The Corbiculidae Gray, 1847, is a group of limnic clams of considerable ecological and evolutionary potential. Among them, some freshwater species of Corbicula Megerle von Mühlfeld, 1811, are hyper-invasive neozoon in North and South America as well as Europe where currently some taxa are rapidly extending their range rendering them of special ecological importance. Next to the extraordinary invasive potential of the “Asiatic clam”, corbiculids are remarkable in their recently discovered wide spectrum of reproductive strategies, including intrabranchial incubation (brooding). In concert with their colonization ability, these biological properties render corbiculids an ideal model group for studying evolutionary transformations. However, the taxonomy of these clams is in a chaotic state, with phylogenetics being largely unresolved. As a first step towards a comprehensive systematic revision of Corbiculidae, we here document the type material in the Natural History Museum of the Humboldt University in Berlin (ZMB), comprising essentially the invasive Corbicula but supplemented by those taxa traditionally attributed to Batissa Gray, 1853, and other genera. This account adds considerably to the compilation by Counts (1991), who omitted almost all ZMB material of Corbicula. We report on a total of 45 types (33 for Corbicula, 8 for Batissa, 1 for Polymesoda, and 3 of unresolved generic affinity) represented in the ZMB; this reflects more than 7% of nominal taxa known in corbiculids.

In earlier experiments soft, “plasticine” modelling clay was readily consumed by slugs. Therefore, a method for determining the grazing activity of Arion lusitanicus using plasticine baits was tested in the field. Plasticine was exposed on the surface of the soil in small trays shielded from mice by wire mesh screens. After several days of exposure, the quantity of plasticine consumed was determined by weighing. Laboratory experiments showed that the amount of plasticine consumed is proportional to slug body mass, plasticine is eaten over a wide range of temperatures between 6–25°C, and the presence of alternative vegetable food does not decrease consumption. In the field, consumption of such baits was positively correlated with slug numbers and revealed variation in slug grazing activity between sites during the course of a season. The use of plasticine baits is recommended for establishing slug feeding activity in the field. This is probably the best method available to date for quantitative studies. Plasticine was also eaten by several other species of slugs and snails.

Physa hendersoni collected from its type locality near Yemassee, South Carolina, and Physa pomilia from its type locality near Claiborne, Alabama, both display the penial morphology that has been characterized as “type-bc” by Te (1978, 1980). Mate choice tests returned no evidence of premating reproductive isolation between these two populations, and no-choice breeding experiments confirmed outcross fecundity, F1 viability and F1 fertility comparable to incross controls. Significant premating reproductive isolation was documented, however, between the P. hendersoni population and a population of Physa acuta from Charleston, South Carolina, bearing the “type-c” penial morphology. No-choice breeding experiments involving P. acuta and P. hendersoni yielded a mixture of hybrid and selfed progeny, the hybrids apparently sterile. Thus the nomen Physa hendersoni is a junior synonym of P. pomilia, whereas P. pomilia and P. acuta are distinct biological species.

Within the springsnail genus Bythinella, few discontinuous morphological characters allow to unambiguously delineate species-level taxa. Opinions on the alpha-taxonomy of the group are divergent, with some authors recognizing every morphologically distinct local form as a species, while others interpreting such geographical forms as intraspecific variation. Because the value of morphological characters was rarely contrasted with molecular data, such opinions remained untested. In this work, variation between populations was studied through genetics isozymes, phylogeny (DNA), and morphometrics. Eleven populations representing five putative species were sampled from the French Pyrenees, a region where a high number of nominal species are classically recognized. Based on genetic and phylogenetic analyses, the material clusters into three groups, of which one consists of several nominal species. Environmental factors, sexual dimorphism, and genetic factors contribute to the significant morphological variation observed within the genetic groups. Thus, the number of species of Bythinella recognized in the Pyrenees appears probably overestimated, and the characters traditionally used for species delimitation should be re-evaluated.

