We evaluated the radula shape of Littoraria angulifera from mangroves and rocky shores on the Brazilian coast. We compared snails sampled in a mangrove and on a rocky shore located about 100 m apart, and also from locations hundreds of km apart. Smaller individuals sampled on rocky shores have elongated cusps, whereas larger individuals have subequal cusps, similar to those observed in mangrove specimens. Distinct factors in each environment might exert different effects on the radula shape of L. angulifera. The greater morphological diversity observed on the rocky shores might be due to the heterogeneity of algae composition and partitioning of resources, a hypothesis that can be tested in further studies.

Lowland river degradation of agricultural areas is a problem not only in Poland but also in Europe and worldwide. The objectives of the present study were to determine the biodiversity of the gastropod communities in lowland rivers under the impact of agriculture, the relationship between gastropod communities and environmental factors, and to estimate the usefulness of the gastropod communities as an indicator of water quality. Four rivers that flow through an agricultural area were investigated. A high value of chlorophyll a, a low value of total dissolved oxygen and a high concentration of phosphates or total phosphorus and organic matters are present in the rivers. Gastropod communities in the rivers of the Ciechanowska Upland are influenced by bottom sediments, the physical and chemical parameters of water, and the abundance of macrophytes, which are typical of eutrophic water. In the rivers of the Ciechanowska Upland, gastropods can be biological indicators of dissolved oxygen in water – Viviparus viviparus (Linnaeus, 1758) and Lymnaea peregra (O. F. Müller, 1774) can be indicators of anthropopressure. The values of diversity indices varied from site to site, but did not decrease along the river.

Samples of fossil land snails were made at 14 sites on the island of Porto Santo, Madeiran archipelago. Material in stratigraphical sequences could be dated by A/I racemization calibrated against radiocarbon dating, and against Uranium/Thorium estimates based on Madeiran material. Although errors associated with the oldest samples are large, it is clear that the oldest shell-bearing deposits are at least 300 ka old, and probably much older. Some taxonomic difficulties have been resolved by morphometric studies. The geographical pattern in the fossils (in both faunal composition and morphometrics) resembles closely that seen today, the southwest of the island being particularly distinctive. Of 58 native taxa found in the deposits, 22 are extinct on the island, though four still survive on Madeira. Extinction has been greater in the southwest than elsewhere, and early fossil faunas there are richer than later ones. As on Madeira, more than half of this extinction seems likely to be the consequence of human disturbance, which has also reduced and fragmented the ranges of other species. The overall pattern is of distributional stasis in many species, reduction of range or extinction in many others, but very few cases of range expansion. Neither extinctions nor changes in apparent abundance can be related to known changes in global climate over the period involved. This relative stasis is in marked contrast to the situation on Madeira, only 40 km away, where there are temporal shifts in the fauna, and evidence of colonization events. Possible reasons for this difference are discussed.

Distribution and morphology of putative nitroxidergic (NO-ergic) cells were studied in the labial palps, esophagus, stomach, digestive gland, and intestine of the bivalves Crenomytilus grayanus, Modiolus modiolus, and Mytilus coruscus using NADPH-histochemistry (Hope & Vincent, 1989). NO-producing elements were found in all examined organs and regions of the digestive system. NADPH-diaphorase-(d)-positive staining was readily detectable in neurons, secretory cells, brush border epithelial cells, and in the nervous plexuses. Intraepithelial nerve cells were the most common NADPH-d-positive cell type throughout the digestive tube. These cells had a fusiform perikaryon, which gave rise to a thin apical process that extended toward the gut lumen, whereas the basal process contacted the basiepithelial NADPH-d-positive plexus. In the major typhlosole of C. grayanus, these cells constituted up to 1.28% of the total number of epithelial cells. The bivalve species studied exhibit a similar distribution pattern of NADPH-d-positive cells, which lie separately or form small groups of two to three in the basal part of the epithelium, being most abundant in the dorsal and ventral regions. Subepithelial NADPH-d-positive neurons were found in C. grayanus and M. modiolus. The labial palps, lips, and esophagus contained an abundance of intraepithelial and subepithelial secretory cells that stained positive for NADPH-diaphorase. Moreover, NADPH-diaphorase was detected in brush border epithelial cells of the primary and secondary ducts of the digestive gland. All examined regions of the digestive system contained basiepithelial and subepithelial NADPH-d-positive nerve fibers that formed loose to highly developed plexuses. The most prominent plexuses were found in the lips, esophagus, and intestine of the species studied.

A U.S. National Institutes of Health-sponsored study was initiated in 1998, ending in 2002, to examine the hypothesis that bovines, buffaloes in particular, were responsible for the persistence of schistosomiasis in human populations living in and around Poyang Lake, Jiangxi Province, P. R. China. The two villages are the focus of this paper, the experimental Jishan Village and the control Hexi Village. The prevalence and intensity of infection of humans and buffaloes were determined. Then, all inhabitants of all the villages were treated with praziquantel, while only the buffaloes of the experimental (intervention) village were treated. Following treatment, rates of reinfection of people in the two villages and buffaloes in the experimental village, as well as the ongoing prevalence of infections in the buffaloes of the control village were monitored annually.

Quantitative collections of snails were made pre- and post-flood for a total of nine seasons to determine the density of snails, density of infected snails, and prevalence of infected snails. Collections were made from ecologically different village zones and from hot spots for persistent snail infections within zones. The hypothesis was that treatments in the experimental village would drive down snail infections to 80% or more below pre-trial levels. This paper makes the case that the intervention did not achieve reducing snail infections village-wide by even 50% or more. The probable reasons for this failure are discussed.

