South American Atlantic Coast Research Articles

Native hybrid carrageenans from Sarcopeltis skottsbergii and Sarcothalia crispata: The role of counterions on their gelling properties

Carrageenans are red seaweed polysaccharides of great importance as gelling agents in the food texture market. The hybrid kappa/iota-carrageenan is extracted from certain cold-water species and its unique properties have given rise to growing demand for this biopolymer. Gelation of these polysaccharides is affected by the valency and, sometimes, the identity of counterions. The main objectives of this work were to investigate the role of potassium and calcium ions on the gelation of the native hybrid carrageenans from Sarcopeltis skottsbergii and Sarcothalia crispata from the South American Atlantic coast, and to optimize the structural properties of these gels. Response surface methodology was used to analyze the effects of carrageenan concentration, salt concentration, and KCl:CaCl2 ratio, on the rheology, texture, syneresis after 50 % deformation, and color of these gels. Both native carrageenans presented high extraction yield (42.73 ± 0.20 g/100 g for S. skottsbergii and 20.43 ± 7.64 g/100 g for S. crispata) and formed either weak or strong gels upon the addition of salt. Carrageenan and salt concentrations increased gel strength, but also increased turbidity. Moreover, KCl fraction also increased gel strength, attributed to the predominance of the kappa diad in these carrageenans, whose gelation is favored by potassium ions. All samples showed syneresis after deformation, being minimized with higher carrageenan and salt contents. Optimal compositions predicted by the selected models to maximize gel strength and minimize syneresis and haze, were 1.13 % carrageenan, 0.39 M salt and a proportion of 0.85 KCl for S. skottsbergii, and 1.16 % carrageenan, 0.36 M salt and a proportion of 0.85 KCl for S. crispata. Predicted responses for these optimal compositions were in accordance with the observed responses. Considering the worldwide growing demand for kappa/iota-carrageenan in the food industry, S. skottsbergii and S. crispata from the South Atlantic represent a potential source of these biopolymers.

Speciation in Coastal Basins Driven by Staggered Headwater Captures: Dispersal of a Species Complex, Leporinus bahiensis, as Revealed by Genome-wide SNP Data.

Past sea level changes and geological instability along watershed boundaries have largely influenced fish distribution across coastal basins, either by dispersal via palaeodrainages now submerged or by headwater captures, respectively. Accordingly, the South American Atlantic coast encompasses several small and isolated drainages that share a similar species composition, representing a suitable model to infer historical processes. Leporinus bahiensis is a freshwater fish species widespread along adjacent coastal basins over narrow continental shelf with no evidence of palaeodrainage connections at low sea level periods. Therefore, this study aimed to reconstruct its evolutionary history to infer the role of headwater captures in the dispersal process. To accomplish this, we employed molecular-level phylogenetic and population structure analyses based on Sanger sequences (5 genes) and genome-wide SNP data. Phylogenetic trees based on Sanger data were inconclusive, but SNPs data did support the monophyletic status of L. bahiensis. Both COI and SNP data revealed structured populations according to each hydrographic basin. Species delimitation analyses revealed from 3 (COI) to 5 (multilocus approach) MOTUs, corresponding to the sampled basins. An intricate biogeographic scenario was inferred and supported by Approximate Bayesian Computation (ABC) analysis. Specifically, a staggered pattern was revealed and characterized by sequential headwater captures from basins adjacent to upland drainages into small coastal basins at different periods. These headwater captures resulted in dispersal throughout contiguous coastal basins, followed by deep genetic divergence among lineages. To decipher such recent divergences, as herein represented by L. bahiensis populations, we used genome-wide SNPs data. Indeed, the combined use of genome-wide SNPs data and ABC method allowed us to reconstruct the evolutionary history and speciation of L. bahiensis. This framework might be useful in disentangling the diversification process in other neotropical fishes subject to a reticulate geological history.

