Cristina Damborenea

Ecosystem engineering impact of Limnoperna fortunei in South America

Limnoperna fortunei, or golden mussel, has invaded aquatic ecosystems in the Americas following it introduction from Southeast Asia. It is not only an aggressive invasive species, it is also a very effective ecosystem engineer, altering both ecosystem structure and function, and causes great ecological and economic impacts. This paper describes its impact as an ecosystem engineer (on benthic communities and the water column). A review of the existing scientific literature is presented, and the impact and the mechanisms by which the golden mussel modifies, maintains, and creates new environmental conditions in the invaded South American inland freshwater environments are analyzed. Understanding the ecosystem engineering roles of L. fortunei is important for its management and/or control in the invaded areas, and in cases of future invasions.

New Species of Gieysztoria (Platyhelminthes, Rhabdocoela) from Peruvian Amazon Floodplain with Description of their Stylet Ultrastructure

Abstract The free-living Platyhelminthes of the Amazon basin are poorly known. Presently only four turbellarian species have been mentioned from the Amazon river, a fact that confirms the lack of information on this kind of faunas in this huge basin. Three new species of Gieysztoria from Amazonian floodplain in Peru are described herein: G. chiqchi n. sp., G. kasasapa n. sp. and G. sasa n. sp. The samples were taken in the Pacaya-Samiria National Reserve (Peru) during September 2002. Besides the usual description of the stylet based on whole mounted specimens, we provide a complementary description using SEM, which allowed differentiation of the new species within the currently yet imperfect picture of the Amazonian turbellarian fauna. Although further research is desired, current findings are suggestive of high diversity of free-living Turbellaria in the surveyed region.

An Evaluation Pattern for Antimacrofouling Procedures: Limnoperna fortunei Larvae Study in a Hydroelectric Power Plant in South America

Abstract The effects of global change and globalization of trade on the biosphere spur an increase in bioinvasions and their subsequent impact on ecosystems. Continental invading bivalves are important because of their impact on artificially-constructed structures. Limnoperna fortunei was first found in the Neotropical region in 1991. Since then it has dispersed upstream in the Plata and Guaíba basins at a rate of 240 km y−1. This species causes macrofouling in a manner similar to that caused by Dreissena polymorpha. This paper describes the biology of L. fortunei larvae from a hydroelectric power plant in South America. We suggest the importance of knowing the biology of the invading species and the need to consider the settlement patterns and densities of larvae in each of the sectors of the facility in order to achieve a sustainable prevention/control of macrofouling. This study acquires a global significance under the assumption that L. fortunei will eventually invade North America and Europe.

Allatotropin: An Ancestral Myotropic Neuropeptide Involved in Feeding

Background Cell-cell interactions are a basic principle for the organization of tissues and organs allowing them to perform integrated functions and to organize themselves spatially and temporally. Peptidic molecules secreted by neurons and epithelial cells play fundamental roles in cell-cell interactions, acting as local neuromodulators, neurohormones, as well as endocrine and paracrine messengers. Allatotropin (AT) is a neuropeptide originally described as a regulator of Juvenile Hormone synthesis, which plays multiple neural, endocrine and myoactive roles in insects and other organisms. Methods A combination of immunohistochemistry using AT-antibodies and AT-Qdot nanocrystal conjugates was used to identify immunoreactive nerve cells containing the peptide and epithelial-muscular cells targeted by AT in Hydra plagiodesmica. Physiological assays using AT and AT- antibodies revealed that while AT stimulated the extrusion of the hypostome in a dose-response fashion in starved hydroids, the activity of hypostome in hydroids challenged with food was blocked by treatments with different doses of AT-antibodies. Conclusions AT antibodies immunolabeled nerve cells in the stalk, pedal disc, tentacles and hypostome. AT-Qdot conjugates recognized epithelial-muscular cell in the same tissues, suggesting the existence of anatomical and functional relationships between these two cell populations. Physiological assays indicated that the AT-like peptide is facilitating food ingestion. Significance Immunochemical, physiological and bioinformatics evidence advocates that AT is an ancestral neuropeptide involved in myoregulatory activities associated with meal ingestion and digestion.

New freshwater interstitial Otoplanidae (Platyhelminthes: Proseriata) from the Paraná and Uruguay rivers, South America

This study describes two new freshwater otoplanid species (Platyhelminthes, Proseriata), Itaspiella parana n. sp. and Philosyrtis rauli n. sp., from interstitial habitats of the middle Paraná river (Argentina) and lower Uruguay river (Uruguay), respectively. Kata sp. from the Uruguay river is briefly characterized. This is the first report of otoplanids from freshwater environments of South America. The studied areas are particular biotopes. At present, only a few studies on the turbellarian fauna and its ecology have been carried out in the Paraná river and the records presented here are the first for the Uruguay river. The main difference between other known otoplanid species and Itaspiella parana, Philosyrtis rauli and Kata sp. is their ecological characterization. Until now the family Otoplanidae was known only from marine environments, with a few exceptions.

