In 1957 Bequaert summarized the knowledge of the non-marine mollusks of Chiapas. Thompson made several additions in various papers between 1966 and 1976 and in them described species new to science. Later, Naranjo-García et al. (2000) and Naranjo-García (2003) described two more new species. In 1993 Naranjo-García noticed that the land mollusks of Chiapas differed from the other Pacific states of Mexico and had a closer relationship with the land mollusks of Guatemala. Samples from various Chiapas sites in the National Collection of Mollusks (Colección Nacional de Moluscos) as well as material from the California Academy of Sciences were studied in order to prepare this work. The total diversity for the state of Chiapas stands at 128 species in 22 families, about 10.9% of the known fauna of the whole of Mexico. Fifty-five species have been recorded from a single locality (43% of the fauna of the state). Their present status is unknown: whether they are endemic or not, whether they are still extant or threatened, or extinct. These are issues to be resolved. Best recognized species are Lysinoe ghiesbreghti (Nyst, 1841) (which is distributed in Chiapas and Guatemala); Helicina tenuis Pfeiffer, 1849 apparently from Jalisco to Guanajuato states to southeastern México. Orthalicus princeps (Broderip in Sowerby, 1833) is widely distributed along the Gulf of Mexico, Guatemala, Belize, Honduras, El Salvador, and Costa Rica. Among the micromollusks, Lucidella lirata (Pfeiffer, 1847) is the most frequently found snail at the Montes Azules Biosphere Reserve (Southeast Selva Lacandona). Leptinaria lamellata lamellata (Potiez and Michaud, 1838) Cecilioides sp. Férussac, 1814, and Oxyloma sp. Westerlund, 1885 are new records from the same area. Recent changes in the use of the land may modify our view of the terrestrial mollusks of Chiapas state.

The population structure of three endemic land snail species of the genus Discula (Lowe,1831) on the archipelago of Madeira were studied. Ten allozyme loci were screened in 13 populations (11 from Madeira Island and two from the adjacent Desertas Islands) of D. polymorpha (Lowe, 1831), two populations of D. attrita (Lowe, 1831) and one population of D. calcigena (Lowe, 1831) from Porto Santo Island. All populations, except those from the Desertas, showed high levels of genetic variability. Deviation from Hardy- Weinberg equilibrium due to heterozygote deficiency was detected in all D. polymorpha populations from Madeira and populations of D. attrita. This deficiency was mainly attributed to inbreeding within the populations. No heterozygote deficiency was found in D. calcigena, probably due to the larger population size of this species in the recent past. The F_ST values were significant in many pairwise comparisons between the populations of D. polymorpha, with the highest values occurring between populations from Deserta Grande and the peninsula of Madeira. All interspecific F_ST values were highly significant. F_ST values between populations of D. polymorpha from Deserta Grande and the Madeiran peninsula were comparable to observed interspecific values. Based on the factorial analysis all Madeiran populations grouped together, the populations from Deserta Grande formed a separate group, while the two populations of D. attrita show clear structuring.

Several morphological and molecular studies support the north African origin of the brown snail Cornu aspersum aspersum (Müller, 1774) and evidence suggests the presence of two morphologically and genetically different haplogroups in this area. However, all investigations were confined mainly to the western Mediterranean region, whereas the genetic structure and geographical distribution of eastern Mediterranean populations remained largely unknown. The present study attempted to elucidate the fine-scale phylogeography of C. a. aspersum along the Croatian coast and islands. Both Bayesian phylogenetic inference and network-based approaches showed a strong genetic splitting of Croatian 16S rRNA, COI and cyt b sequences into two well-defined groups consistent with previous eastern and western lineages. The eastern haplotypes were more frequent and distributed over a wider geographic area than western haplotypes. The genetic admixture of eastern and western gene pools observed in three Croatian populations would signify a new secondary contact zone in Croatia between both previously defined lineages. Our results suggest that: 1) the eastern lineage, which disappeared in most Mediterranean regions, persisted in the Adriatic area probably through several climatic cycles accumulating genetic differences and 2) two or, more likely, several independent post-glaciation colonization routes crossed at this contact zone, bringing two distinct C. a. aspersum haplogroups together.

The Bostryx stelzneri species complex is taxonomically reviewed with the description of a new species. This complex is formed by Bostryx stelzneri (Dohrn, 1875), B. peristomatus (Doering, 1879), B. scaber (Parodiz, 1948) and Bostryx roselleus n. sp., all distributed in Argentina. Bostryx peristomatus and B. scaber are elevated to specific status on the basis of morphological characters. This complex has the spire less than half the total shell height and the aperture higher in relation to total shell height than in any other species of the genus. Traditional shell morphometry and a geometric morphometric analysis were used to document shell variation in size and shape among species. Radula, jaw and shell morphology were examined with SEM. All species in the complex are described or redescribed using new morphological information. In this species complex, pallial organs are very similar among species and vary only in the degree of opening of the secondary ureter. The genitalia differ in the relative proportion of organs, such as length of vagina relative to free oviduct and penis or epiphallus length relative to penis length. Sculpture of the inner wall of the flagellum and epiphallus is similar in all species studied, whereas sculpture of the inner wall of the penis is variable. Geometric morphometric analysis allows an objective interpretation of shell shape variation detecting differences in shape components irrespective of the differences in size between Bostryx Troschel, 1847 species of the stelzneri group.

