Abstract Bioinvasions are one of the main causes of the decline of native biodiversity. Indothais lacera (Born, 1778) is a carnivorous gastropod, native to the Indo-Pacific. We present the first records of I. lacera on the Brazilian coast and the first record of this invasive species in the Western Atlantic. The specimens were found in two locations in the Baía de Todos os Santos, Bahia state, northeast of Brazil. Live specimens were collected in the Itapagipe Peninsula, in Ribeira, Salvador, and dry samples (empty shells) were collected in the extreme north of Itaparica Island. Molecular analyses indicate that there was more than one event of introduction of I. lacera in the bay and alert to the potential impacts that this species can have on the benthic community in the region. We suspect that this exotic species is affecting a native population of Thaisella, which was previously locally abundant but has since become rare.

Abstract An anatomical and taxonomic study of Megalobulimus oblongus (Müller, 1774) and M. conicus (Bequaert, 1948) (Strophocheilidae, Megalobuliminae) is carried out, based mainly on samples from the south-central region of Bahia, Brazil. It revealed interesting anatomical differences in several structures, mainly in the pallial cavity, with greater ramification of vessels in the respiratory region of M. oblongus when compared to M. conicus; and in the genital system of M. conicus, which has a more elongated prostate, and the folds of the penis are more spaced. A taxonomical discussion is presented, including several characters confirmed as typical of the genus and subfamily, such as buccal flange, prerectal valve and pulmonary septum.

Abstract A new species of the recently described genus Habeas is described. The genus is the single urocoptid representant in Brazil. The new species is named as Habeas centroris, occurring in Paz de Salobro, Canarana, Bahia, Brazil. It is mainly characterized by its dense, delicate sculpture, peristome slightly centrally positioned. Its anatomy is similar to what is currently known, differing mainly by small pallial gland, short stomach, presence of anterior duct to digestive gland, vas deferens very posteriorly originated, prostate lying further the vas deferens origin, and visceral ganglia connected directly to pleural ganglia. The new species is another example of how weak the knowledge on the land mollusks in central Brazilian semi-dry region is, a biome that deserves protection.

Abstract Two deep water new species of turriforms are described from south Brazilian coast. One of them is the turrid Polystira tupan sp. nov., one of the largest species of the genus (~80 mm), with proper sculpture, shallow anal notch, collected off Santa Catarina, 350 m. The other is a cochlespirid that has been confused with Cochlespira elegans, a north Atlantic species; as it has different sculpture, shape, peripheric spines, etc., a new species, Cochlespira notomaris sp. nov., is introduced, occurring so far from off Santa Catarina to Rio Grande do Sul, 200-1,000 m. For comparative purposes, the holotype of C. elegans is also illustrated.

ABSTRACT Mirinaba cadeadensis Lange de Morretes, 1952 is restricted to the Paraná state, and found at the municipalities of Morretes, São José dos Pinhais, Paranaguá, Matinhos, and Guaratuba, associated to the Serra do Mar mountains. In this paper, we report the first record of this species in an anthropogenic shell mound. Two shells of M. cadeadensis were located in the internal stratigraphic layers of the Boguaçu shell mound. This is also the first shell mound record for Mirinaba.

Abstract The aim of the study is to describe in detail, for the first time, the internal and external anatomy of Cyrtopleura costata, which displays ellipsoid and elongated valves with beige periostracum, the anterior adductor muscle unites the valves in the pre-umbonal region, with abduction capacity in its dorsal half, sparing the ligament. Two accessory valves are identified: the mesoplax (calcified) located in the umbonal region; and the protoplax (corneus) above the anterior adductor muscle. Internally there is a pair of well-developed apophysis that supports the labial palps and the pedal muscles, and support part of the gills. The posterior half of mantle ventral edge is fused and richly muscular, working as auxiliary adductor muscle. The siphons are completely united with each other, the incurrent being larger than the excurrent. The foot is small (about ⅛ the size of the animal). The kidneys extend laterally on the dorsal surface, solid, presenting a brown/reddish color. The style sac is well developed and entirely detached from the adjacent intestine. The intestine has numerous loops and curves within the visceral mass. The fecal pellets are coin-shaped. The present study certainly may be used as comparative scenario for specimens from other regions of the species range.

