Resumo A rádula em todas as espécies de melongeninae é bastante uniforme e caracterizada por dentes laterais bicúspides com cúspides fortemente curvas e raquidianas sub-retangulares, portando geralmente 3 cúspides. O objetivo do presente estudo foi descrever a rádula de 2 populações de Pugilina cochlidium usando SEM. A rádula em 2 espécies mostra-se como um tipo rachiglossate mostrando a fórmula radular de 1 + R + 1. A primeira população tem o dente central largo com cúspides afiadas igual em comprimento, emana da margem posterior da base do dente. Os dentes laterais possuem 2 cúspides longas, pontiagudas, pontiagudas e dobradas em direção ao dente raquidiano. Enquanto a segunda população, o dente central estreito com cúspides afiadas igual em comprimento, emana da margem posterior da base do dente. Os dentes laterais têm 2 cúspides largas, longas, pontiagudas, pontiagudas e dobradas em direção ao dente raquidiano. Eles são tipicamente em forma de foice com ampla base forte. Em ambas as populações, o dente raquidiano é subquadrado com 3 grandes cúspides no meio, mas na segunda população a base do ráquidiano é côncava enquanto na primeira população é reta. No presente estudo, a mediana da raquidiana da segunda população apresenta uma ampla região basal quando comparada à primeira. Esta observação semelhante foi feita em Chicoreus virgineus ponderosus e Siratus virgineus ponderosus. No presente estudo, uma vez que 2 populações exibem o mesmo padrão de rachiglossato generalizado, ele não oferece muito espaço para o diagnóstico sistemático abaixo do nível genérico.

Abstract Radula in all melongeninae species is rather uniform and characterized by bicuspid lateral teeth with strongly curved cusps and sub rectangular rachidians, bearing usually 3 cusps. The aim of the present study was to describe the radula of 2 Pugilina cochlidium populations using SEM. The radula in 2 species proves itself as a rachiglossate type showing the radular formula of 1 + R + 1. The first population hasthe central tooth wide with sharp cusps equal in length, emanate from posterior margin of tooth base. The lateral teeth have 2 cusps and are long, sharp, pointed and bent towards the rachidian tooth. Whereas the second population, the central tooth is narrow with sharp cusps equal in length, emanate from posterior margin of tooth base. The lateral teeth have 2 cusps and are broad, longer, sharp, pointed and bent towards the rachidian tooth. They are typically sickle shaped with broad strong base. In both populations the rachidian tooth is subquadrate with 3 big cusps in the middle, but in the second population the base of the rachidian is concave while in the first population it is straight. In the present study the median rachidian of the second population, has a broad basal region when compared to first. This similar observation has been made in Chicoreus virgineus ponderosus and Siratus virgineus ponderosus. In the present study, since 2 populations exhibit the same generalized rachiglossate pattern it does not offer much scope for systematic diagnosis below generic level.

Abstract Age and growth of two populations of Pugilina cochlidium were studied. to address the lack of basic information on the growth rates and the size at sexual maturity of organism in a commercially harvested area, which will be important in considering the size limits to conserve this resources in future. In the present study the results showed more or less similar growth patterns in the males and females of two populations of Pugilina cochlidium. The age and growth estimation of these two populations of Pugilina cochlidium were completed using several methods and the outcome of one method will act as a check and control over the other using the FISAT 1 software. The values of asymptotic length (Lα) values obtained in the present study using various methods did not vary greatly. Lα values obtained for the first population of Pugilina cochlidium was 95.55 mm for males and 106.05 mm for females and the growth rate (K) for males (0.588 yr-1) and females (0.620 yr-1) was given by k-scan routine in ELEFAN. Similarly, the values of asymptotic length (Lα), obtained for second population of Pugilina cochlidium, was 96.15 mm for males and 106.05 mm for females and the growth rate (K) for males (0.540 yr-1) and females (0.950 yr-1) was given by k-scan routine in ELEFAN.

