Variation in hypodermic radular teeth of the snail auger Hastula cinerea (Born, 1778) (Gastropoda:Terebridae).

Gastropods of the superfamily Conoidea are present in high diversity in the oceans and are characterized by having modified foregut anatomy and radular morphology. This study provides details on variations in the radula teeth of the species Hastula cinerea, which have hypodermic radula teeth of the toxoglossan type and are part of the Terebridae family - inserted in the Conoidea superfamily. Hastula cinerea specimens were collected at Flecheiras beach, Trairi, Ceará, Brazil. Scanning Electron Microscopy (SEM) was performed to analyse the radula specificities. Thirty specimens were used between females and males, with different sizes. The total length of the shell and the length of the teeth of all analysed specimens were measured. With the SEM result, more than one radula tooth morphotype was found for the species H. cinerea. The pattern of the teeth found is similar to the hypodermic teeth of the group, however, with structural and length differences between smaller and larger individuals. It was possible to observe three radula variations (morphotype-1, morphotype-2 and morphotype-3), 26 related to different sizes of individuals, regardless of sex, configuring a variation in the radula teeth. Therefore, this result brings a contribution that stimulates future research with the functional morphology of H. cinerea and others auger snails.

Interconnected marine habitats form a single continental-scale reef system in South America.

Large gaps in reef distribution may hinder the dispersal of marine organisms, interrupting processes vital to the maintenance of biodiversity. Here we show the presence and location of extensive reef habitats on the continental shelf between the Amazon Reef System (ARS) and the Eastern Brazilian Reef System (ERS), two reef complexes off eastern South America. Formations located 20-50 m deep include both biogenic and geogenic structures. The presence of diverse reef assemblages suggests the widespread occurrence of rocky substrates below 50 m. These habitats represent an expansion of both the ARS and ERS and the closure of the only remaining large-scale gap (~ 1000 km) among West Atlantic reef environments. This indicates that the SW Atlantic harbors a single, yet heterogeneous, reef system that stretches for about 4000 km, and thus, represents one of the largest semi-continuous tropical marine ecosystems in the world.

Predator control of marine communities increases with temperature across 115 degrees of latitude.

Early naturalists suggested that predation intensity increases toward the tropics, affecting fundamental ecological and evolutionary processes by latitude, but empirical support is still limited. Several studies have measured consumption rates across latitude at large scales, with variable results. Moreover, how predation affects prey community composition at such geographic scales remains unknown. Using standardized experiments that spanned 115° of latitude, at 36 nearshore sites along both coasts of the Americas, we found that marine predators have both higher consumption rates and consistently stronger impacts on biomass and species composition of marine invertebrate communities in warmer tropical waters, likely owing to fish predators. Our results provide robust support for a temperature-dependent gradient in interaction strength and have potential implications for how marine ecosystems will respond to ocean warming.

Alien hotspot: Benthic marine species introduced in the Brazilian semiarid coast.

In this study, we provide a baseline assessment of introduced marine species along the extensive (~600 km) Brazilian semiarid coast. We reported 27 introduced and 26 cryptogenic species. Moreover, the main vectors of introduction were ballast water, shipping lines, oil and gas activities, biofouling, and rafting on plastic debris. The taxa were Ascidiacea (17 species) and Bryozoa (17), followed by Crustacea (6), Mollusca (6), Cnidaria (3), Echinodermata (3), and Porifera (1). Among these invertebrates, some species are recognized as drivers of impacts such as the invasive corals (Tubastraea tagusensis and Tubastraea coccinea), the bivalves Isognomom bicolor and Perna viridis, the crab Charybdis hellerii, the brittle star Ophiothela mirabilis, and, finally, the bryozoan Membraniporopsis tubigera. These species threaten the biodiversity of unique ecosystems such as intertidal sandstone reefs, shallow-water coral reefs, and mesophotic ecosystems. Moreover, the up-to-date results highlight that this region is a hotspot of bioinvasion in the tropical South Atlantic.