Microplastic contamination in large migratory fishes collected in the open Atlantic Ocean

Fishes are one of the most important components of the oceans and are exposed to several anthropogenic pressures, namely microplastic (MP), contaminants that are now ubiquitous worldwide. Taking advantage of the 2020 Circumnavigation Expedition carried by the NRP Sagres tall ship of the Portuguese Navy, fish samples from the southern Atlantic ocean were collected to evaluate possible MP contamination. In a total of 14 weeks of campaign, seven large migratory fishes of commercial interest were collected across the middle Atlantic Ocean and along the South American Atlantic coast. All individuals were contaminated with MPs, with an average of 18 ± 11 MPs/fish. In all fish sampled, both the gastrointestinal tract and gills presented MPs, indicating different contamination pathways including via their preys and from surrounding water, respectively. A total of 124 MPs were observed, where 72 % were fibers and 28 % particles, mostly of blue color (85 %), and with rayon and nylon as the most abundant polymers. This study is an important contribution to increase the scientific knowledge of MP contamination in mesopelagic fishes used for human consumption and collected in the open waters, reinforcing the need for further research regarding MP contamination in top predatory species from high trophic levels.

Chromosome-level genome assembly of the blue crab, Callinectes sapidus.

The blue crab, Callinectes sapidus (Rathbun, 1896) is an economically, culturally, and ecologically important species found across the temperate and tropical North and South American Atlantic coast. A reference genome will enable research for this high-value species. Initial assembly combined 200× coverage Illumina paired-end reads, a 60× 8 kb mate-paired library, and 50× PacBio data using the MaSuRCA assembler resulting in a 985 Mb assembly with a scaffold N50 of 153 kb. Dovetail Chicago and HiC sequencing with the 3d DNA assembler and Juicebox assembly tools were then used for chromosome scaffolding. The 50 largest scaffolds span 810 Mb are 1.5–37 Mb long and have a repeat content of 36%. The 190 Mb unplaced sequence is in 3921 sequences over 10 kb with a repeat content of 68%. The final assembly N50 is 18.9 Mb for scaffolds and 9317 bases for contigs. Of arthropod BUSCO, ∼88% (888/1013) were complete and single copies. Using 309 million RNAseq read pairs from 12 different tissues and developmental stages, 25,249 protein-coding genes were predicted. Between C. sapidus and Portunus trituberculatus genomes, 41 of 50 large scaffolds had high nucleotide identity and protein-coding synteny, but 9 scaffolds in both assemblies were not clear matches. The protein-coding genes included 9423 one-to-one putative orthologs, of which 7165 were syntenic between the two crab species. Overall, the two crab genome assemblies show strong similarities at the nucleotide, protein, and chromosome level and verify the blue crab genome as an excellent reference for this important seafood species.

Reproductive potential and early spore settlement on different substrates in Gigartina skottsbergii (Gigartinaceae, Rhodophyta) from the South American Atlantic coast

The aims of this study were to estimate seasonal spore availability in the carrageenophyte Gigartina skottsbergii from the Patagonian Atlantic coast, evaluate the effect of induction methods and culture conditions on spore release, and assess spore settlement on different substrates. Fertile fronds were collected in southern Argentina. The density and size of reproductive structures and spore output were registered seasonally. Spore release was evaluated using different induction methods and conditions. Finally, different natural substrates were assessed for spore settlement. Spore availability is restricted to winter and spring. Cystocarps and tetrasporangial sori reached maturity towards winter, and spores were released in large amounts during winter and spring, with higher tetraspore than carpospore release. Spontaneous discharge would appear to be a more advisable induction method than desiccation and high salinity. Temperature and photoperiod did not have a significant effect on total spore output. After 2 weeks of incubation, no differences were found among spore densities on glass, pebbles, clams, or mussels. Despite the low survival rate registered on all substrates, spores germinated and developed healthily. This is the first study to evaluate carpospore and tetraspore availability throughout the year and the viability of in vitro spore culture of G. skottsbergii from the South American Atlantic coast.