The significant findings of this longitudinal study are several: (1) Foremost, the intervention did not achieve the goal of significantly reducing snail infections in Jishan. (2) To understand the dynamics of Schistosoma japonicum transmission throughout large areas, such as the administrative villages of Hexi and Jishan, it is important to partition the area into clearly definable ecological zones. (3) We have found that the greatest risk of infection is in very small areas within zones that we call hot spots. (4) The most important indicator for risk of infection is the density of infected snails, not the prevalence. (5) There are very significantly more infected snails per area in hot spots than in non-hot spots. (6) Density of infected snails is not correlated with density of snails overall. (7) The sampling strategy of zones, squares, and random selection of 20 4 m² cells within squares has enabled robust statistical analyses of snail populations that have a strong negative binomial distribution. Sampling twice a year (before the floods and after the floods) for at least 8 or 9 seasons has provided a time series enabling a robust assessment of trends in the experimental and control villages. Paying close attention to environmental factors as they impact results is critical.

A three-year study was conducted to determine oviposition periods of the volutid gastropod Adelomelon brasiliana, the abundance and distribution pattern of its egg capsules in the region of Mar del Plata, Argentina. Results indicate that oviposition was correlated with water temperature. Reproduction occurred from September/October to May/June. Because egg capsules are not attached to the substratum and drift freely on the bottom along a narrow zone close to the shoreline, they can become stranded on the beach after storms, thus suffering mass mortality. This was reflected by a decline in snail recruitment during one study year in which storm surges were frequent and severe. The developmental stages of the egg capsules were characterized, and the proportion of early and late developmental stages determined monthly. This allowed an estimate of recruitment during each reproductive season. Twenty percent of the egg capsules at hatching contained one to three embryos that were considerably smaller than their siblings and 6% of the egg capsules at the same developed stage had one to four teratological embryos. Egg capsules laid down on the sea bottom showed an aggregated distribution pattern. The average developmental time was 57 ± 4 days. Protein and sugar concentration and pH of the intracapsular fluid decreased as embryo development progressed. Several proteins with different molecular weights were present in the intracapsular fluid during the entire intracapsular development.

As a first step towards a comprehensive revision of the South American genus Epiphragmophora Doering, 1874, taxa described from Argentina and Bolivia, inhabitants of the rainforest Yungas (Amazonian biogeographic subregion) Monte, Pre-Puna biogeographic provinces, and Chacoan biogeographic subregion are studied. Special attention has been paid to the morphology of the terminal genitalia with respect to its relevance for systematics. The revision is based on the examination of nearly all type material, plus extensive field work and examination of additional material deposited in several museums. Shell, pallial system and genitalia of each species have been described and illustrated, some of them for the first time. Detailed description on the structure and connections of the dart sac apparatus and associated mucous glands in the terminal genitalia in each species is provided. A total of 27 species, including three new taxa, are described from the region. From the total number of species, the anatomy of seven species is described for the first time. Six unambiguous synapomorphies support the monophyly of the genus: body whorl surface malleated with diagonal ribs (character 1 [2]), umbilicus overlapping but not fused to body whorl (character 2 [1]), peristome thick, widely reflexed (character 4[1]), mucous glands unequal in size and shape (character 15 [1]), insertion of mucous glands ducts in middle portion of dart sac (character 17 [1]), and penial retractor muscle inserting in medial epiphallus (character 23 [1]). Most of the synapomorphies of the generated phylogenetic hypothesis are characters from the genitalia, and shell characters proved to be less informative. The short duct of the bursa copulatrix, a character that traditionally had been used to define the genus is characteristic only of a small group of species. The distribution of the Argentinean species studied is illustrated on maps according to the biogeographic areas. An area cladogram based on the cladistic analysis is presented. According to this hypothesis, the species inhabitants of the Yungas biogeographic province are basal groups of the remaining species inhabitants of the Chacoan, Monte, and Pre-Puna regions. The Monte and Pre-Puna species conform a monophyletic clade. The biogeographic relationships are in agreement to former studies on Latin-American entomofauna (Morrone, 2006).

Few studies have dealt with the geographic distribution of freshwater snails in Argentina. The objectives of this study were to: (1) determine species and family richness and diversity patterns; (2) verify if species richness behaves according to Rapoport's rule; (3) identify and classify species according to their distributions; and (4) identify endangered species. A grid was applied to a map of Argentina, with each of 340 squares (SUs) representing 10,000 km². A database of 3,376 records was analyzed. Of the 101 species belonging to ten families recorded in Argentina, four are introduced and 40 are endemic to Argentina. The Lithoglyphidae have the highest number of species (22). The highest species richness/SU was recorded in the Brazilic subregion at Salto Grande (32 species) on Uruguay River, and parts of the Río de la Plata (31). In this subregion the species richness values increase from west to east. The highest richness in the Chilean-Patagonian subregion was detected at San Carlos de Bariloche, Río Negro province (9), and the Chilinidae contained the largest number of species. In Argentina, the north-south decline species pattern could be explained through Rapoport's rule. In Patagonia, the species richness gradients do not show significant west-east trends. Most of the native species of freshwater molluscs of restricted distribution can be considered endangered (about 45 species) but need further study.

Two new Hirtudiscus species are described from Colombia. Hirtudiscus triserialis n. sp. from the Departamento Cundinamarca is characterized by a large shell with three rows of up to 1 mm long hairs at the periphery and a distinctly sunken spire. Hirtudiscus antiochiensis n. sp. from the Departamento Antiochia is characterized by a moderately large shell with moderately dense growth striae and hairs up to 0.5 mm long.