraph (Grass model 7H) and monitored continuously during the first five minutes after plant extract administration and then at 5 and 15 minute intervals for one hour. Responses were taken as the maximum pressure changes observed during this period. Increasing doses of the final aqueous fraction were given i.v. to groups of six SHR each. It produced a dose dependent decrease in blood pressure and the ED50 was 45 mg/kg. To discard that the hypotensive effect of the extracts was due to its ionic composition, a solution containing KCl, NaCl, CaCl2 and MgCl2 equivalent to the ion contents present in a dose of 50 mg/kg of total aqueous extract was injected to Sprague-Dawley rats (SDN) using the same method as described above. It did not produce significant changes in blood pressure. Pharmacological antagonistic studies were done injecting either autonomic ganglion, adrenoceptor, ß adrenoceptor and cholinergic receptor blockers prior to extract administration in SHR rats. Atropine, propranolol and phentolamine did not affect the hypotensive effect of the final aqueous fraction. With hexamethonium (autonomic ganglion blocker) the hypotensive response was diminished in a significant way (p< 0.05). The hypotensive action of the final aqueous extract was not mediated through cholinergic, or ß adrenergic receptors. The extract may posses vasorelaxing activity which could not be evident after autonomic ganglion blockade due to extreme vasodilation present prior to extract administration. Future studies should address the question of a possible direct vasodilating effect of the extracts.

Caracterización fisicoquímica y biológica de la calidad de aguas de la cuenca de la quebrada Piedras Blancas, Antioquia, Colombia

From April to December 1996 a limnological study was carried out in 17 streams near Medellín, in order to stablish their water quality. The area is located in Piedras Blancas Park (6° 8' 20''N, 75° 30' 20''W) SE of Medellín at 2 400 m altitude. Three sampling periods, encompasing wet and dry seasons were selected: April-May, August-September and October-December. For qualitative collection methods hand screen D-net were used. Each station was intensively sampled to collect most macroinvertebrates in all types of habitat. The area sampled in each station was 6 m². Physicochemical variables in general showed small fluctuations along the study; only conductivity and total dissolved solids exhibited significant changes, all related with high precipitation in the wet season. Macroinvertebrate community consisted of 113 genera, 63 families and seven phyla. Trichoptera was the most abundant group. The results indicate that these freshwater ecosystems in the study area present a high water quality corresponding to a oligo-mesotrophic system.

Entre abril y diciembre de 1996, se llevó a cabo un estudio limnológico de 17 quebradas ubicada en el área del Parque Piedras Blancas (6° 8' 20''N, 75° 30' 20''W)localizado al SE de Medellín a 2 400 m de altura. El estudio se realizó en 35 estaciones de muestreo y se establecieron tres períodos de muestreo: el primero entre abril y mayo, el segundo de agosto a septiembre y el tercero de octubre a diciembre de 1996. La finalidad del mismo era establecer la calidad ecológica de las aguas ubicadas en el área del Parque. Para la recolección cualitativa de los macroinvertebrados se utilizaron las redes D-net y de pantalla. El área de muestreo en cada estación fue de 6 m2. Las variables fisicoquímicas mostraron fluctuaciones bajas a lo largo del estudio, excepto la conductividad y los sólidos totales, cuyos cambios estuvieron relacionados con la alta pluviosidad durante el período de estudio. La comunidad de macroinvertebrados encontrada, estuvo conformada por 113 géneros, pertenecientes a 63 familias y siete Phyla, siendo el orden Tichoptera el más abundante. El área de muestreo en cada estación fue de 6 m². El resultado del estudio muestra como la cuenca de la quebrada Piedras Blancas presenta condiciones que pueden clasificarse en términos generales como oligo-mesotróficas.

Population dynamics and spatial distribution of the terrestrial snail Ovachlamys fulgens (Stylommatophora: Helicarionidae) in a tropical environment

The introduced snail Ovachlamys fulgens (Stylommatophora: Helicarionidae) occurs on cultivated land habitats in Costa Rica, where its macrodistribution seems to be limited by annual mean temperature (20 - 27.6°C) and annual precipitation (1 530 - 3 034 and 3 420 - 8 000 mm, with no more than six dry months). This species can be found in litter and on vegetation up to 70 cm tall. Random quadrat field sampling was done in leaf litter and understory plants every three months for a total of five dates in Central Costa Rica. At least 150 plots of 25x25 cm were analyzed on each date. Abundance of living specimens and eggs was positively correlated with (1) litter abundance and depth, (2) litter and soil humidity, (3) relative humidity and (4) early morning temperature (6:30 AM), and negatively correlated with temperature later in the morning (10:00 AM). Besides these factors, living snail abundance was correlated with thickness of the herbaceous vegetation and with the occurrence of Yucca elephantiphes (in litter and understory). Egg abundance was also correlated with the sampling date, apparently because of changes in humidity. The correlation pattern of shell abundance was opposite to that of living specimens. Population size and number of empty shells throughout the year parallel the rainfall pattern. Reproduction takes place between May and November (wet season); and up to 92% of the specimens can be found aestivating between December and April (dry season). Clutch size averages three eggs. The maximum density of living specimens was reached in December (43.41 ind/m²) and the minimum in March (8.30 ind/m²). Shells decompose in an average of five months.