Resumo: Amostras de gastrópodes terrestres foram coletadas em sete cavernas na região do município de Presidente Olegário, Minas Gerais, Brasil, durane múltiplas expedições ao longo dos anos de 2012 a 2014. Vinte-e-quatro táxons (mais uma única espécie dulciaquícola) foram encontrados, em sua maioria Stylommatophora. As seguintes espécies são aqui reportadas pela primeira vez para o estado de Minas Gerais: Alcadia iheringi Wagner, 1910 e Helicina sordida King, 1831 (Helicinidae); Cecilioides consobrina (d’Orbigny, 1841) (Ferussaciidae); Entodina gionensis Morretes, 1940 e Scolodonta interrupta (Suter, 1900) (Scolodontidae); Megalobulimus sanctipauli (Ihering & Pilsbry, 1900) (Strophocheilidae); Drymaeus coarctatus (Pfeiffer, 1845) (Bulimulidae); Habroconus semenlini (Moricand, 1846) (Euconulidae); e Solaropsis aff. rosaria (Pfeiffer, 1849) (Solaropsidae). Além disso, as espécies Drymaeus iracema (Simone, 2015) e Drymaeus terreus (Simone, 2015) são aqui sinonimizadas com Drymaeus coarctatus (L. Pfeiffer, 1845).

Abstract: Samples of terrestrial gastropods were collected year-round in seven caves in Presidente Olegário municipality, Minas Gerais state, southeastern Brazil, during several expeditions from 2012 to 2014. Twenty-four taxa (plus a single freshwater species), mainly stylommatophorans, were found in the material. The following species are reported for the first time for Minas Gerais state: Alcadia iheringi Wagner, 1910 and Helicina sordida King, 1831 (Helicinidae); Cecilioides consobrina (d’Orbigny, 1841) (Ferussaciidae); Entodina gionensis Morretes, 1940 and Scolodonta interrupta (Suter, 1900) (Scolodontidae); Megalobulimus sanctipauli (Ihering & Pilsbry, 1900) (Strophocheilidae); Drymaeus coarctatus (Pfeiffer, 1845) (Bulimulidae); Habroconus semenlini (Moricand, 1846) (Euconulidae); and Solaropsis aff. rosaria (Pfeiffer, 1849) (Solaropsidae). Furthermore, the species Drymaeus iracema (Simone, 2015) and Drymaeus terreus (Simone, 2015) are synonymized with Drymaeus coarctatus (L. Pfeiffer, 1845).

Abstract The new genus Stapafurdius gen. nov. is introduced collected from Bahia, Brazil, including two new species: S. glaber sp. nov., the type species, occurs in Ibicoara; and S. costiferus sp. nov., from Andaraí regions. The new genus includes species of about 10 mm, elongated shell, reticulated protoconch, elongated peristome, and wide umbilicus. Both species differ mainly by the sculpture, as S. glaber sp. nov. is smooth, while S. costiferus sp. nov. has strong axial sculpture. http://zoobank.org/C851695E-6BF1-4418-8D8A-8BC7D10CC2FE.

Abstract Despite the great diversity, economic and environmental importance of limnic mollusks, the group is still little investigated in the Brazilian semiarid region, especially in the state of Piauí. Thus, this work aims to gather information on the diversity of limnic mollusks in the Brazilian Northeast and the semiarid region, including new records for the state of Piauí, northeastern Brazil. For this, collections in the urban perimeter of the Itaim and Guaribas Rivers, municipalities of Itainópolis, and Picos, respectively, between October 2017 and September 2019. Besides, a literature review was conducted on studies of malacofauna in the Northeast and the Brazilian semiarid region. A total of 11 species from the classes Gastropoda and Bivalvia were collected on the rivers of Piauí, being the first record of Uncancylus concentricus for the Northeast region. For lotic environments in the state of Piauí, Drepanotrema schubarti, Pomacea canaliculata, Pisidium dorbignyi and Stenophysa marmorata were registered for the first time. Then, it was possible to verify that the Northeast of Brazil has 71 species registered, of which 34 occur in the semiarid. The diversity of species surveyed and the first record of the occurrence of several of them for the semiarid region demonstrate the importance of expanding studies involving this group to other areas. The present study is the first to gather and increase the information available on the fauna of limnic mollusks for the Northeast and Brazilian semiarid regions. The information gathered here may contribute to future research and to the species conservation and the environments they occupy, especially considering the presence of non- native and vector species.

Abstract The prey of a recent described characid fish, so far endemic of the small lake Pratinha (Iraquara, Bahia, Brazil), a small (~2.5 mm) lentic gastropod, revealed to be a new (possible endemic) species. It is herein formally described as Heleobia brucutu sp. nov. The description includes anatomical features, revealing interesting idiosyncrasies such as egg laying attached to shell, and penis lacking glands, but with terminal papilla. The new species appears to be endemic of that small lake as much as its fish predator. As the species is now formally described and named, protective efforts must be implemented.