Resumo A idade e o crescimento de duas populações de Pugilina cochlidium foram estudados. abordar a falta de informações básicas sobre as taxas de crescimento e o tamanho na maturidade sexual do organismo em uma área comercialmente colhida, o que será importante considerando os limites de tamanho para conservar esses recursos no futuro. No presente estudo os resultados mostraram padrões de crescimento mais ou menos semelhantes nos machos e fêmeas de duas populações de Pugilina cochlidium. A idade e a estimativa de crescimento destas duas populações de Pugilina cochlidium foram completadas usando vários métodos e o resultado de um método funcionará como uma verificação e controle sobre o outro usando o software FISAT 1. Os valores de comprimento assintótico (Lα) obtidos no presente estudo usando vários métodos não variaram muito. Os valores de Lα obtidos para a primeira população de Pugilina cochlidium foram de 95,55 mm para machos e 106,05 mm para fêmeas e a taxa de crescimento (K) para machos (0,588 yr-1) e fêmeas (0,620 yr-1) foi dada pela rotina k-scan na ELEFAN. Similarmente, os valores de comprimento assintótico (Lα), obtidos para a segunda população de Pugilina cochlidium, foram 96,15 mm para machos e 106,05 mm para fêmeas e a taxa de crescimento (K) para machos (0,540 anos) e fêmeas (0,950 anos). 1) foi dado pela rotina de k-scan na ELEFAN.

BACKGROUND: Brachygalaxias bullocki (Regan, 1908) is a small-sized freshwater fish species (41 to 46 mm) and endemic to Chile. Its biology has still various knowledge gaps, and its distribution range has been reduced in the last decade due to human intervention. FINDINGS: In this article, for the first time, its presence in forested wetlands of Chile (38°52' to 39°02' S) is documented. The presence of this species in these ecosystems is restricted to wetlands with permanent water regime and depths ranging from 15.7 to 83.5 cm. CONCLUSIONS: The physicochemical habitat conditions show important seasonal variations, suggesting that B. bullocki is resistant to a wide range of temperatures, as well as different levels of dissolved oxygen and conductivity.

The presence of alloctone bacteria isconsidered as one of the more important biological pollutants of water bodies, existing one close relation between the fecal contamination indicators and the existence of urban and industrial zones. In the present study we utilized indicators of fecal contamination (coliforms and streptococci) and the coliform/streptococci index (FC/FE) for determine the origin of fecal pollution in two water bodies of Temuco, Northern Campus at north surrounding of Temuco, and Rucamanque source that is located in a rural zone. It utilized the multiple assays number for obtain the bacteria more probable number in 100 mi of water sample. It was done the correlations between microbiological indicators and physic-chemical variables. The results indicate that both sites have low fecal contamination. It was reported important correlation between fecal coliforms, temperature and pH, but negative correlations with dissolved oxygen. The index (FC/FE) was correlated only with dissolved oxygen. The temperature would have an important regulator role in the coliform growth, whereas the fecal streptococci have high densities at low values of temperature, conductivity and dissolved oxygen. The origin of microbiological pollution was related with the antrophogenic intervention in both studied sited, human origin in Northern Campus, and mixed origin in Rucamanque source. It was suggest the use of index as first approach for identify the origin of fecal pollution.

La presencia de bacterias alóctonas es considerada uno de los contaminantes biológicos más importantes de los sistemas acuáticos, existiendo una estrecha relación entre los indicadores de contaminación fecal y la existencia de centros urbanos e industriales. Se utilizaron indicadores de contaminación fecal (coliformes y estreptococos fecales), y el índice coliformes/estreptococos fecales para determinar la fuente de contaminación fecal en dos cuerpos de agua de la comuna de Temuco, Laguna Campus Norte, situada en zona urbana y bocatoma Rucamanque, ubicada en un sitio rural. Se utilizó la técnica de tubos multiples para obtener el número más probable de bacterias en 100 mi de agua. Se efectuaron correlaciones entre los indicadores microbio lógicos y variables fisicoquímicas. Los resultados indican que ambos sitios presentaron baja contaminación fecal. Se reportan importantes correlaciones entre coliformes fecales, temperatura y pH. Los estreptococos fecales exhibieron altas correlaciones con la temperatura y pH, pero negativas con el oxígeno disuelto. El índice CF/FE se correlacionó únicamente con el oxígeno disuelto. La temperatura jugaría un rol regulador en el crecimiento de los coliformes, en cambio los FE, presentan mayores densidades a menores valores de temperatura, pH, conductividad y oxígeno disuelto. La fuente de contaminación microbio lógica se relacionó con la intervención antrópica presente en los sitios, origen humano en laguna Campus Norte y origen mixto en bocatoma Rucamanque. Se recomienda el uso del índice como primera aproximación para identificar el origen de la contaminación fecal.