El caracol introducido Ovachlamys fulgens (Stylommatophora: Helicarionidae) habita regiones cultivadas de Costa Rica y su distribución está limitada por temperaturas anuales entre 20 y 27.6ºC y precipitaciones anuales entre 1530-3034 y 3420-8000 mm con no más de seis meses secos. Esta especie habita en la hojarasca y en la cobertura herbácea hasta a 70 cm de altura. Se realizaron cinco muestreos; uno cada tres meses. En cada muestreo se analizaron un mínimo de 150 parcelas aleatorias de 25 x25 cm. Los factores que determinan la abundancia de individuos y huevos fueron la abundancia y profundidad de la hojarasca, la humedad del mantillo y del suelo, y la humedad relativa. Éstos a su vez estuvieron positivamente correlacionados con la temperatura a primeras horas de la mañana (6:30 am) y negativamente con la temperatura a media mañana (10:00 am). Aparte de estos factores, los caracoles tambien estuvieron correlacionados con el grosor de la capa herbácea y con la presencia deYucca elephantipes tanto en el mantillo como en la vegetación. Los huevos tambien se vieron afectados por la época del año, debido a su propiedad higroscópica. La abundancia de conchas se correlacionó únicamente con la temperatura, en patrón contrario al de los los huevos. Tanto la población como la cantidad de conchas siguieron, con un leve retraso, la curva de lluvias de la zona a lo largo del año. La época reproductiva abarca los meses de mayo a noviembre (época lluviosa); y durante los meses de diciembre a abril (época seca) se puede encontrar hasta el 92% de los especímenes estivando. En condiciones naturales la camada promedio tiene tres huevos. Los caracoles vivos tuvieron una densidad máxima de 12.92 ind/m² (en diciembre) y mínima de 2.47 ind/m² (en marzo; estos valores deben multiplicarse por el factor de corrección 3.36). En condiciones experimentales las conchas tardaron intactas dos meses y su descomposición total se produjo en cinco meses en promedio.

Behavior on flowers, structures associated to pollen transport and nesting biology of Perditomorpha brunerii and Cephalurgus anomalus (Hymenoptera: Colletidae, Andrenidae)

Nesting and foraging behavior were studied in Cephalurgus anomalus and Perditomorpha brunerii, two oligolectic bee species on Malvaceae flowers, in the University of São Paulo campus, Ribeirão Preto, Brazil. Bees were monitored on flowers of Sida, Malvastrum, Gaya and Wissadula. Perditomorpha brunerii females collect pollen with the forelegs and abdomen to transport it in short-branched hairs on the hind tibia and metasomal sterna; males patrol flowers and spend the night in closed flowers of Sida cerradoensis and Sida sp. C. anomalus females lean the dorsal region of the body against the petals and collect pollen with the forelegs, accumulating the grains on the mesepisterna before placing them into sparse unbranched hairs on the anterior outer side of the hind tibiae; males patrol and wait for females in flowers, where the copulate throughout the foraging season. Both species nest in the soil among the host plants. P. brunerii bees build solitary nests; whereas in C. anomalus one or more foraging females are associated with an individual nest. The nests, in both species, consist of a descent straight main tunnel and cells arranged singly and horizontally at the end of the branches, which are filled with soil. The efficient foraging behavior, location of the nests among the host plants and scopal setae that allow the transport of large pollen grains in large amounts indicate an intimate association between these two bee species and Malvaceae flowers.

**Fluctuación poblacional de Scolytidae (Coleoptera) en zonas reforestadas con Eucalyptus grandis (Myrtaceae) en Minas Gerais, Brasil**

The size of a population and its variations through time and space are important variables that can be used to determine insect community structure in the field. For this reason ethanolic traps were used to study population fluctuation of Scolytidae species in plantations of Eucalyptus grandis. This study was developed during two years in Antônio Dias, State of Minas Gerais, Brazil where these insects were collected and analyzed in function of temperature and rainfall. Out of 16 Scolytidae species collected those with higher number of individuals were Xyleborus paraguayensis, Xyleborus affinis and Xyleborus ferrugineus (96.27 % of individuals). Temperature and rainfall affected numbers of these insects collected with ethanolic traps. The first two species presented larger populations during periods of low rainfall while X. ferrugineus presented the opposite pattern.

El tamaño de una población y sus variaciones en el tiempo y espacio son variables importantes que permiten determinar el funcionamiento de una comunidad de insectos en el campo. De esta manera, con el uso de trampas etanólicas de intercepción, fue estudiada la fluctuación poblacional de Scolytidae en plantaciones de Eucalyptus grandis. El estudio fue realizado por un período de dos años en la región de Antonio Dias, Minas Gerais, Brasil, donde los insectos fueron recolectados y analizados en función de la temperatura y precipitación. Fueron recolectadas 16 especies de la familia Scolytidae, con predominancia de Xyleborus paraguayensis, Xyleborus affinis y Xyleborus ferrugineus, las cuales representaron el 96.27 % del total de individuos capturados. La temperatura y precipitación fueron las variables que influenciaron directamente en la fluctuación poblacional de estos insecto. Las dos primeras especies presentaron mayores poblaciones durante la época seca, mientras que X. ferrugineus presentó mayor número de individuos en los meses con mayor precipitación.