How oogenesis analysis combined with DNA barcode can help to elucidate taxonomic ambiguities: a polychaete study-based approach

Abstract: Polychaetes are common in coastal and estuarine environments worldwide and constitute one of the most complex groups of marine invertebrates. The morpho-physiology of the female reproductive system (FRS) can be understood by using histological tools to describe reproductive cycle and gametogenesis paths and, among other purposes, aiming to identify and differentiate polychaete species. However, this histology-based approach is rarely combined with molecular tools, which is known to accurately delimitate species. In the same way, the description and understanding of oogenesis and vitellogenesis paths within polychaetes are lacking for most families, narrowing the range of its utility. Therefore, the present study aims to describe the oogenesis in three polychaete species common and abundant on the South American Atlantic coast (Laeonereis culveri, Scolelepis goodbodyi and Capitella biota) and investigate the utility of reproductive features and gametogenesis as a relevant associate knowledge to discriminate species, particularly useful for putative cryptic species, integrated with morphological and molecular data. In a first attempt, the results obtained herein allow the authors to describe two new subtypes of oogenesis, dividing it in extraovarian oogenesis type I and II and intraovarian type I and II. The results also demonstrate that the following histological characters of the FRS can be relevant for the separation of related species: a) oogenesis type, b) occurrence or absence of a true ovary, c) ovary tissue organization, d) type of accessory cells present, and e) oocyte morphology. Additionally, these histological features of FRS, when compared with correlated species studied under this scope, converge with the genetic data. The analysis of cytochrome oxidase I (COI) barcode sequences differentiates between North and South American Atlantic populations of L. culveri (16.78% genetic distance), while in S. goodbodyi and C. biota it discriminates them from their congeneric species. These results highlight the importance of multi-tool approach and shows that both FRS histology and histo-physiology, and DNA barcoding can be used to identify and discriminate cryptic species, which is usually not possible when using morphological characters. Besides, these characters may also be useful in differentiating related species, and/or geographically distinct populations among polychaetes.

A new species of Miobantia Giglio-Tos, 1917 with a novel morphological feature (Mantodea: Thespidae: Miobantiinae).

Thespidae is the most diverse family among the Neotropical Mantodea, currently containing 33 genera and 146 species of praying mantises (Wieland Svenson, 2018). Miobantia Giglio-Tos, 1917 are small, dark coloured mantids, often found in low vegetation of humid forests near the South American Atlantic coast, from the Brazilian Northeast to the Argentine Patagonia (Scherrer, 2014). Males are active fliers, while females, apterous, are often found in leaf litter or in plants close to the ground (Scherrer, 2014; Santos et al., 2018). Despite their commonness in the Brazilian Atlantic Forest the genus received little taxonomic attention, yet had a complicated nomenclatural history. Scherrer (2014) provided a comprehensive taxonomic and nomenclatural revision of Miobantia after incorporating both molecular and morphological data to reorganize the group, resulting in the description of four new species, detailed identification keys, illustrations, association of conspecific sexes, and maps for all known species. The most recent contribution to the taxonomy of the genus was the addition of Metathespis precaria Piza, 1968 as a junior synonym of Miobantia rustica (Fabricius, 1781) (Agudelo Rivera, 2015).

Reconstructing biogeographic temporal events in the evolution of the livebearer fish genus Jenynsia based on total evidence analysis (Cyprinodontiformes: Anablepidae)

The current distribution of the Neotropical ichthyofauna has been widely affected by the main geological events that occurred in South and Central America. However, robust biogeographic information is still scarce or absent for most fish families. The biogeographic relationships of the most diverse anablepid genus, Jenynsia, are herein analysed, using temporal and spatial approaches based on a total evidence dataset, including 167 morphological characters and seven nuclear genes, totalling 6075 bp. A time calibrated analysis recovered the origin of Jenynsia at the Miocene and the diversification of its two subgenera between the Late Miocene and Early Pliocene. This result combined with the analysis of reconstruction of ancestral states indicates that the ancestor of Jenynsia colonized the Paranean Sea, and the current distribution of the species of the genus is probably a result of geological events, including: (1) ancient connections between Iguaçu and upper Uruguay River basins; (2) sea level variation along the Pliocene in the South American Atlantic coast; and (3) the decrease of the Paranean Sea along the Pliocene and Pleistocene.