Structure, growth and CaCO3 production in a shallow rhodolith bed from a highly energetic siliciclastic-carbonate coast in the equatorial SW Atlantic Ocean.

Rhodolith growth and CaCO3 production remain poorly quantified along the SW Atlantic Ocean, and it is difficult to relate the available measurements with biomass estimates. Suboptimal conditions may clarify how harsh environments influence nodule growth and abundance, elucidating their relationship. Off the energetic South American equatorial coast a rhodolith bed (~65 km2), formed mainly by Mesophyllum sp. and Lithophyllum sp., alters the regional sedimentary pattern and sustains a diverse biota. Its nodules present fast growth rates (2.8 mm year-1), but small biomasses (18 nodules∙m-2 covering 26 ± 3% of the substrate), resulting in a CaCO3 production of 163.33 g m-2∙year-1. Despite the small biomass, the bed seems stable, with living and dead nodules both on and inside the substrate. And the suboptimal environment apparently affects growth and abundance independently. Therefore, fast growth rates and relevant structural roles are not necessarily associated with dense rhodolith assemblages, and ecological assessments of rhodolith beds should consider the dynamics of both individual nodules and the whole population.

Molecular evidences confirm the taxonomic separation of two sympatric congeneric species (Mollusca, Gastropoda, Neritidae, Neritina).

A reliable taxonomy, together with more accurate knowledge of the geographical distribution of species, is a fundamental element for the study of biodiversity. Multiple studies on the gastropod family Neritidae record three species of the genus Neritina in the Brazilian Province: Neritina zebra (Bruguière, 1792), Neritina virginea (Linnaeus, 1758), and Neritina meleagris Lamarck, 1822. While N. zebra has a well-established taxonomic status and geographical distribution, the same cannot be said regarding its congeners. A widely cited reference for the group in Brazil considers N. meleagris a junior synonym of N. virginea. Using a molecular approach (phylogenetic, species delimitation, and statistical parsimony network analyses), based on two mitochondrial markers (COI and 16S), this study investigated if N. virginea and N. meleagris are distinct species. The molecular results confirmed the existence of two strongly supported distinct taxonomic entities in the Brazilian Province, which is consistent with the morphological descriptions previously proposed for N. virginea and N. meleagris. These species occur in sympatry in the intertidal sandstone formations of Northeastern Brazil. Despite the great variation in the colour patterns of the shells, the present study reinforced previous observations that allowed the differentiation of these two species based on these patterns. It also emphasized the importance of the separation of these two clades in future studies, especially those conducted in the Brazilian Province, since these species may cohabit.

A new species of Petalobrissus Lambert 1916 (Echinoidea: Faujasiidae) from the Jandaíra Formation, Potiguar Basin (Brazil).

A new Late Cretaceous species of Petalobrissus, Petalobrissus lehugueurae sp. nov., is described from the Jandaíra Formation, Potiguar Basin, state of Rio Grande do Norte. To date, this genus comprises a total of 20 species, only two of which, Petalobrissus setifensis and Petalobrissus cubensis have so far been recorded from the Jandaíra Formation. Petalobrissus lehugeurae sp. nov. is distinguished from its congeners in that gonopores occupy only a small portion of the genital plates, in having a slit-like periproct and a unique abrupt depression of the test that forms a pronounced keel below the periproct. In addition, an identification key to species of Petalobrissus is presented.

Marine benthic communities affected by the Doce River (southwestern Atlantic): Baseline before a mining disaster.

Prior to Brazil's worst environmental disaster, caused by a mining dam collapse, we had carried out a study of the marine benthic macrofauna (11-51 m depth) under the influence of the Doce River. Our results showed significant diversity, in which mollusks, polychaetes, and crustaceans had the highest frequency, density, and abundance, represented by 162 families in summer and 173 in winter. Our results suggested that richness, abundance, and diversity increase with distance from the coast. Furthermore, with increasing distance from the coast and river mouth, in addition to increasing depth, there was a differentiation in composition and abundance. Multivariate analyses showed depth, carbonate, and organic matter as important factors that explain variations in composition and diversity across the continental shelf. The results could provide an invaluable baseline for measuring the effects on shallow and mesophotic communities of one of the largest tailings dam failures worldwide.