Burrow characteristics and habitat associations of armadillos in Brazil and the United States of America

We censused and measured armadillo burrows in ten 10 m x 40 m plots in each of four habitat types at a study site in northern Florida and one in the Atlantic coastal rainforest of Brazil. The nine-banded armadillo (Dasypus novemcinctus) was the only species of armadillo found in Florida, but several additional species were present in Brazil. Burrows were more numerous but smaller in Brazil than in the U. S., probably due to the inclusion of burrows dug by the smaller congener D. septemcinctus. In Brazil, burrows were larger and more numerous in swamp and forest habitats than in grassland or disturbed areas, suggesting that D. novemcinctus is found primarily in forests and swamps while D. septemcinctus is located in the other areas. This was supported by data from sightings of live animals. In Florida, burrows were more numerous in hardwood hammocks than in wetlands, fields or upland pine areas, but burrow dimensions did not vary across habitat types. In Florida, armadillos were seen more frequently than expected in hammocks and wetlands and less frequently than expected in fields and upland pine areas. There were also age (juvenile versus adult), sex, and yearly differences in habitat use in Florida. Biomass, abundance, and species diversity of terrestrial invertebrates did not vary significantly between habitat types in Florida, suggesting that habitat associations of armadillos were not influenced by prey availability.

**Helmintos parásitos de la rata Sigmodon hispidus (Rodentia: Cricetidae) de un hábitat estacional y otro perenne en Costa Rica**

The helminthological fauna of the cotton rat, Sigmodon hispidus in a tropical environment varies according to habitat and feeding behavior. Six species of nematodes (Longistriata adunca, Trichostrongylus sigmodontis, Strongyloides sigmodontis, Litomosoides carinii, Monodontus sp. and Protospirura sp.) and two species of cestodes (Hymenolepis diminuta and Raillietina sp.) were found in rats from extensive dry lands in Guanacaste where hot temperatures and heterogeneous diet are the rule. Only two species of nematodes (Longistriata adunca and Angiostrongylus costaricensis) were found in rats collected in a humid pineapple plantation in the Central Plateau (Alajuela) where mild temperatures predominate. A. costaricensis, a metastrongylid of medical importance, was found in 42% of them.

La fauna helmintológica de ejemplares de Sigmodon hispidus capturados en Costa Rica, varió de acuerdo a la región de procedencia. En las ratas provenientes de una zona extensa del Pacífico seco, (Guanacaste) que ofrecía una dieta variada, se encontraron 6 especies de nemátodos y 2 especies de céstodos. En las provenientes de la Meseta Central, (Alajuela) que disfrutaban de una dieta única y abundante, se aislaron solamente dos especies: una de ellas, Angiostrongylus costaricensis, de gran importancia en salud humana, estuvo presente en el 42% de las ratas de esa región.

Seed dispersal by bats in a disturbed area of Southeastern Brazil

Se recolectó semillas de heces de murciélagos en la cuenca del río Piracicaba, Brasil, de julio de 1995 a mayo de 1996. Estos habitan un área con plantas pioneras y de sucesión secundaria tardía. Seis de las 16 especies de murciélagos dispersan plantas de 14 especies y siete familias. La mayor diversidad de dieta correspondió a Artbeus lituratus y Carollia perspicillata y la planta más frecuente fue Cecropia glaziovii. Los murciélagos actúan como dispersores de plantas de la sucesión secundaria inicial.

**Distribución de la garrapata Amblyomma cajennense (Acari: Ixodidae) sobre Bos taurus y Bos indicus en Costa Rica**

Resistance to acaricides in the cattle tick population was surveyed in 532 farms throughout Costa Rica. Samples were collected from bovines (Bos taurus and Bos indicus), in three production systems: dairy, meat and double-purpose. There is an uneven distribution of Amblyomma spp. (including A. cajennense, A. maculatum and A. oblongoguttatum) in the administrative regions in which the country is divided, as well as in ecological zones. Administratively, Amblyomma spp., was 12 times more frecuent (X², p<0.001) in the Central Pacific and Chorotega regions (Pacific coast), than elsewhere. Ecologically, ticks of this genus were more common in the Tropical Humid Forest (33 %) and the Very Humid Montain Forest (18 %). There was at least one sample of Amblyomma in 41% of counties. The most frecuent Amblyomma was A. cajennense. The wide distribution of Amblyomma spp. in very warm places with a marked six months rainy season suggests a potential danger of the substitution capacity of Amblyomma spp., which can also affect public health. The paper also reviews Amblyomma literature in detail.

Se informa sobre la casuística de A. cajennense encontrada sobre B. taurus y B. indicus en Costa Rica en 532 fincas muestreadas a nivel nacional en los diferentes sistemas de producción (leche, carne y doble propósito). Existe desigual distribución Amblyomma spp. (incluidas A. cajennense, A. maculatum, A. inornatum y A. oblongoguttatum) en las diferentes regiones administrativas y en las zonas ecológicas. La presencia de Amblyomma spp. fue 12 veces (X², P<0.0001) mayor en Pacífico Central y Chorotega (costa del Océano Pacífico). Las Z. E. de Bosque húmedo Tropical (33%) y Bosque muy húmedo Premontano (18%), tuvieron la mayor presencia del parásito. Según cantón, se halló al menos un ejemplar de Amblyomma en 25 cantones (41%). A. cajennense es la especie más común. Se detecta una amplia distribución de Amblyomma en lugares cálidos y con una estación lluviosa muy marcada de seis meses. Se incluye una revisión de la literatura sobre el tema de Amblyomma en relación con Costa Rica.