Single nucleotide polymorphisms in native South American Atlantic coast populations of smooth shelled mussels: hybridization with invasive European Mytilus galloprovincialis

BackgroundThroughout the world, harvesting of mussels Mytilus spp. is based on the exploitation of natural populations and aquaculture. Aquaculture activities include transfers of spat and live adult mussels between various geographic locations, which may result in large-scale changes in the world distribution of Mytilus taxa. Mytilus taxa are morphologically similar and difficult to distinguish. In spite of much research on taxonomy, evolution and geographic distribution, the native Mytilus taxa of the Southern Hemisphere are poorly understood. Recently, single nucleotide polymorphisms (SNPs) have been used to clarify the taxonomic status of populations of smooth shelled mussels from the Pacific coast of South America. In this paper, we used a set of SNPs to characterize, for the first time, populations of smooth shelled mussels Mytilus from the Atlantic coast of South America.ResultsMytilus spp. samples were collected from eastern South America. Six reference samples from the Northern Hemisphere were used: Mytilus edulis from USA and Northern Ireland, Mytilus trossulus from Canada, and Mytilus galloprovincialis from Spain and Italy. Two other reference samples from the Southern Hemisphere were included: M. galloprovincialis from New Zealand and Mytilus chilensis from Chile. Fifty-five SNPs were successfully genotyped, of which 51 were polymorphic. Population genetic analyses using the STRUCTURE program revealed the clustering of eight populations from Argentina (Mytilus platensis) and the clustering of the sample from Ushuaia with M. chilensis from Chile. All individuals in the Puerto Madryn (Argentina) sample were identified as M. platensis × M. galloprovincialis F2 (88.89%) hybrids, except one that was classified as Mediterranean M. galloprovincialis. No F1 hybrids were observed.ConclusionsWe demonstrate that M. platensis (or Mytilus edulis platensis) and M. chilensis are distinct native taxa in South America, which indicates that the evolutionary histories of Mytilus taxa along the Atlantic and Pacific coasts differ. M. platensis is endangered by hybridization with M. galloprovincialis that was introduced from Europe into the Puerto Madryn area in Argentina, presumably by accidental introduction via ship traffic. We confirm the occurrence of a native M. chilensis population in southern Argentina on the coast of Patagonia.

Evidence of an Marine Isotope Stage 3 transgression at the Baixada Santista, south-eastern Brazilian coast

ABSTRACT: In this paper, we present new evidence regarding a Marine Isotope Stage 3 (MIS3) transgression on the south-eastern Brazilian coast (Baixada Santista coastal plain). Data collected from a Standard Penetration Test (SPT) drilling reveal the occurrence of myxohaline sediments between cal BP 45,000 and 41,000. A deeper sequence, which shows a clear transition from terrestrial to a myxohaline environment, was associated with MIS5e. Organic and inorganic proxies have been used to recognize the variations on the terrestrial/myxohaline/marine deposits, as well as to infer about climate and energy of the depositional environment. Environmental change, which could correspond to a sea-level peak or the occurrence of drier conditions, was recognized between 43,000 and 42,000 cal BP. The results reinforce the need for future works on MIS3 variability on the South American Atlantic coast.

Genetically diverse herpesviruses in South American Atlantic coast seabirds.

Different herpesviruses have been associated with respiratory and enteric disease and mortality among seabirds and waterfowl. In 2011, a respiratory disease outbreak affected 58.3% (98/168) of the Magellanic penguins undergoing rehabilitation due to an oil spill off the southern Brazilian coast. Etiology was attributed to a novel herpesvirus identified by histopathology, immunohistochemistry, electron microscopy and molecular studies with partial DNA sequencing. Since migration, rehabilitation and translocation may facilitate the spread of pathogens between populations and trigger the onset of clinical disease in animals with latent infections, investigation of herpesvirus occurrence in asymptomatic seabirds was performed. Samples from free-ranging seabirds were collected in Argentinian Patagonia (Magellanic penguins) and the Abrolhos Archipelago in Brazil (Brown boobies, Masked boobies, Red-billed tropicbirds, White-tailed tropicbirds and South American tern). Furthermore, asymptomatic seabirds housed at the facility where the outbreak occurred were also sampled. In total, 354 samples from eight seabird species were analyzed by PCR for herpesvirus. Four different sequences of herpesviruses were identified, one in Yellow-nosed Albatross, one in Boobies and Tropicbirds and two in Magellanic penguins. Magellanic penguin herpesvirus 1 was identified during the penguin outbreak at the rehabilitation facility in Brazil, while Magellanic penguin herpesvirus 2 was recovered from free-ranging penguins at four reproduction sites in Argentina. Phylogenic analysis of the herpesviruses sequences tentatively identified suggested that the one found in Suliformes and the one associated with the outbreak are related to sequences of viruses that have previously caused seabird die-offs. These findings reinforce the necessity for seabird disease surveillance programs overall, and particularly highlight the importance of quarantine, good hygiene, stress management and pre-release health exams in seabirds undergoing rehabilitation.