Expression of a neuropeptide similar to allatotropin in free living turbellaria (platyhelminthes)

Mechanisms coordinating cell-cell interaction have appeared early in evolution. Allatotropin (AT), a neuropeptide isolated based on its ability to stimulate the synthesis of juvenile hormones (JHs) in insects has also been found in other invertebrate phyla. Despite this function, AT has proved to be myotropic. In the present study we analyze its expression in two groups of Turbellaria (Catenulida, Macrostomida), and its probable relationship with muscle tissue. The results show the presence of an AT-like peptide in the free living turbellaria analyzed. The analysis of the expression of the peptide together with phalloidin, suggests a functional relationship between the peptide and muscle tissue, showing that it could be acting as a myoregulator. The finding of immunoreactive fibers associated with sensory organs like ciliated pits in Catenulida and eyes in Macrostomida makes probable that AT could play a role in the physiological mechanisms controlling circadian activities. Furthermore, the existence of AT in several phyla of Protostomata suggests that this peptide could be a synapomorphic feature of this group. Indeed, the presence in organisms that do not undergo metamorphosis, could be signaling that it was first involved in myotropic activities, being the stimulation of the synthesis of JHs a secondary function acquired by the phylum Arthropoda.

A new Paravortex (Platyhelminthes, Dalyellioida) endoparasite of Mesodesma mactroides (Bivalvia, Mesodesmatidae) from Uruguay

Many species of turbellarians (Platyhelminthes) are known to live associated with other organisms, especially invertebrates, as commensals or parasites. The family Graffillidae (Rhabdocoela) includes two genera that parasitize mollusks, Graffílla and Paravortex. Within the latter genus, six species were described as associated with mollusks. In other instances, unnamed Paravortex species were mentioned as parasites of other bivalves and of the body surface of fishes. In the present work, a new Paravortex species that was found in the intestine of Mesodesma mactroides from the Atlantic coast of Uruguay is described. In addition, a bibliographical revision of the known Paravortex species with their respective hosts, location, and distribution is made. Paravortex nicolli, described by Szidat for the Argentinean coast, is mentioned for the first time after the original description, and the authorship and date of description of Paravortex tapetis Noury-Sraïri 1989 are elucidated.

Invasion process of Limnoperna fortunei (Bivalvia: Mytilidae): the case of Uruguay River and emissaries of the Esteros del Iberá Wetland, Argentina

Limnoperna fortunei (Dunker, 1857), during its invasion process in South America, has caused severe impacts both on natural environments altering native biodiversity, ecosystem structure and function-, and on man-made structures causing economic looses. Twenty-one samples were taken from the right bank of the Uruguay River, from tributaries of the Uruguay and Parana Rivers, the drainage of the Esteros del Ibera Wetland. Based on this fieldwork, the presence of larvae and adults of L. fortunei was determined. Also, through the comparison of environmental characteristic with the known tolerance limits for the species, the possibility of its establishment in environments not yet invaded was determined. Most of the sampling stations have features that allow the development of stable populations L. fortunei, including the rivers that drain the Esteros del Ibera, allowing access of this invasive species to this important wetland.

Evaluation of sampling and analysis techniques for early detection of Limnoperna fortunei (Mytilidae) in limit areas of its distribution

on numerous South American rivers includes, among others, alteration of benthonic communities, alteration of fish diet, as well as severe macrofouling problems at industrial water intakes (Darrigran, 2002). Thus, it is fundamental to know the dynamic distribution of this invading species to explain its invading process and to have access to basic informa-tion to predict its distribution/ dispersion pattern.In the framework of a larger Project, in which we try to establish the extreme distribution limits of this species in South America, this work has as its goal to evaluate the efficiency of the sampling techniques of larvae and adults for the early detection of the invading species. For this purpose, sampling was carried out in different water bodies in limit areas of the species distribution in the en-dorreic system in the Province of Cordoba, Argentina.Between December 15 and 18, 2006, quantitative and qualitative samples of benthos and plankton were taken in eight localities looking for adults and larvae of the golden mussel (Table 1). Differing from sam-pling techniques in environments already invaded by the golden mussel where the aim is to know the population distribution of the settlement (e.g. Mansur et al., 2003), the goal of the sampling done in this work was early de-tection of the invading bivalve. The presence of adults of

Composition of meiobenthonic Platyhelminthes from brackish environments of the Galician and Cantabrian coasts of Spain with the description of a new species of Djeziraia (Polycystididae, Kalyptorhynchia)

From 1997 to 1999, the fauna of free‐living Platyhelminthes of the rias ecosystem was studied along the Galician and Cantabrian coast in northern Spain. In total, 72 platyhelminth species are listed in this study. Forty‐two species represent new records for the Iberian Peninsula, three of which represent new genera records. A new species belonging to the genus Djeziraia (Polycystididae, Kalyptorhynchia), Djeziraia longistyla sp. nov., is described in this paper. In this broad‐scale study, a large data set (27 localities) of the estuaries of northern Spain allowed an analysis of the turbellarian species assemblages and the relation of species distributions to salinity, conductivity, oxygen, temperature, and sediment characteristics. Species assemblages (species diversity) of each habitat of the brackish water ecotone are shown. The present study contributes to knowledge on the ability of adaptation of free‐living Platyhelminthes to regimes of brackish water ecotones.