We present the assessment of the land snail diversity in approximately 50 km² of savanna/forest mosaic in the northern part of Lopé National Park, Gabon, taking into account habitat variation and seasons. A total of 3,745 specimens were collected, yielding 74 species from 12 families, with Subulinidae being the most speciose family. Most specimens were not identified but assigned to Recognizable Taxonomic Units. Extrapolations suggest that the true diversity of the area lies between 79 and 132 species. Overall snail abundance was low, and most species were minute. Spatial and habitat heterogeneity was high, with 33.8% of the species collected from one station only. Rare species made up a considerable proportion of the fauna, with 23.0% of the species represented by one specimen only. The most species-rich habitats were mature forest, Marantaceae forest, rocky forest, and forest fragments isolated in savanna, in that order. Savanna was the least species-rich habitat, and no species were confined to this habitat. Benefits and drawbacks of the Recognizable Taxonomic Units approach are discussed, and suggestions for maximizing mollusc inventories in tropical forests are proposed.

The water permeability rate of the shell wall of Bulinus tropicus (Krauss) was determined with tritiated water to be 1.74 ±1.06 μl water per 24 h. The osmotic pressure of the haemolymph increased three-fold to 300 ± 16 mOsm l⁻¹ after 60 days at 85% r.h. of the air. The [Na] of the snail tissues increased from 38 ± 9.0 mMol l⁻¹ to 68 ± 11.0 mMol l⁻¹ after 60 days at 85% r.h., but at 96% r.h. the increase changed from 40 ± 7.0 mMol l⁻¹ to 55 ± 6.5 mMol l⁻¹. The [K] of the snail tissues increased from 30 ±10.1 mMol l⁻¹ to 58 ± 11.2 mMol l⁻¹ after 60 days at 85% r.h., but at 96% r.h. the increase changed from 30 ± mMol l⁻¹ to 42 ± 10.2 mMol l⁻¹. The oxygen consumption rate (VO₂) decreased by 66% from 60.0 ±19.1μl O₂. g⁻¹ snail. h⁻¹ to 20.5 ± 16.0 μl O₂. g⁻¹ snail. h⁻¹ after 60 days at 96% and 85% r.h. In laboratory experiments without sunlight, snails were still alive after 5 months on mud. In field experiments conducted in direct sunlight on mud, snails were dead within 24 h. At r.h. of 96%, 92%, 85%, 74%, and 57% in the laboratory, the snail survival rate was respectively 40%, 40%, 42%, 22%, and 0% after 60 days. After 60 days at 96% r.h., the snail mass loss was 36%, but only 20% at r.h. of 74%.

Bentharca xenophoricola (Kuroda, 1929) and Bentharca rubrotincta Kuroda & Habe in Habe, 1958, from Japan are re-examined. Based on comparison with the material of Bentharca asperula (Dall, 1881) and Asperarca nodulosa (Müller, 1776), the type species of Bentharca Verrill & Bush, 1898, and Asperarca Sacco, 1898, respectively, as well as on the description, pictures, and photos of Deltaodon tugelae Barnard, 1962, the type species of Deltaodon Barnard, 1962, the following new combinations are suggested: Asperarca xenophoricola (Kuroda, 1930) and Deltaodon rubrotincta (Kuroda & Habe in Habe, 1958). Asperarca xenophoricola has an elongate, inflated, thick shell, with a weakly hirsute periostracum, commarginal lamellate ridges made nodulose by the closely spaced, high radial riblets, and narrow, slightly curved hinge plate, with teeth divided into anterior and posterior sets by a narrow edentulous gap. The anterior set of this species has 7–14 long teeth; the posterior set 6–9 oblique teeth that diverge to a varying degree. This species occurs off Japan, China, and southeastern Australia at depths from 50 to 500 m. Deltaodon rubrotincta has a high, moderately inflated, thick, reddish-brown shell, with white rays and spots, commarginal lamellate ridges and high, nodules, widely spaced radial ribs, a broad, strongly curved hinge plate, with teeth divided into anterior and posterior sets by a shallow, oblique groove. The anterior set of this species forms an oval group of 4–7 long, mostly curved, boomerang-shaped teeth. The posterior set has 9–18 long, oblique teeth that diverge to a varying degree. This species occurs off Japan and China at depths from 100 to 200 m. Expanded descriptions of these species are presented.

Schistosomiasis japonica is one of the most serious parasitic diseases in China. Subspecies of the pomatiopsid snail species Oncomelania hupensis transmit the human blood fluke Schistosoma japonicum, the parasite causing the disease. In at least one study involving the subspecies Oncomelania hupensis robertsoni, there was no clear phylogenetic concordance between the mitochondrial and nuclear data, and it was strongly recommended that future studies incorporate more data from nuclear loci in order to better understand phylogeography and host-parasite coevolution (Wilke et al., 2006). In this paper, we explore genetic diversity based AFLP data involving 25 populations throughout mainland China. AFLP is a DNA fingerprinting technique that detects the polymorphism of the whole genome without prior knowledge of the nucleotide sequence, with the high degree of reproducibility and small amount of template DNA needed.