Isolation of Chamigrene Sesquiterpenes and Absolute Configuration of Isoobtusadiene from the Brittle Star Ophionereis reticulata.

The chemical study of the Brazilian brittle star Ophionereis reticulata led to the isolation of three chamigrene sesquiterpenes, including the partially characterized isoobtusadiene (1), its unreported acetyl derivative (2), and the known (+)-elatol (3). The complete elucidation of the structures 1 and 2 was accomplished by 1D and 2D NMR spectroscopy. The first assignment of the absolute configuration of the isoobtusadiene skeleton is suggested as 6S,9R,10S on the basis of the NMR analysis of the Mosher's ester derivatives of 1 and the ECD study of the acetyl derivative 2. Chamigrenes are typical constituents of Laurencia red algae. O. reticulata is a predator with a preference for algae. Thus, the origin of these metabolites can be likely ascribed to diet.

Purification, Biochemical Characterization, and Amino Acid Sequence of a Novel Type of Lectin from Aplysia dactylomela Eggs with Antibacterial/Antibiofilm Potential.

A new lectin from Aplysia dactylomela eggs (ADEL) was isolated by affinity chromatography on HCl-activated Sepharose™ media. Hemagglutination caused by ADEL was inhibited by several galactosides, mainly galacturonic acid (Ka = 6.05 × 106 M-1). The primary structure of ADEL consists of 217 residues, including 11 half-cystines involved in five intrachain and one interchain disulfide bond, resulting in a molecular mass of 57,228 ± 2 Da, as determined by matrix-assisted laser desorption/ionization time of flight mass spectrometry. ADEL showed high similarity with lectins isolated from Aplysia eggs, but not with other known lectins, indicating that these lectins could be grouped into a new family of animal lectins. Three glycosylation sites were found in its polypeptide backbone. Data from peptide-N-glycosidase F digestion and MS suggest that all oligosaccharides attached to ADEL are high in mannose. The secondary structure of ADEL is predominantly ß-sheet, and its tertiary structure is sensitive to the presence of ligands, as observed by CD. A 3D structure model of ADEL was created and shows two domains connected by a short loop. Domain A is composed of a flat three-stranded and a curved five-stranded ß-sheet, while domain B presents a flat three-stranded and a curved four-stranded ß-sheet. Molecular docking revealed favorable binding energies for interactions between lectin and galacturonic acid, lactose, galactosamine, and galactose. Moreover, ADEL was able to agglutinate and inhibit biofilm formation of Staphylococcus aureus, suggesting that this lectin may be a potential alternative to conventional use of antimicrobial agents in the treatment of infections caused by Staphylococcal biofilms.

New records of ribbon worms (Nemertea) from Ceará, Northeast Brazil.

Of 45 species of nemerteans reported for the Brazilian coast, only two were recorded from Brazil's Northeast coast. Here we report seven new records for the state of Ceará, in Northeast Brazil: Tubulanus rhabdotus Côrrea, 1954, Carinomella cf. lactea Coe, 1905, Baseodiscus delineatus (Delle-Chiaje 1825), Cerebratulus cf. lineolatus Coe, 1905, Cerebratulus sp. 1, Cerebratulus sp. 2 and Lineidae sp. 1. Specimens were collected at the following beaches: Praia dos Dois Coqueiros, Praia do Pacheco, Pecém harbor, Praia da Pedra Rachada and Praia do Guajiru. T. rhabdotus is a new record for Northeast Brazil, Carinomella cf. lactea and Cerebratulus cf. lineolatus are new records for the South Atlantic Ocean and both genera are new records for Brazil.

