The entire spermatogenesis process and the presence of accessory cells in sperm development in Spondylus princeps Broderip, 1833, and S. calcifer Carpenter, 1857, were described for the first time. Spermatogenesis in both species showed similar anatomical and ultrastructural features. The testis contained amoeboid somatic cells inside the acini, frequently associated with developing gametes. Overall, spermatogenesis followed the typical pattern reported for other bivalve species, except for a few specific details. In S. princeps, intercellular bridges between spermatogonia, as well as one spermatocyte with seven mitochondria were observed. Both species had mature sperm of the ect-aquasperm type, consisting of a head, which contains a spherical-pyriform nucleus and a conical acrosome bounded by two regions of different density, four spherical mitochondria and two centrioles in the middle piece; the flagellum showed a standard 9 2 microtubule arrangement.

Punctum lozeki , new species, is described from damp forests and meadows of southern Siberia, Central Siberian plateau, southern Far East (Russia) and Alaska. The species is characterized by a very narrow deep funnel-shaped umbilicus and tumid whorls that expand rapidly in diameter. It was recorded at 21 sites, and it seems to be a rare species, particularly in Asia, being found at only approximately 5% of all explored and potentially suitable sites. It was limited to wet and mesic taiga, mostly inhabiting brook alluviums, wet calcium-rich woodlands, and treeless sedge marshes. It is only the third Punctum species, along with P. pygmaeum and P. ussuriense, currently recognized in extratropical Eurasia. It also seems to represent another example of a species with a Beringian distribution stretching from Alaska in North America to the Altai Mountains in Central Asia.

We document global phylogenetic pattern in the pupillid land snail genus Vertigo by analyses of nDNA (ITS1 and ITS2) and mtDNA (CytB and 16S) sequence from 424 individuals representing 91 putative specific and subspecific Vertigo taxa. nDNA and mtDNA data were separately subjected to neighbor-joining, minimum evolution, maximum likelihood and Bayesian reconstruction methods, with conclusions being drawn from shared topological structures. Six highly supported, reciprocally monophyletic subgeneric level clades were identified: Vertigo, Alaea, Boreovertigo new subgenus, Isthmia, Staurodon and Vertilla. 88 species or subspecies were also confirmed, nine of which are new and formally described herein: V. beringiana, V. chiricahuensis, V. chytryi, V. genesioides, V. kodamai, V. kurilensis, V. lilljeborgi vinlandica, V. pimuensis and V. pisewensis. Thirteen taxa were synonymized: V. arthuri basidens, V. arthuri hubrichti, V. arthuri paradoxa (= V. arthuri); V. allyniana (= V. modesta); V. andrusiana (= V. columbiana); V. conecuhensis (= V. alabamensis); V. dedecora tamagonari (= V. dedecora); V. elatior, V. idahoensis (= V. ventricosa); V. eogea (= V. ovata); V. modesta insculpta (= V. modesta concinnula), V. modesta microphasma, V. modesta sculptilis (= V. modesta castanea). Qualitative observations of conchological features, ecological preferences and geographic coverage were conducted for each subgenus and genetically supported species or subspecies-level taxon. These demonstrated that: (1) a suite of diagnostic shell features usually exists to demarcate each species-level taxon; (2) shell features were incapable of defining genetically validated subgenera; (3) all subgenera had transcontinental ranges; (4) ⅓ of all species possess continental or trans-continental ranges, with very few having range extents < 1,000 km; (5) all subgenera and fully ⅔ of global Vertigo species and subspecies are found in North America, more than 2.5 times the number found in central and eastern Asia, the second most diverse region. This is similar to several other molluscan groups, such as the polygyrid land snails and unionid bivalves for which North America is the global biodiversity hotspot.

The South American freshwater gastropod Pomacea canaliculata is a highly invasive species. In introduced areas, it is a serious crop pest, responsible for great economic loss and ecological damage. It is also a vector of the nematode Angiostrongylus cantonensis that causes human meningoencephalitis. Many aspects and particularly its reproduction have been extensively studied, but little research has been conducted on this species regarding gene expression. To meaningfully interpret quantitative PCR, a powerful technique to develop this kind of study, validation of reference genes is essential but until now has not been undertaken. We selected the female albumen gland for its major role in egg production in order to evaluate the expression stability of the candidate reference genes EF1-α, RPL7, His H3.3, TUBB, 18S RNA, ACTB and GAPDH. Stability was analyzed under different reproductive activity conditions and defined based on three approaches: geNorm, NormFinder and the comparative ΔCt method. NormFinder selected GAPDH and ACTB as the best option to be used for normalization, whereas geNorm and the comparative ΔCt method indicate RPL7, GAPDH, and 18S RNA as the most stable genes under the conditions studied. These results will facilitate reproductive studies, particularly those using qPCR to evaluate factors that may affect fecundity of this conspicuous invasive species.

Five populations of the invasive species Limnoperna fortunei were studied using polymorphic molecular (nine allozyme loci) and morphological (11 traits) markers in order to understand the patterns of genetic and morphological variability, structure and dispersion dynamics of this species in South America. High levels of genetic variability were found in South American invasive populations, and significant deviations from the Hardy-Weinberg proportions clearly indicated that the invasion process is still under way, probably by means other than natural migration.