Our AFLP data show that: (1) the genetic diversity within an O. hupensis population increases gradually with snail sample size, and when the sample size is more than 30 individuals, the genetic variation within one O. hupensis population trends to stabilization. (2) There is high intra-population genetic variation on the mainland of China, and these intra-population genetic variations from different areas differ significantly. (3) The considerable genetic differentiation occurs throughout China. (4) The genetic variation among populations of O. h. hupensis is higher than that of O. h. robertsoni. (5) The patterns of genetic differentiation are basically consistent with geographical distribution of snail populations. Our results are similar to the results of allozymes and COI gene sequences, excluding a snail population from Guangxi Province (Gx-1), indicating that there are three distinct subspecies in mainland China, namely O. h. hupensis, O. h. robertsoni, and O. h. tangi. However, our results do not support that the snail population from Guangxi Province belongs to O. h. hupensis.

We investigated the cold hardiness of a South American freshwater apple snail, Pomacea canaliculata, which began to invade Japanese paddy fields in the early 1980s. Pomacea canaliculata exhibited apparent seasonal fluctuation in its cold hardiness. Snails collected from submerged paddy fields in summer were less tolerant to cold, and none survived exposure to 0°C for five days. With decreasing temperature, together with drainage of its habitat in autumn, P. canaliculata developed cold hardiness, attaining almost 100% survivorship after exposure to 0°C for five days in December. The snails resting in drained fields were approximately nine times more cold tolerant than those collected from submerged fields, based on the time to 50% mortality at 0°C. Snails overwintering in aquatic conditions also acquired cold hardiness.

A systematic revision on the shallow and abyssal species of Scissurellidae and Anatomidae occurring in Sub-Antarctic and Antarctic waters was carried out. This study is based on material from several field trips and museum collections. The shell morphologies of all the species are redescribed and illustrated with scanning electron micrographs. Additional information on the gross anatomy and the radula for seven species is given. A total of six anatomid and seven scissurellid species are recognized as valid in Sub-Antarctic and Antarctic waters, including three new species herein described. Anatomids are represented by the genera Anatoma and Thieleella; the species recognized for the area are: Anatoma conica (d'Orbigny, 1841), characterized by having a globular shell, sculptured with strong axial ribs; Anatoma euglypta (Pelseneer, 1903), has a biconical, delicately cancellate shell; Anatoma shiraseae Numanami & Okutani, 1990, a gradated shell with a distinct spiral ridge on the shoulder and cancellate ornamentation; Thieleella amoena (Thiele, 1912), is globose, strongly sculptured, and with flared lower portion of aperture; Thieleella weddelliana n. sp. is characterized by having a laterally expanded shell, with rounded whorls, deep umbilicus, and strong axial ribs; and Thieleella argentinae n. sp. shows a depressed and widely umbilicated shell, with cancellate sculpture. Scissurellids are represented by the genera Scissurella, Ariella, and Sinezona: Scissurella clathrata Strebel, 1908, is characterized by having an inflated shell with densely cancellate sculpture; Scissurella petermannensis Lamy, 1910, is sculptured with strong axial ribs; Scissurella obliqua Watson, 1886, is nearly smooth and has a shallow umbilicus; Scissurella malvinarum n. sp. also has a smooth shell surface, but the umbilicus is deep and surrounded by 2–6 spiral cords; in Scissurella supraplicata Smith, 1875, the shell is inflated and teleoconch I exhibits strong axial ribs; Ariella subantarctica (Hedley, 1916), has a depressed shell, sculptured with axial ribs and spiral cords, a prominent umbilical callus, and closed foramen; and Sinezona mouchezi (Vélain, 1876), is inflated, sculptured with strong axial ribs, showing a wide umbilicus and a large foramen. The other three scissurellid species previously described from the area – Scissurella eucharista Melvill & Standen, 1912; Scissurella timora Melvill & Standen, 1912; and Scissurella medioplicata Thiele, 1925 – are considered to be synonyms, and