We used artificial substrates to investigate the seasonal variation in colonization patterns of subtidal prosobranch gastropods in Gran Canaria (Canary Island, Spain, north-eastern Atlantic), via monthly deployment of artificial substrates throughout an entire annual cycle from February 2009 to January 2010, on each of four habitat patches (seagrasses, sandy patches, ‘urchin-grazed’ barrens and macroalgaldominated beds) within a coastal landscape. A total of 8,524 prosobranch gastropods, including 12 dominant taxa, were collected as postlarval, juvenile, and adult individuals. In general the amount of variability explained by the type of habitat slightly dominated over seasonal variation, which was outweighed by variation from month to month, to explain colonization patterns. Throughout the study, larger numbers of colonizers of Bittium spp. (Leach in Gray, 1847), Columbella adansoni (Menke, 1853), Gibberula caelata (Monterosato, 1877), Mitra spp. (Lamarck, 1798), Rissoa spp. (Freminville in Desmarest, 1814), and Smaragdia viridis (Linnaeus, 1758) were observed in artificial substrates deployed in vegetated substrates, highlighting the relevance of vegetation as a matrix habitat for subtidal prosobranch gastropods. Cerithium rupestre (Risso, 1986) and Clavatula mystica (Reeve, 1843), however, were mainly observed on sandy patches. Rissoa spp. showed a peak in the arrival of new colonizers during spring-early summer whereas Tricolia pullus canarica (Nordsieck, 1973) showed a peak during winterearly spring. Importantly, the other prosobranch gastropods did not show significant differences in the arrival of colonizers between annual seasons. In summary, these results demonstrate that seasonality is strongly outweighed by small-scale temporal variability (here variation from month to month) and the type of habitat patch as drivers of prosobranch gastropod colonization patterns in coastal landscapes.

The genus Rissoella Gray, 1847 in the Bahamas is revised based on specimens captured on regular field trips undertaken in Abaco since 1982. New data are given on Rissoella galba Robertson, 1961, and four new species bearing preumbilical cords are described. Rissoella caribaea Rehder, 1943 is regarded to be endemic to Florida. A key to the species of Rissoella in the Bahamas is provided. The new species, Rissoella abacoensis sp. n., Rissoella edbayeri sp. n., Rissoella sanguinea sp. nov., and Rissoella kennethi sp. n., are described based on their habitat, external anatomy, and internal anatomy studies, of which detailed schemes are provided. Additionally, a discussion on the influence of the morphology of the seabed, the type of development and the size of the individuals, conditioning speciation in Rissoella is tackled in order to explain the tendency to endemism of the group.

Cyamiocardium domaneschii n. sp. is described from shallow waters off the Southeastern coast of Brazil. An anatomical study provides comparisons with other Cyamioidea. It has a small shell (up to 3.1 mm in length), valves with a rounded contour, external radial sculpture, a distinct large prodissoconch, and hinge structure characteristics of the genus Cyamiocardium Soot-Ryen, 1951. Three well-defined pallial openings are present; tentacles border the anteriormost part of the pedal opening and the inhalant and exhalant apertures. The inner demibranchs are larger than the outers, do not have interlamellar junctions, and form a spacious brooding chamber. It is dioecious and developing oocytes are covered by a thin follicular tissue, which persists as a covering of each brooded young. Offspring are retained up to the juvenile stage, and are attached to the gill filaments by a long stalk. The foot has a narrow, grooved ventral sole; no byssus threads were observed. An active burrowing or crawling behavior is suggested for C. domaneschii n. sp., as there are well developed statocysts. This finding of a cyamiid from Brazil represents the extension of the geographical distribution of this family further north in the southwestern Atlantic Ocean. This study also reveals that some anatomical characters are variable in the genus Cyamiocardium: in C. denticulatum (Smith, 1907), there are only two pallial openings and its foot does not have a ventral sole. The attachment of young to the gills are not related to nourishment, and here for C. domaneschii n. sp. it is suggested that the stalk is only used as a “safety belt”, preventing embryos and juveniles to be released before the end of their development. More studies remain to be done on the anatomy of cyamioideans, particularly on living specimens; we paid attention to common characters used for discussions on the taxonomy and biology of these bivalves.

Octopus hubbsorum Berry 1953 occurs in a wide region of the tropical eastern Pacific. It is the principal target species in the octopus fisheries, but no information is available with regard to embryonic and larval development. The objective of this study was to describe O. hubbsorum eggs, embryos, and paralarvae under laboratory conditions. One O. hubbsorum female with egg clutch was collected (15°39′N, 96°31′W) on 26 October 2012. Embryonic development lasted from 20 to 30 days. The newly hatched paralarvae are planktonic; morphologically, this feature is expressed by a relatively small arm-length, 3 suckers per arm, and mean mantle length of 1.27 ± 0.14 mm. This article provides a detailed survey of O. hubbsorum, embryogenesis from organogenesis through hatching under laboratory conditions; including detailed descriptions of externally visible morphological features that are easily distinguished in either live or freshly fixed organisms under a dissecting microscope.