Evaluación rápida de los arrecifes parche de Majagual, Quintana Roo, México

The Majagual patch reef was surveyed 13 days after the indirect effects of hurricane Mitch with 1 m² quadrants and rapid assesment techniques. In comparison with an earlier survey in the Xahuayxol reef, live coral cover was low (11.5% ± 5.2), whereas the cover of filamentous seaweed and old dead coral was high (53.7% ± 27.7 in bath of them). The coral community disturbance may have began several years ago, and low algal turf growth suggests indirect effects of hurricane Mitch, because the surge suspended sediments. Frequency of Favia fragum (Esper) and encrusting coralline algae encounters was higher than for other coral/alga pairs; this suggest a possible effect specificity.

Distribución, abundancia y morfometría de Strombus costatus, Turbinella angulata, Busycon contrarium y Pleuroploca gigantea (Mesogasteropoda: Strombidae, Turbinellidae, Neptuneidae y Fasciolaridae) en Yucatán, México

The distribution, abundance and morphology of four gastropod species are analized for Dzilam de Bravo, Yucatan, Mexico. Samples were taken by a snorkeler from 100 x 300 m plots (31 plots in a 930 000 m² area) between august and september 1994. 896 individuals were examined and the more abundant species were Strombus costatus (44.42%), Turbinella angulata (42.75 %), Busycon contrarium (5.47 %) and Pleuroploca gigantea (3.46 %). Fasciolaria tulipa and Vasum muricatum represented 3.9 % of individuals. We estimated a mean of 0.00096 individuals/m² . The mean shell length of S. costatus was 182 mm (SD±20;N 398), T. angulata 232 mm (SD±52; n=383), B. contrarium 175 mm (SD±48; n=49), and P. gigantea 377 mm (SD±55; n=31).

Se analizó la distribución, abundancia y morfometría de Strombus costatus, Turbinella angulata, Busycon contrarium y Pleuroploca gigantea en Dzilam de Bravo, Yucatán, México. La toma de datos se realizó con buceo libre mediante el método de cuadrantes de 100 m de longitud por 300 m de ancho (31 cuadrantes en un área de 930 000 m²) entre agosto y septiembre de 1994. De 896 individuos, las especies más abundantes fueron Strombus costatus (44.42%) y Turbinella angulata (42.75%), Busycon contrarium (5.47%) y Pleuroploca gigantea (3.46 %). El 3.9 % restante fue de Fasciolaria tulipa y Vasum muricatum. Se estimó una densidad promedio de 0.00096 organismos por metro cuadrado. La longitud promedio de la heliconcha de S. costatus fue de 182 mm (DE+20; n=398), de T. angulata 232 mm (DE+52; n=383), de B. contrarium 175 mm (DE+48; n=49), y de P. gigantea 377 mm (DE+55; n=31).

Tasa de degradación de madera por el perforador de manglar Psiloteredo healdi (Bivalvia:Teredinidae) en el Lago de Maracaibo, Venezuela

The degradation rate of wood substrates by the two species of bivalve molluscan borers, Bankia fimbriatula and Psiloteredo healdi was studied in the mangrove forest of Ana María Campos Peninsula (Lake of Maracaibo, Venezuela). Pine wood substrates were placed in adjacent waters and the rate of infestation and growth (wood consumption) was recorded. The second species was dominant and occurred throughout the entire study (april to october, 1993), but rates of larval invasion and growth of individuals were influenced by the size of the population present. P. healdi is capable of consuming as much 17.1x10-3 g of wood/day.

Con el propósito de evaluar la capacidad de degradar madera de los moluscos bivalvos perforadores de madera en comunidades de manglar, se realizó un estudio en el manglar Ana María Campos, Lago de Maracaibo, Venezuela, utilizando como sustratos bloques de madera de pino. Dos especie de teredos, Bankia fimbriatula y Psiloteredo healdi fueron encontradas en el manglar de la península Ana María Campos, siendo P. healdi la especie dominante. A pesar de estar presente durante todo el período de estudio su capacidad de invadir sustrato varió y la tasa de consumo de madera fluctuó en función del número de individuos por colector. P. healdi fue capaz de consumir hasta 17.1x10-3 g de madera/individuo/día.

**Distribución y abundancia de filosomas de Panulirus (Decapoda: Palinuridae) en el sureste del golfo de California, México**

The spatial and temporal distribution of the stage I phyllosoma larvae of the lobsters Panulirus inflatus and P. gracilis and their relationships to water temperatures and salinities were analyzed from February to December 1989 in the southeastern Gulf of California, Mexico. Three stations were located within the bay of Mazatlan and one was located at the mouth of the Urias system (station one). Two-hundred and eight samples (104 at surface and 104 at bottom) were obtained from 26 horizontal plankton tows. Water temperatures and salinities were measured concurrently. Phyllosoma larvae were most abundant in station one, with total mean densities of 1 206 larvae/1 000 m³ (surface) and 1 196 larvae/1 000 m³ (bottom). Water temperatures ranged from 17.9°C, in February, to 30.2°C, in August, and water salinities ranged from 34.1(0)/00, in August, to 35.0(0)/00, in May. The abundance of phyllosoma larvae was not related to changes in water temperature or salinity, however it was significantly related with the reproductive behavior of adults inhabiting the area. Spatial distribution of phyllosoma strongly depends upon current patterns and tidal cycles.