Pan-American marine coastal distribution of the acanthocephalanProfilicollis altmanibased on morphometric and phylogenetic analyses of cystacanths from the mole crabEmerita brasiliensis

Thorny-headed acanthocephalan worms of the genus Profilicollis are widely distributed in the oceans of the world and present complex life cycles with intermediate and definitive hosts. The genus is still poorly known, with an unstable taxonomy and, for most species, incompletely characterized geographical distributions. In this study, based on molecular and morphological evidence, we report that the species Profilicollis altmani is also distributed along the South American Atlantic coast, using the mole crab Emerita brasiliensis as an intermediate host. As such, our record shows that P. altmani has a Pan-American distribution where five species of Emerita are utilized as intermediate hosts.

Identification of the Toxic Pentapeptide Nodularin in a Cyanobacterial Bloom in a Shrimp Farm in South American Atlantic Coast

Since 2010, blooms of the brackish cyanobacteria Nodularia spumigena are recurrent in the shrimp growth tanks of the Marine Aquaculture Station during summer in Southern Brazil. Cyanobacterial growth led to a decrease in the white shrimp Litopenaeus vannamei productivity. In the summer of 2014, a Nodularia bloom was collected from the tanks; filaments were separated by flotation and washed thoroughly twice in F/2 culture medium. Healthy filaments were lyophilized and the powder used for nodularin quantification by HPLC-DAD and immunoassays. Nodularin containing lyophilized powder was also tested for toxicity against the brine shrimp Artemia salina post-larvae and the white shrimp Litopenaeus vannamei 35 days old larvae. The lyophilized Nodularia powder contained 1.88 mg of the toxin nodularin g-1d.w. Its toxicity was confirmed in bioassays with Artemia salina and Litopenaeus vannamei giving an LC50 of 1.22 and 2.50 μgL-1 of nodularin, respectively. This paper firstly describes the occurrence and the toxicity of nodularin in South Atlantic coastal waters with consequences to shrimp farming.

First occurrence of Beroe forskalii (Ctenophora) in South American Atlantic coastal waters, with notes on the use of macrociliary patterns for beroid identification.

Beroe forskalii Milne Edwards, 1841 is an oceanic ctenophore with a global distribution. The present study provides the first record of Beroe forskalii for the South American Atlantic coast, including a redescription of the species and a discussion on the utility of macrociliary patterns for the correct identification of at least some beroid species, exemplified by a comparison of the macrociliary patterns of Beroe forskalii and Beroe ovata (Chamisso & Eysenhardt, 1821).

Population Dynamics and Diet of the Madamango Sea Catfish Cathorops spixii (Agassiz, 1829) (Siluriformes: Ariidae) in a Tropical Bight in Southeastern Brazil

The madamango sea catfish, Cathorops spixii (Siluriformes: Ariidae), is often among the most abundant fishes on the South American Atlantic coast. In the present study, conducted in shallow, non-estuarine coastal areas of Caraguatatuba Bight in southeastern Brazil, collections of this species, the most abundant member of the ichthyofauna, included primarily medium-sized individuals, indicating that the area may play a specific role in their development. Although studies of the local ichthyofauna have been much neglected, the area is economically important and its ecological significance is undervalued. This study primarily treats habitat use by C. spixii, assessing certain population parameters and the dietary composition. Monthly samples were taken from August 2003 through October 2004, with three trawls in two areas, corresponding to depths of about 1 to 4 m. The catfish showed two main peaks of abundance in the area, in April/May and July 2004. A mode around 9 cm SL persisted through time, and the entrance of younger recruits peaked from January to April. The low estimate for body-growth parameters (K = 0.16) corroborates some K-strategist characteristics of the species. The asymptotic length was 27.3 cm SL and total mortality (Z) was 1.01 yr−1. Cathorops spixii showed an omnivorous feeding habit, preying mainly upon polychaetes, copepods and bivalves, with considerable seasonality in its diet.