The Torres del Paine National Park is characterized by the presence of numerous water bodies, such as large oligotrophic lakes, small lakes with fishes, and small shallow ponds. The published studies, based on data obtained between 1989 and 1991, indicates that species richness is inversely related with the conductivity and directly related with chlorophyll concentration. The present study consisted of an analysis from unpublished data obtained during 2001, where it was also considered the dissolved organic carbon concentration as a potential protector against natural ultraviolet radiation penetration, reported during the last two decades. The results were similar to the first studies on the role of chlorophyll concentration and conductivity as regulators of species richness, and in the present study was denoted that the species richness was directly related with dissolved organic carbon concentration. The maximum species richness was observed in mesotrophic status, low conductivity and high dissolved organic carbon concentration. These results agree partially with co-occurrence null model analysis.

El Parque Nacional Torres del Paine se caracteriza por la presencia de una serie de ecosistemas lacustres tales como grandes lagos ultraoligotróficos, lagos pequeños con peces, y lagunas pequeñas superficiales. Los estudios publicados sobre la base de información obtenida entre los años 1989 y 1991, indican que a la riqueza de especies está indirectamente relacionada con la conductividad y directamente relacionada con la concentración de clorofila. El presente trabajo consistió en un análisis de información de algunos lagos del parque sin publicar, obtenida el año 2001, donde además se consideró concentración de carbono orgánico disuelto como un agente protector contra el incremento de la radiación ultravioleta natural reportado en las últimas dos décadas. Los resultados mostraron tendencias similares a las observadas en los primeros registros, donde se observó un rol de la concentración de clorofila y la conductividad en la riqueza de especies; a lo que se agrega ahora la concentración de carbono orgánico disuelto, la cual estaría directamente relacionada con la riqueza de especies. La máxima riqueza de especies se observa en condiciones de mesotrofía, baja conductividad y alta concentración de carbono orgánico disuelto. Estos resultados concordarían parcialmente con la aplicación de modelos nulos de asociaciones de especies que indican la existencia de factores reguladores.

Chilean Patagonia has numerous unpolluted terrestrial and aquatic ecosystems, containing many unpolluted and pristine lakes and ponds. Published and unpublished information collected between 1989 and 1990 in lakes and ponds within Torres del Paine National Park, an unpolluted and pristine protected área in Southern Chile (51°S), was analysed in this study. A principal component analysis (PCA) was applied using mainly chemical parameters, zooplankton species richness and biomass. It was found that the cations (Ca, Na, Mg) chloride, seston and chlorophyll concentrations together with zooplankton biomass and zooplankton species richness were the main contributing variables to the derived model. According to this model, the following groups were observed: l st group- deep oligotrophic lakes with low zooplankton biomass and low species richness; 2nd group - small mesotrophic lakes and ponds with modérate conductivity, zooplankton biomass and species richness. This latter group included small ponds with high nutrient and chlorophyll concentrations. A nuil model for species co-ocurrence was applied. The results in two of three simulations denoted that species associations are not random, which would agree with the PCA results. These results showed that oligotrophy and low ionic concentrations, and probably fish presence, are important regulatory factors in zooplankton community structure. These explain the similar patterns observed between Argentinean and Chilean Patagonian lakes.

La Patagonia de Chile posee muchos ecosistemas acuáticos sin contaminación, dentro de estos ecosistemas hay muchos lagos y lagunas prtstinos. En este estudio, se analizó información colectada entre los años 1989 y 1990 (sin publicar y sin publicar) sobre lagos y lagunas del Parque Nacional Torres del Paine, un área sin contaminar en el sur de Chile (51° S). Se aplicó un análisis de componentes principales considerando parámetros qutmicos, riqueza de especies zooplanctónicas y biomasa. Los resultados denotaron que las concentraciones de cationes (Ca, Na y Mg), cloruros, seston y clorofila, junto con biomasa de zooplancton y riqueza de especies zooplanctónicas fueron las principales variables que contribuyeron al modelo obtenido. Según este modelo, se observaron los siguientes grupos: un primer grupo conformado con lagos oligotróficos con baja biomasa de zooplancton y baja riqueza de especies; un segundo grupo conformado por pequeños lagos mesotróficos con conductividad moderada, biomasa y riqueza de especies zooplanctónicas moderadas, dentro de este grupo hubo además pequeñas lagunas con altas concentraciones de nutrientes, clorofila y alta biomasa y riqueza de especies zooplanctónicas. Se aplicó un modelo nulo para co-ocurrencia de especies, que mostró que las asociaciones de especies no son aleatorias, lo que se demostró en dos de las tres simulaciones, lo cual concordarta con los resultados del análisis de componentes principales. Estos resultados revelartan que la oligotrofta y las bajas concentraciones de iones sertan los principales factores reguladores de la estructura de la comunidad zooplanctónica, y probablemente la presencia de peces, lo cual explicarta los patrones similares observados para lagos de la Patagonia de Argentina y Chile.