Se analizó la distribución espacio-temporal de las larvas filosomas de las langostas Panulirus inflatus y P. gracilis y su relación con la temperatura y salinidad, en el sureste del golfo de California, de febrero a diciembre de 1989. Tres estaciones fueron establecidas en la bahía de Mazatlán y una en la boca del sistema de Urías (estación uno). Se obtuvieron 208 muestras (104 de superficie y 104 de fondo) de arrastres horizontales de plancton. Simultáneamente se midieron la temperatura y salinidad del agua. Las larvas fueron más abundantes en la estación uno, con una densidad promedio total de 1 206 y 1 196 larvas/1 000 m³ en superficie y fondo, respectivamente. La temperatura varió de 17.9, en febrero, a 30.2°C, en agosto, y la salinidad de 34.1, en agosto, a 35.00(0)/00, en mayo. La abundancia de larvas no presentó relación con los cambios de temperatura y salinidad (p0.05); mientras que con la conducta reproductiva de las especies de langosta de esta zona estuvo estrechamente relacionada. La distribución espacial de las filosomas está sujeta a las corrientes y a los ciclos de marea de esta región.

La comunidad de copépodos (Crustacea) en los giros a mesoescala en el occidente del Golfo de México (julio, 1995)

The pelagic copepod community of the oceanic area off the Mexican state of Tamaulipas was surveyed in June-July 1995. During the period and area surveyed, two mesoscale gyres, a cyclone and an anticyclone, were detected. The influence of each was related to a particular area. A total of 106 copepod species was determined. Copepod density, diversity, and species richness differed between the areas affected by the cyclone and the anticyclone. The overall density in the two areas was similar, but copepods at the cyclone nucleus were slightly denser than in the anticyclonic nucleus. Diversity and species richness were higher at the relatively more productive cyclone area. Anticyclones are oceanic, oligotrophic systems with a strong Caribbean influence, and the local copepod community structure, dominated by some of the most abundant species in the Caribbean, and with relatively lower diversity and species richness, seemed to agree with the anticyclone features. The copepod fauna of the cyclone, mainly built up by common Gulf water, showed a higher diversity and species richness, and a higher affinity with the fauna of the Gulf. The distributional range of several species is extended in this survey and some are reported herein for the first time in the Gulf of Mexico.

Se estudió la comunidad de copépodos pelágicos en la zona oceánica frente Tamaulipas, Mexico durante junio-julio de 1995. En este periodo se detectaron dos giros a mesoescala, uno ciclónico y el otro anticiclónico; su influencia se relacionó a zonas distintas del área de estudio. Se identificaron 106 especies de copépodos; su densidad, diversidad y riqueza de especies varió entre las áreas afectadas por el ciclón y el anticiclón. La densidad general fue similar en los dos sistemas, pero se encontró mayor densidad en el núcleo del ciclón que en el del anticiclón. La diversidad y el número de especies fue mayor en el ciclón, un sistema más productivo. Los anticiclones son sistemas oceánicos, oligotróficos, con aguas del Mar Caribe. La comunidad de copépodos en este giro, dominada por algunas de las más abundantes especies caribeñas, y con una diversidad relativamente menor, tiene más afinidad con las condiciones anticiclónicas. La fauna del ciclón, formada con aguas comunes del Golfo, mostró mayor diversidad y riqueza de especies así como una afinidad cualitativa mayor con la fauna propia del Golfo. El ámbito de distribución de varias especies se extiende en este estudio; para otras, representa el primer reporte para el Golfo de México.

Cangrejos braquiuros (Brachyura) de la bahía de Maruata, Michoacán, México

A total of 287 specimen of brachyuran crabs were collected in 1990-1991. The specimens belong to 42 species, 34 genera and 14 families. All species represent new records for the coast of Michoacan and include two range extensions: Micropanope cristimanus from Manzanillo to Maruata, and Glyptograpsus impressus from Acapulco to Maruata. The presence of Eupleurodon peruvianus, Epialtus sulcirostris and Mithrax spinipes represents a gap in their distribution. The families with haighest numbers of species were the Mithracidae (7) and Grapsidae (6). The species were sorted out in four groups acording to their zoogeographic affinity: Indopacific (4.76%), Amphiamerican (9.52%), Eastern Pacific (78.57%) and Mexican Pacific (7.14%).

Se hicieron 11 muestreos mensuales, de abril de 1990 a marzo de 1991. Las recolectas se hicieron en forma manual en todos los ambientes: fango, arena, vegetación, laguna, río y en la zona intermareal, hasta una profundidad máxima de seis metros. Se obtuvieron 287 ejemplares de braquiuros agrupados en 14 familias, 34 géneros y 42 especies. Las especies analizadas son nuevos registros geográficos para las costas de Michoacán, además de dos ampliaciones de ámbito: una, Micropanope cristimanus hacia el sur desde Manzanillo, Colima; la otra, Glyptograpsus impressus, hacia el norte desde Acapulco, Guerrero. Se proporciona una nueva localidad intermedia para tres especies con distribución disyunta, Eupleurodon peruvianus, Epialtus sulcirostris y Mithrax spinipes. Las familias con mayor número de especies son la Mithracidae (7) y Grapsidae (6). Las especies fueron agrupadas en cuatro grupos biogeográficos: Indopacífico (4.76%), Anfiamericano (9.52%), Pacífico este tropical (78.57%) y Pacífico mexicano (7.14%).