Abstract Several deep-water mollusks collected during the Marion Dufresne MD55 expedition off SE Brazil have been studied in recent papers. The present work focuses on eight species belonging to the cerithioidean families Cerithiidae, Litiopidae, Modulidae and Planaxidae. Three species have their geographic distributions greatly expanded: Bayericerithium bayeri Petuch, 2001 from Pernambuco to Rio Grande do Norte and Ceará states (north) and to Bahia and Espírito Santo states (south), Brazilian coast; Ittibittium oryza (Mörch, 1876), from the Caribbean to the SW Atlantic; and Angiola lineata (Costa, 1778), from Trindade Island, Brazil to the Abrolhos Slope, nearly 870 km westward. Four species reported herein had their bathymetric ranges greatly expanded: Alaba incerta (d’Orbigny, 1841) from 0-40 m to 300 m; B. bayeri from 0-2 m to 120 m (live specimens); Litiopa melanostoma Rang, 1829 from 0-805 m to 1,550 m; Fossarus orbignyi Fischer, 1864 from 0-40 to 830 m (shells only).

Abstract The new bulimulid species, Drymaeus currais sp. nov., is described based on shell and anatomical features. It is endemic of Guapirá Island, belonging to the Currais Archipelago, a small protected area off Paraná coast. The species is thus, based at least on endemicity, endangered. It has as closest species D. castilhensis, another endemic species of Castilho Island, ~70 km northwards. Its main exclusivities are a banded shell (except for periumbilical area); a ureter ~1/3 opened (furrow); an external anus; a slightly different buccal and intestinal arrangement; a penis lacking internal chambers; a small receptacle with a genital appendix. Zoobank Register: urn:lsid:zoobank.org:pub:25B25A8B-CED0-4284-A799-5383998BE481.

Abstract The genus Mytilus comprises a large number of bivalve mollusk species distributed throughout the world and many of these species are considered invasive. In South America, many introductions of species of this genus have already taken place, including reports of hybridization between them. Now, the occurrence of the Mediterranean mussel Mytilus galloprovincialis is reported for the first time from the Brazilian coast. Several specimens of this mytilid were found in a shellfish growing areas in Florianópolis and Palhoça, Santa Catarina State, Brazil. Morphological analysis of the shells and molecular analysis through sequencing of the cytochrome oxidase subunit 1 (COI) confirmed the taxonomic identification. The species is known for its great invasive potential and can become a major environmental problem for seafood business and coastal communities, as it can compete and even hybridize with local species.

Abstract The distinction of squid species in the genus Doryteuthis is not easy due to their morphological similarity, lack of conspicuous specific characters, and overlap geographical occurrence. This difficulty has leading to an almost exclusive molecular approach, and a premature neglect of the morpho-anatomy. To emphasize that the squid phenotypic features can be useful to identify, as well as to perform any comparative analyses (such as taxonomy and phylogeny), two close species were selected as outset. Doryteuthis pleii and D. sanpaulensis are common sympatric squids in Brazilian waters, commonly used in fisheries, not so difficult to distinguish by external features of the adult specimens. The samples were analyzed from biometric data to dissections, and the found most expressive characters to distinguish them are the mantle-fin ratio; morphology of the tentacle club, its ratio compared to the mantle length; hectocotylus morphology and nidamental gland morphology.

Abstract Exotic species are those that occur in an area beyond their natural limit and they are considered invasive when they cause harm to the economy, environment, or human health. In coastal environments, ballast water and inlays on the hull and other parts of vessels are the main ways of introducing invasive aquatic alien species. Nassarius foveolatus (Dunker, 1847) is native from the Central and East Indian Ocean to the East China Sea. The first specimens (empty shells) of N. foveolatus were collected manually on November 11, 2017 on the Rocio footbridge, located in the Paranaguá Estuarine Complex, on the coast of the State of Paraná, southern Brazil. Posteriorly, live specimens were collected in other localities of this bay. It is already possible to infer that the specimens of N. foveolatus occur together with the native specimens of N. vibex (Say, 1822), having the same niche. As previously only N. vibex existed in that place, at least a displacement of this native species has been occurred. However, certainly future ecological studies may confirm this displacement and additional consequences to the local ecosystem, as nassariids can be predators and scavengers. Control procedures should be also greatly implemented.