Pugilina morio L., a new imposex exhibitor from South American estuarine environments: approach for a non-lethal method to evaluate imposex.

This is the first report on imposex occurrence in Pugilina morio. Imposex levels in P. morio from Ceará River Estuary were assessed by a non-lethal method. The obtained imposex parameters were: percentage = 37.1 %, female penis length index (FPLI) = 0.93 mm, relative penis length index (RPLI) = 6.5 %, and vas deferens sequence index (VDSI) = 1.0. Because imposex is induced by tributyltin, and P. morio is widely distributed on the East coast of South America, the species can be used as a tributyltin contamination sentinel in these estuaries. Additionally, a non-lethal method of evaluating imposex minimized the impact on the population of P. morio from sample collection, as all organisms were returned to the environment.

Description of the ootheca of Turbinella laevigata (Mollusca, Gastropoda)

Turbinella laevigata is found since the intertidal zone up to 40 m depth, being endemic of Brazil where it occurs from the state of Amapá to the state of Espirito Santo. The objective of this study was to describe the ootheca of this species. Fifteen samples collected in the Olho d'Água Beach, City of Icapuí and Fleixeiras Beach, City of Trairí, both in Ceará State, Northeast Brazil, were studied. The spawns were composed by 15 +/- 1.4 SD capsules and had 63 +/- 6.4 SD mm of length with 41 +/- 2.5 SD mm of width. They had a convex and a concave surface, and plaited edges that drew out until the basal membrane, to which they joined forming a medial ridge. This species apparently produced a high amount of nurse eggs. The early juveniles measured 6.4 +/- 0.7 SD mm of length and they presented a protoconch with three whorls.

Turbinella laevigata é encontrada desde a zona entre marés até 40 m de profundidade, sendo endêmica do Brasil onde ocorre desde o Estado do Amapá até o Espírito Santo. O objetivo deste estudo foi descrever a ooteca de Turbinella laevigata. Quinze amostras foram coletadas na Praia de Olho d'Água, Município de Icapuí e na Praia de Flexeiras, Município do Trairí, ambos no Estado do Ceará, Nordeste do Brasil, foram estudadas. As desovas de T. laevigata foram compostas por 15 +/- 1.4 SD cápsulas e mediram 63 +/- 6.4 SD mm de comprimento e 41 +/- 2.5 SD mm de largura. Todas as cápsulas estavam fixadas pela membrana basal, a qual tinha a extremidade modificada para se prender ao substrato. Elas possuem uma superfície concava e outra convexa, apresentando margens pregueadas, que se prolongavam até a membrana basal, à qual se uniam formando uma prega. Esta espécie aparentemente produz uma grande quantidade de ovos nutritivos. A concha dos juvenis mediu 6.4 +/- 0.7 SD mm de comprimento e apresentou uma protoconcha com 3 voltas.

Imposex in endemic volutid from Northeast Brazil (Mollusca: Gastropoda)

Imposex is characterized by the development of masculine sexual organs in neogastropod females. Almost 120 mollusk species are known to present imposex when exposed to organic tin compounds as tributyltin (TBT) and triphenyltin (TPT). These compounds are used as biocide agents in antifouling paints to prevent the incrustations on boats. Five gastropod species are known to present imposex in Brazil: Stramonita haemastoma, Stramonita rustica, Leucozonia nassa, Cymathium parthenopeum and Olivancillaria vesica. This paper reports the first record of imposex observed in the endemic gastropod Voluta ebraea from Pacheco Beach, Northeast Brazil. Animals presenting imposex had regular female reproductive organs (capsule gland, oviduct and sperm-ingesting gland) and an abnormal penis. As imposex occurs in mollusks exposed to organotin compounds typically found at harbors, marinas, shipyards and areas with high shipping activities, probably contamination of Pacheco Beach is a consequence of a shipyard activity located in the nearest areas.