Reproducción y desarrollo de Ecteinascidia turbinata (Ascideacea: Perophoridae) en Cuba

The reproduction of Ecteinascidia turbinata was studied in Punta del Este, Isla de la Juventud, Cuba. Gonadal development of 4 606 zooids from 30 colonies was studied in six localities by monthly samples from June 1994 through May 1995. In addition, from August to November 1997, the regenerating capacity of the colonies was assessed. Number and diameter of oocytes, embryos and larvae were measured in 21 zooids (17-23 mm long). Five stages of gonad development are described: juvenile, immature, mature, in larval release and in reabsorption. The zooids reach 27 mm in length. Immature zooids may exceed 60% of the total population throughout the year and prevail in most length classes. Minimum size for mature zooids was 6.7 mm, but more than 50% of mature and at larval release zooids measured 19-20 mm. Sexual reproduction occurs from September through July with a peak in April-May. Asexual reproduction occurs year-round, but more intensely during the summer, especially in August. After the spawning and reabsorption of all zooids in a colony, the following cycles of generation-degeneration of the colony repeat approximately every 40 days.

Se presentan algunas características de la reproducción de Ecteinascidia turbinata en Punta del Este región suroeste de Cuba. Para conocer el desarrollo gonadal de la especie, se analizaron 4 606 zooides provenientes de 30 colonias, distribuidas en seis estaciones, que se muestrearon mensualmente de junio de 1994 a mayo de 1995. De agosto a noviembre de 1997 se realizaron algunos muestreos para determinar la capacidad de regeneración de las colonias. Se establecieron cinco estadios de desarrollo gonadal: Juveniles, Inmaduros, Maduros, en Liberación larval y en Reabsorción. Los zooides alcanzan hasta 27 mm de largo. La talla mínima de maduración sexual de los zooides fue de 6.7 mm, pero más del 50% de los maduros y en fase de liberación de larvas tienen entre 19 y 20 mm de largo. Los zooides inmaduros predominan en la mayoría de las clases de largo y constituyen más del 60% del total durante casi todo el año. Ecteinascidia turbinata se reproduce de forma sexual de septiembre a julio, con un máximo en abril-mayo y asexualmente durante todo el año, aunque con mayor intensidad durante el verano y principalmente en el mes de agosto. En 21 zooides con largos entre 17 y 23 mm, se contaron y midieron los oocitos, embriones y larvas. Después de producido el desove y la reabsorción de todos los zooides de una colonia, los siguientes ciclos de generación-degeneración de la colonia se repiten aproximadamente cada 40 días.

**Fecundity of Sarotherodon galilaeus (Pisces: Cichlidae) in the Opa reservoir, Ile-Ife, Nigeria**

The fish Sarotherodon galilaeus was collected in Opa reservoir, Obafemi Awolowo University, Ile-Ife, Nigeria. Sampling began in January, 1992 and extended until March, 1994. The fishing methods employed for collecting the 853 specimens were gillnetting and castnetting. Sex ratio was approximately 1:1 (male: female). Length at maturity was 12.5 cm (males) and 11.7 cm (females). The fecundity was 1 048 ± 785 (604-2173, n= 117) with an egg diameter of 2.49 ± 1.81 (1.0 - 4.5, n = 117) mm. The gonado-somatic index was 0.33 ± 0.21 (0.09 - 1.34, n = 275) (males) and 1.88 ± 1.01 (0.33 - 6.19, n = 282) (females). The species breeds year-round (mature specimens occurred in samples collected throughout the 27-month study period). This fish is a biparental mouth booder.

**Reproduction, distribution and abundance of Bothus constellatus (Pisces: Bothidae), in the Gulf of Tehuantepec, Mexico**

A total of 3 593 individuals of Bothus constellatus was captured during five oceanographic cruises carried out in the Gulf of Tehuantepec, Mexico. Its distribution, abundance, and reproduction patterns were stated by means of the analysis of the population parameters (i.e. density, biomass, weight and size average, visceral and gonadosomatic index, and maturity stages). B. constellatus is a typical demersal marine species, because it does not occur in estuaries, but occurs near to them on the continental shelf. It is distributed in the Gulf of Tehuantepec in depths lesser than 60 m, with high abundance around the 40 m isobath, and in front of Mar Muerto Lagoon. During January and May the biomass and density were high. The size at first maturity of females is 101 mm total length, and maturation occurs first in zones influenced by estuarine processes. Reproduction and recruitment were detected in all the collections.

Ictiofauna juvenil de fondos blandos durante la transición de "secas" a lluvias en la costa pacífica de Colombia