Feeding ecology of Kelp Gulls (Larus dominicanus) in marine and limnetic environments

The diet of the Kelp Gull (Larus dominicanus) was investigated at the northern limit of its distribution along the South American Atlantic coast. We used two complementary methods, pellet analysis and stable isotope analysis (SIA), to describe and compare Kelp Gull feeding ecology in freshwater and marine environments. The assimilated diet over two different time scales was investigated via SIA of plasma and red blood cells, blood components with different turnover rates. Fish composed the bulk of the diet of Kelp Gulls in both marine (White Croaker Micropogonias furnieri and Banded Croaker Paralonchurus brasiliensis) and limnetic areas (Armoured Catfish Loricariidae and La Plata Croaker Pachyurus bonariensis), despite the importance of benthic prey from the intertidal zone in samples collected from the marine environment (Wedge Clam Donax hanleyanus and the Yellow Clam Mesodesma mactroides). The fish consumed by the gulls were common discards from fisheries in both environments, and marine bivalves were found at a high density at the marine beach. Diet varied between the different time scales analysed. Conventional diet data generally agreed with stable isotope model estimates, emphasising the importance of using complementary approaches in dietary studies.

BIOGEOGRAPHY AND CONNECTIVITY BETWEEN WESTERN SOUTH AMERICAN AND ANTARCTIC MARINE MOLLUSCS

table.MsoNormalTable { font-size: 10pt; font-family: Times New Roman,serif; } The latitudinal diversity gradient is widely recognized, leading researchers to assume that Antarctic fauna are impoverished. However, with increased sampling efforts, some studies have shown a great diversity of certain marine groups surrounding the Antarctic continent, with higher rates of them. Antarctic endemism may be associated with its isolation and climate change over the evolutionary time scale. Despite this relative isolation, recent evidence suggests some degree of connectivity between the Antarctic and South American faunas. Our study used secondary data extracted from Malacolog 4.1.1. The geographical area considered was the entire South American Atlantic coast and the the adjacent areas of the Antarctic (Antarctic Peninsula, part of the Weddell Sea and islands of the Scotia Arc). Our survey yielded 6517 species of mollusks. The most diverse province was the North Brazil Shelf, and the least diverse was the Scotia Sea. Endemism rates for low-latitude provinces were close to 15%, in contrast to the highest endemism rate of 40% in the Scotia Sea Province. The highest value for richness was found for the Guianan ecoregion, and the lowest value for the Antarctic Peninsula. Most ecoregions had an endemism rate around 3%, with the highest endemism in South Georgia. The richness gradient increased toward lower latitudes. The cluster analysis for the malacofauna indicated four statistically significant groups. The bathymetric Rapoport´s Rule showed the increase of bathymetric range toward higher-latitude ecoregions and whereas Bergmann´s Rule showed the opposite relationship. The higher richness at -25 o S may be associated with the presence of coral and calcareous algal reefs. At mid-latitudes richness was also high, and this region comprise an ecotone between thermophilic and cryophilic species'. The cluster analysis validated three provinces proposed by Spalding (2007), although it revealed the inadequate knowledge of the North Brazil Shelf province. The higher endemism observed in the Magellanic and Scotia seas demonstrates the influence that Antarctic isolation has on its community structure, although the cluster showed the existence of a connection with South America. The observed converse Bergmann´s Rule could be explained by the shorter seasons at higher latitudes, which limit the phenotypic body size that can be attained.