O imposex caracteriza-se pelo surgimento de estruturas sexuais masculinas, em fêmeas de gastrópodes. Cerca de 120 espécies de moluscos que exibem o fenômeno quando expostas a contaminação por compostos orgânicos de estanho tais como o Tributilestanho (TBT) e o Trifenilestanho (TPT). Esses compostos são utilizados, sobretudo em embarcações, no intuito de evitar a bioincrustração que danifica as embarcações e eleva os custos das viagens marítimas. No Brasil se conhecem 5 espécies de moluscos gastrópodes que manifestam imposex, são elas: Stramonita haemastoma, Stramonita rustica, Leucozonia nassa, Cymathium parthenopeum e Olivancillaria vesica. No Nordeste, monitoramentos da contaminação por organoestânicos foram realizados utilizando o imposex em gastrópodes como biomarcador. O presente estudo tem por objetivo notificar a primeira ocorrência de imposex na espécie endêmica do Nordeste brasileiro, Voluta ebraea. De um total de 11 animais observados, duas fêmeas apresentaram imposex, provenientes da Praia do Pacheco no litoral do Ceará. Observou-se nesses indivíduos a presença de glândula de cápsulas, ovidutos e receptáculo seminal concomitantemente ao pênis o que caracteriza o imposex. Como o imposex só se manifesta em moluscos expostos a compostos organoestânicos tipicamente encontrados em portos, marinas, estaleiros e locais com grande fluxo de embarcações atribui-se a origem dessa contaminação provavelmente a um estaleiro localizado nas proximidades da área de coleta.

A survey of the Scyphozoa and Cubozoa (Cnidaria, Medusozoa) from the Ceará coast (NE Brazil) / Levantamento de Scyphozoa e Cubozoa (Cnidaria, Medusozoa) do litoral do Ceará (NE do Brasil)

Most of the scyphozoans and cubozoans recorded for the Brazilian coast are presumed to be distributed over the entire coastline, but little information on precise records is available. This paper presents the first published records for the Ceará state (northeastern region) of the cubozoan Chiropsalmus quadrumanus, and the scyphozoans Chrysaora lactea, Linuche unguiculata (polyp), Lychnorhiza lucerna, Nausithoe sp. (polyp), Phyllorhiza punctata, and Stomolophus meleagris. The medusoid species have been known by local fishermen and non-specialists for a long time in the area.

A maioria das cifomedusas e cubomedusas registradas para o litoral brasileiro é presumivelmente distribuída por toda a costa; porém poucos registros precisos estão disponíveis. Este estudo apresenta os primeiros registros publicados para o estado do Ceará (região Nordeste) da cubomedusa Chiropsalmus quadrumanus, e dos cifozoários: Chrysaora lactea, Linuche unguiculata (pólipo), Lychnorhiza lucerna, Nausithoe sp. (pólipo), Phyllorhiza punctata and Stomolophus meleagris. As espécies de medusas são conhecidas de longa data por pescadores locais e não-especialistas no grupo.

Os gêneros Fasciolaria Lamarck, 1799 e Leucozonia Gray, 1847 no nordeste brasileiro (Mollusca: Gastropoda: Fasciolariidae) / The genera Fasciolaria Lamarck, 1799 and Leucozonia Gray, 1847 in the northeastern Brazil (Mollusca: Gastropoda: Fasciolariidae)

The genera Fasciolaria Lamarck, 1799 and Leucozonia Gray, 1847 are represented in Northeastern Brazil by three species. Fasciolaria aurantiaca Lamarck, 1816; Leucozonia ocellata (Gmelin, 1791) and Leucozonia nassa (Gmelin, 1791). The three species are described and illustrated. An identification key for all the above mentioned taxa is included, together with some ecological data. The anatomy and radula of Fasciolaria aurantiaca and Leucozonia nassa are described and illustrated. Polimorfism in Fasciolaria aurantiaca and Leucozonia nassa is discussed.