Based on ichthyoplancton research along the southern Pacific coast of Colombia, which revealed high concentrations of fish larvae in this area, a juvenil fish survey was conducted in shallow waters (<10 meter water depth) during the transition period from dry to wet season (July 21 to July 31, 1994). The twelve sampling stations, were distributed in front of the four main of this coastline, where the highest concentrations of juvenile fish were expected. At each sample station, three 15 min oblique hauls were conducted every 8 hours using a bottom trawl for juvenile fish of 4 mm mesh size; 53 species in 20 families were identified (21 not known as adults in the area). They were distributed as follows: Sciaenids (11), Ariids (7), Pristigasterids (6), Engraulids (6), Carangids (5), Clupeids (2), Soleids (2), Batrachoidids (2), Tetraodontids (2), Urolophids (1), Polynemids (1), Synodontids (1) and Taeniopedids (1). This ichthyofauna is common in open tropical estuaries. Abundances and biomass were 0.35 ind./m³ and 1.61 g/m³ respectively, higher than in other tropical shallow water systems. The niches of the 25 species whose abundance (A) and biomass (B) contributed 97.5% and 93.3% respectively to the total catches were: (1) pelagic-neritic (53% A, 34% B); (2) demersal-pelagic (18% A, 28% B); (3) demersal (22% A, 23% B) and (4) benthic (8% A, 15% B). The Shannon-Weaver diversity index in the four subareas ranged from 0.89 to 1.1, within the range reported for other tropical American estuarine systems. An ordination analysis (non-metric Multi-Dimensional Scaling, MDS) of the data revealed significant differences in the species composition between day and night and an important association among some species. Station position, tides and environmental parameters did not markedly influence species composition. It is concluded that: (1) The area surveyed represents an important nursery and growth habitat for juvenile fish of many species that are more common as adults over soft bottoms in deep waters of the continental shelf; (2) this shallow soft bottom fish community is clearly separated from those species inhabiting intertidal salt marshes, interior bays and mangrove areas; and (3) some of the fish species commonly living in rocky and reef habitats in adult stages, spend their juvenile stage over shallow water soft bottoms. These results confirm a rather strong niche separation between juvenile and adults fish species stages in tropical waters.

En base a mayores concentraciones de plancton encontradas en la parte sur de la costa pacífica colombiana, se colectó su ictiofauna juvenil en aguas someras (<10 m de profundidad) en la época de transición de secas a lluvias, frente a sus cuatro estuarios más importantes. El área de estudio comprendió 12 estaciones. En cada estación, se efectuaron entre el 21 y el 31 de julio de 1994 tres arrastres oblicuos de 15 min de duración, con aprox. ocho horas de diferencia, utilizando una red para juveniles de peces de 4 mm de ojo de malla en el copo. En total fueron capturadas 53 especies pertenecientes a 20 familias (21 de ellas no registradas hasta ahora como adultos en la zona). Estas se distribuyeron como sigue: Sciaenidae (11), Ariidae (7), Pristigasteridae (6), Engraulidae (6), Carangidae (5), Clupeidae, Soleidae, Batrachoididae, Tetraodontidae (2 especies cada una), Bothidae, Cynoglossidae, Ophidiidae, Haemulidae, Ephipidiidae, Torpedinidae, Urolophidae, Polynemidae, Synodontidae y Taeniopedidae (1 especie). Esta ictiofauna es característica de estuarios abiertos. Las abundancias y biomasas medias fueron 0.35 Ind./m³ y 1.61 g/m³ respectivamente, valores comparativamente altos para aguas costeras tropicales. El agrupamiento de las 25 especies cuyas abundancias (A) y biomasas (B) representaron respectivamente 97.5% y 93.3% del total de las capturas, de acuerdo a sus nichos ecológicos, arrojó la siguiente composición: 1. Pelágico-neríticas (53% A; 34% B) 2. Demersal-pelágicas (18% A; 28% B) 3. Demersales (22% A; 23% B) y 4. Bentónicas (8% A; 15% B). El índice de diversidad de Shannon-Weaver en las cuatro subáreas, varió entre 0.89 y 1.1 encontrándose dentro del rango reportado para otros estuarios americanos. La ordenación de los datos de las capturas (escalamiento multidimensional no métrico, NMDS) reveló diferencias día/noche en la composición específica y determinadas asociaciones de especies. La ubicación geográfica de las estaciones, la marea y los parámetros ambientales no jugaron un papel significativo en su distribución. Se concluye que: 1) el área estudiada representa una zona de crecimiento de una ictiofauna adulta típica de fondos blandos de aguas más profundas de la plataforma continental; 2) esta comunidad está claramente separada de la comunidad de juveniles de peces eurihalinos de fondos blandos típicos de charcos intermareales, manglares y bahías interiores y 3) algunas especies cuyos estadíos juveniles transcurren sobre fondos blandos de las aguas someras, migran como adultas a hábitats rocosos o coralinos. Lo anterior confirma una mayor separación por nichos entre juveniles y adultos, para las especies de peces de aguas tropicales.

Earthworms as bio-indicators of metal pollution in dump sites of Abeokuta City, Nigeria

Metal concentrations (Zn, Pb, Mn, Cu, Cd and Cr) and contents were measured in earthworms (Libyodrilus violaceus) and soil samples from three non-contaminated sites and ten dump sites located in Abeokuta, Nigeria. Samples from control sites show (in general) levels of metals to be higher in earthworms than in soil samples, as shown by the mean concentrations, (earthworms-soil: - Zn:7.02, 6.74, Pb:5.04, 4.94, Mn 10.54, 10.41, Cu:1.03, 1.60., Cd: 0.80, 0.81 and Cr:0.55, 0.49 µg/g) while for samples from dump sites, irrespective of the degree of pollution, the ratio of metal concentration in earthworms to soil samples were less than unity with the exception of Cd and Cr. The availability of metals in soils was also co-determined by the soil pH and soil organic matter which accounted for the trend of metal concentration at the various dump sites. For the control sites, the pH ranged from 5.40 - 6.74 and soil organic matter from 3.25% to 3.40%, while for the dump sites, values of 7.44-10.10 and 5.79% - 7.59% were obtained for soil pH and soil organic matter respectively. The metal ion concentration in both soil and earthworm samples followed the trend Pb > Zn > Mn > Cu > Cr > Cd. Dump sites with high levels of Pb were located by roadsides of busy highways.