A new species of Dichelyne (Nematoda, Cucullanidae) parasitizing sciaenid fishes from off the South American Atlantic coast

AbstractA new nematode species Dichelyne (Cucullanellus) sciaenidicola sp. nov. is described based on specimens collected from the Whitemouth croaker Micropogonias furnieri (Desmarest) and the Argentine croaker Umbrina canosai Berg, from coastal waters of Argentina and Brazil. These nematodes were firstly identified as D. (C.) elongatus (Törnquist, 1931), a commonly reported species from M. furnieri in South American Atlantic waters. However, other species of Dichelyne have so far been reported from this host in the same area, namely D. (C.) rodriguesi (Pinto, Fábio et Noronha, 1970), D. (C.) amaruincai (Freitas, Vicente et Ibañez, 1969) and D. (Dichelyne) micropogonii Pereira et Costa, 1996. A careful re-examination of these parasites, as well as of type specimens of all species reported from M. furnieri, revealed that these nematodes represented a new species. The new species is distinguished from most of its congeners by having papillae 5–7 and 9 forming a subventral line close to cloaca, this feature is shared with other 6 species [D. (C.) dichelyneformis (Szidat, 1950), D. (C.) fraseri (Baylis, 1929), D. (C.) abbreviatus (Rudolphi, 1819), D. (C.) adriaticus (Törnquist, 1931), D. (C.) minutus (Rudolphi, 1819) and D. (C.) mariajuliae Alarcos, Timi, Etchegoin et Sardella, 2006)], which are readily distinguished by their body size, spicules length, distribution patterns of other papillae and position of the excretory pore and deirids. Also, D. (C.) elongatus from Umbrina canariensis (Valenciennes) from West Africa is established as a new species Dichelyne (Cucullanellus) yvonnecampanae sp. nov.; D. (C.) amaruincai from Pacific waters is considered as a valid species, D. (D.) micropogonii is regarded as species inquirendae and D. (C.) rodriguesi is identified as Cucullanus sp.

On the protection of "protected areas".

Tropical moist forests contain the majority of terrestrial species. Human actions destroy between 1 and 2 million km(2) of such forests per decade, with concomitant carbon release into the atmosphere. Within these forests, protected areas are the principle defense against forest loss and species extinctions. Four regions-the Amazon, Congo, South American Atlantic Coast, and West Africa-once constituted about half the world's tropical moist forest. We measure forest cover at progressively larger distances inside and outside of protected areas within these four regions, using datasets on protected areas and land-cover. We find important geographical differences. In the Amazon and Congo, protected areas are generally large and retain high levels of forest cover, as do their surroundings. These areas are protected de facto by being inaccessible and will likely remain protected if they continue to be so. Deciding whether they are also protected de jure-that is, whether effective laws also protect them-is statistically difficult, for there are few controls. In contrast, protected areas in the Atlantic Coast forest and West Africa show sharp boundaries in forest cover at their edges. This effective protection of forest cover is partially offset by their very small size: little area is deep inside protected area boundaries. Lands outside protected areas in the Atlantic Coast forest are unusually fragmented. Finally, we ask whether global databases on protected areas are biased toward highly protected areas and ignore "paper parks." Analysis of a Brazilian database does not support this presumption.

Causes and contrasts in current and past distribution of the white shark (Lamniformes: Carcharodon carcharias) off southeastern South America

The great white shark is a cosmopolitan temperate marine species which is rare in Argentina, Uruguay, and Brazil today. Several publications include the white shark as inhabiting Patagonian waters. However, there is no recent or fossil record of the white shark south of S 38° 30´ in the southwestern Atlantic. A tooth found in Quaternary sediments at Pehuencó (S 38° 56´), southern Buenos Aires province, is the southernmost occurrence of the species in the southwestern Atlantic. The occurrence of C. carcharias in the Buenos Aires province is another confirmation that the Argentine biogeographic province extends to the south of the Río de la Plata. The present extremely scarce record indicates that there are not permanent living populations in the South American Atlantic coast but occasional transient individuals. However, the abundant fossil and archaeological record suggests that it was much more common in southwestern Atlantic during the late Pleistocene and Holocene than today. This drop in abundance is here mostly attributed to the massive extermination of pinnipeds and cetaceans during the XIXth and XXth centuries. Patagonian waters, where marine mammals are relatively abundant even today, might be too cold for the species which is mostly encountered between 15-23°C. Besides, another important predator, the killer whale, which also feeds on marine mammals, is frequently found in these waters. Consequently, available evidence suggests that unrestricted hunting of pinnipeds and cetaceans also decimated another animal, a fish.