The zooplankton assemblages in water bodies of central and southern Chilean Patagonia, is characterized by high endemism and a relative low species richness, the main regulator factor would be the conductivity and trophic status of their habitats. The aim of the present study was analyze published and unpublished information about crustacean zooplankton in central and southern Chilean Patagonian lakes and ponds (44 - 53g S). To these data was applied the species / genera ratio, and also, a null mo-del analysis for species co-occurrence, based in a presence-absence species matrix, for determine the existence of random factors as regulator factors of species associations. Finally, it was applied a Jaccard index for determine potential similarities in species associations for site. The results revealed low species number in large and deep lakes, whereas in small shallow permanent and ephemeral ponds had high species number, and low value in the species genera / ratio. The results of null model revealed the absence of random factors as regulators of species associations for two of three simulations, and the results of Jaccard index denoted the existence of three main groups based in the species associations of sites. These results agree with ecological information for southern Patagonia. Ecological and biogeographical topics are discussed.

Los ensambles zooplanctónicos en cuerpos de agua de la zona centro y sur de la Patagonia chilena se caracterizan por su alto endemismo y un relativo bajo número de especies lo cual se debería principalmente a la oligotrofía y niveles de conductividad de estos ambientes. El objetivo del presente trabajo consistió en analizar información publicada y sin publicar sobre crustáceos zooplanctónicos en lagos y lagunas de la zona central y sur de la Patagonia (44 - 53g S). A estos datos se les estimó la razón especies / género, y se aplicó un modelo nulo basado en co-ocurrencia de especies mediante una matriz de presencia y ausencia de especies, con la intención de determinar ausencia de factores reguladores de las asociaciones de especies. Dentro de este mismo contexto, se aplicó un índice de Jaccard para determinar potenciales similitudes entre las asociaciones de especies por sitio. Los resultados revelaron que hubo un bajo número de especies en lagos grandes y profundos, mientras que en lagunas pequeñas someras, ya sea temporales o permanentes, hubo un alto número de especies, y un bajo valor de la razón especies género. Los resultados del modelo nulo revelaron la ausencia de factores aleatorios como reguladores de las asociaciones de especies en dos de tres simulaciones. Los resultados del índice de Jaccard indicaron la existencia de grupos marcados de sitios sobre la base de las especies reportadas en cada uno. Estos resultados concordarían con información ecológica para el sur de la Patagonia. Se discutieron tópicos de ecología y biogeografía.

Se comparó el crecimiento individual expresado en largo total, de dos poblaciones de A. franciscana (Utah, Estados Unidos, y Yape, Chile) y A. persimilis (Salinas de Hidalgo, Argentina) cultivadas a partir de quistes bajo condiciones controladas (24°C, agua de mar 35 g/l, alimentación con Chaetoceros calcitrans). Se encontraron diferencias significativas en todos los estadios analizados entre las poblaciones de A. franciscana de Utah y A. persimilis, mientras que entre A. persimilis y A. franciscana de Yape, hubo similitudes sólo en dos estadios, y A. franciscana de Utah y Yape registraron similar tamaño corporal para todos los estadios analizados. Las adaptaciones a los hábitats podrían explicar estos resultados.

Growth (length), was compared in A. franciscana populations from Utah, United States of America, and Yape, Chile, and A. persimilis (population from Salinas de Hidalgo, Argentina), cultured under controlled conditions (24°C, seawater 35 g/l, feeding with Chaetoceros calcitrans). There were significant differences among all stages of A. franciscana (Utah) and A. persimilis, whereas we found significantly differences only in two stages of A. persimilis and A. franciscana (Yape); both A. franciscana had similar total lengths in all stages analyzed. Habitat adaptations could explain these results.