New species and distribution records of Mesoamerican Ateuchus (Coleoptera:Scarabaeidae)

This paper describes three new species of Ateuchus for Mesoamerica. The new taxa are: A. gershensoni (copulatory hooks subequal in size and spinelike), A. perezvelai (small size; frons very convex; one very big copulatory hook and two small spine-like ones associated with a spiny fascies) and A. perpusillus (anterior pronotal margin incomplete; small and compact copulatory hooks, associated with a spiny fascies) from southern Mexico, Guatemala and Honduras. Redescriptions are also given for A. chrysopyge (Bates) (big size; copulatory hooks, one big, a spine-like medium-sized one and a hook-like small one) and A. guatemalensis (Bates) (pronotum punctured; anterior pronotal margin almost effaced; pygidium convex; copulatory hooks, two small and compact and one very thin and curved). New country and distributional records are also registered for Mexico, Guatemala, Belize, Honduras and El Salvador. Distribution map, internal sac of aedeagus illustrations and photographs of dorsal habitus are included, as well as drawings of the dorsal habitus of the three new species. The present work clarifies the situation of the genus in Mesoamerica and updates knowledge of the group in Mexico.

Este trabajo describe tres nuevas especies de Ateuchus para Mesoamérica. Los nuevos taxa son: A. gershensoni, A. perezvelai y A.perpusillus del sur de México, Guatemala y Honduras. Se incluyen redescripciones de A. chrysopyge (Bates) y A. guatemalensis (Bates). Se citan nuevos registros de países y de distribución para México, Guatemala, Belice, Honduras y El Salvador. Se incluyen mapas, ilustraciones del saco interno del edeago y fotografías del hábito dorsal, así como ilustraciones del hábito dorsal de las tres nuevas especies. Este estudio representa una extensión del trabajo originalmente realizado para los Ateuchus de Norteamérica (Kohlmann 1984). El trabajo clarifica la situación del género en Mesoamérica. También actualiza el conocimiento del grupo para México al reportar la presencia de cuatro especies más (dos nuevas, gershensoni y perezvelai; y dos nuevos registros para el país, chrysopyge y guatemalensis) y así incrementar el número de especies conocidas de ocho a doce.

Odonata of Costa Rica: Diversity and checklist of species

An updated list of the Odonata of Costa Rica is presented containing 268 species. Since the last published list for the country, 41 additional species have been reported. The country is the best studied in Central America. The most species-rich families are Libellulidae, Coenagrionidae, Gomphidae, and Aeshnidae, together comprising ~75% of the total fauna. Most species in the country are also found in South America, indicating a tendency for wide ranges rather than endemism. However, about a fifth of the species appear to be endemic to the Costa Rica-Panama region. Estimates of the range of the proportion of total world species occurring in Costa Rica lead to predictions of a range of 5600-9000 species of Odonata worldwide.

Se presenta una lista actualizada de los Odonata de Costa Rica, la cual contiene 268 especies. A pesar de ello, se espera que algunas especies más se agreguen en el futuro. En comparación con trabajos anteriores, el número de especies para Costa Rica se incrementó en 41, siendo el país mejor estudiado de Centro América. Las familias con mayor diversidad de especies son: Libellulidae, Coenagrionidae, Gomphidae, y Aeshnidae, que en conjunto representan ~75% del total de la fauna de Odonata en Costa Rica. La mayoría de las especies del país también se encuentran en Sur América, lo que indica una inclinación hacia ámbitos de distribución amplios, mas que altos grados de endemismo. Sin embargo, el 18% de las especies es aparentemente endémico de Costa Rica y Panamá. Con base en los números aquí presentados, se esperaría que la fauna mundial de Odonata se encuentre dentro del ámbito de 5600 a 9000 especies.

**Histopathological characterization of nephritides in the brown capuchin monkey, Cebus apella (Primates: Cebidae)**

The renal lesions are of special importance in the captive primates. The most commonly pathologies are: pyelonephritis, nephrocalcinosis, glomerulonephritis, congenital malformations, hydronephrosis and functional diseases. We report the histopathological study of renal lesions of five cases of deaths in Cebus apella (Primates) of the Argentinean Primate Center. The ages of the monkeys were from 4 months to 15 years old. Microscopically, we have observed principally acute diffuse proliferative glomerulonephritis, hilar mesangio proliferative glomerulonephritis, extracapilar glomerulonephritis with crescents, chronic interstitial nephritis and chronic pyelophritis.

**Foraging over army ants by Callithrix aurita (Primates: Callitrichidae): Seasonal occurence?**

Efecto de las actividades humanas sobre la diversidad de mamíferos terrestres en un gradiente altitudinal

The effect of human activity on terrestrial mammals was studied with footprint counts in Guanacaste, Costa Rica (10°30'N, 85°40'W) in February 1998 (in fifty 2 m² quadrats). The most common species were Canis latrans, Didelphis marsupialis, Odoicoleus virginianus, Dasyprocta punctata and Tapirus bairdii. No stastically significant association was found between humna activity and mammal frequency in the footprint counts.

Pisidia magdalenensis (Crustacea: Porcellanidae) commensal of the diogenid hermit crab Petrochirus californiensis (Decapoda: Diogenidae).

Attempted predation on Brazilian rabbit (Sylvilagus brasiliensis **- Lagomorpha: Leporidae) by tayra (Eira barbara - Carnivora: Procyonidae)**