Abstract Bioseston is a heterogeneous assemblage of bacterioplankton, phytoplankton, zooplankton, and planktonic debris. A detailed knowledge of biosestons is essential for understanding the dynamics of trophic flows in marine ecosystems. The distributional features of seston biomass in plankton (micro- and mesoplankton) in the Southwest Atlantic Ocean (Rio de Janeiro State, Brazil) were analyzed using stratified samples gathered to a depth of 2,400 m during night time. The horizontal pattern of biomass distribution was analyzed vis-a-vis station depth during both wet and dry periods, with higher values recorded in the continental shelf than in the slope, confirming the terrestrial contribution of nutrient sources to the marine environment. This horizontal variation reinforces the occurrence of seasonal vortices in Cabo Frio and Cabo de São Tomé on the central coast of Brazil. Environmental variables reflect the hydrological signatures of the water masses along the Brazilian coast. The largest seston biomass was related to high temperatures, salinities, and low inorganic nutrient concentrations in tropical and South Atlantic central waters. The observed distribution patterns suggest that seston biomass in plankton in the region may be structured based on partitioned horizontal and vertical habitats and food resources. bacterioplankton phytoplankton zooplankton debris ecosystems micro (micro mesoplankton Rio State Brazil 2400 2 400 2,40 time visavis vis periods slope environment temperatures salinities waters resources 240 40 2,4 24 4 2,

Abstract Aberrantidae is a small group of polychaetes morphologically homogenous and rarely collected. Adult individuals usually have a few millimeters and about 40 chaetigers. Living specimens are transparent, yellowish-brown with a dark alimentary channel and have reddish eyes. The few records of Aberranta , the only described genus in the family, are from mud, sand, sandy-mud, and coarse sand, from four to 3,250 m. All known species have been recorded from the eastern USA, Mediterranean, and China. The examined material is from three projects coordinated by CENPES/Petrobras, the Brazilian oil company. Samples were collected from continental shelf, canyons, and slope depths. Polychaetes and others benthic organisms were sieved from the sediment, fixed in a 4% formalin solution, conserved in 70% alcohol, and then identified. The sampling was carried out from 25 to 3000 m depth, but individuals were collected from 383 to 1312 m. The new species, Aberranta magnunlanai sp. nov., is characterized by the absence of eyes, branchiae from chaetiger 3, and by having three types of neurochaetae: a) thick and smooth capillaries, b) capillary of intermediary length and with long marginal serration, and c) lyriform chaetae with spinose shaft and distal projections of same length. This is the first record of the genus in the southern hemisphere. 4 chaetigers transparent yellowishbrown yellowish brown eyes family mud sand sandymud, sandymud sandy sandy-mud 3250 3 250 3,25 USA Mediterranean China CENPESPetrobras CENPES Petrobras CENPES/Petrobras company shelf canyons depths sediment solution 70 alcohol identified 2 300 depth 38 131 sp nov nov. neurochaetae capillaries b serration c hemisphere 325 3,2 7 30 13 32 1

ABSTRACT In the northern portion of the Villarino district, in the southwest of the province of Buenos Aires, there is a continental dune chain. These sandy accumulations host a phreatic aquifer with waters of good physical and chemical quality, which is the main source of water supply for the populations of the area. The present work aims to determine the hydrodynamic characteristics of this aquifer, drawing a piezometric and isopaquic map of the unsaturated zone using specific software. With these maps we were able to identify the phreatic morphology, the direction of groundwater flow and its velocity, in addition to calculating the hydraulic gradients. As a result, it was possible to determine that the groundwater flow direction in the area broadly follows the slope of the terrain, with the highest piezometric levels tending to be located in the southeastern portion of the dune chain, while the lowest piezometric levels are located in the northwestern portion. The average hydraulic gradient is around 3 ‰, while the effective groundwater velocity averages 0,26 m/d. The greatest thicknesses of the unsaturated zone are recorded in the southeast of the chain, coinciding with the highest topographic elevations. In 90% of the area considered, it does not exceed 8 m. Knowledge of the phreatimetry and hydrodynamics of an aquifer provides fundamental information for understanding its functioning, which is necessary for the rational and sustainable management of water resources.

RESUMEN En la porción septentrional del partido de Villarino, sudoeste de la provincia de Buenos Aires, se encuentra un cordón medanoso continental. Estas acumulaciones arenosas alojan un acuífero freático con aguas de buena calidad fisicoquímica que es la principal fuente de abastecimiento de las poblaciones del área. El presente trabajo tiene como objetivo determinar las características hidrodinámicas de dicho acuífero, confeccionando un mapa piezométrico e isopáquico de la zona no saturada mediante el uso de software específico. Con estos mapas se logró identificar la morfología freática, la dirección de flujo del agua subterránea y su velocidad de movimiento, además de calcular los gradientes hidráulicos. Como resultado, se pudo definir que la dirección de flujo del agua subterránea en la zona sigue a grandes rasgos la inclinación del terreno, con los mayores niveles piezométricos tendientes a ubicarse en la porción sudeste del cordón de dunas, mientras que las cotas piezométricas más bajas se ubican en la porción noroeste. El gradiente hidráulico promedio se encuentra en torno al 3 ‰, mientras que la velocidad efectiva del agua subterránea tiene un promedio de 0,26 m/d. Los mayores espesores de la zona no saturada se registran en el sudeste de la cadena de dunas, coincidentes con las mayores cotas topográficas. En un 90% del área considerada, el mismo no supera los 8 m. El conocimiento de la freatimetría e hidrodinámica de un acuífero permite obtener información fundamental para la comprensión del funcionamiento del mismo, necesaria para la gestión racional y sustentable del recurso hídrico.

Resumen La presente investigación tiene como análisis de estudio el relieve de los municipios de Guaraciaba do Norte y Carnaubal, ambos situados en la meseta sedimentaria de Ibiapaba, en la porción noroeste del estado de Ceará. Esto puesto, se objetivó, mapear los compartimentos del relieve, indicando los modelados e índice de disección de los mismos utilizando escala de 1:300.000, con el fin de evidenciar el actual estado del relieve del área. En esta perspectiva, presenta aspectos de la cartografía geomorfológica, resaltando su importancia para los estudios de las geoformas y para la planificación ambiental. Adoptamos la propuesta teórica y metodológica de mapeo geomorfológico de Ross (1990) a partir del análisis taxonómico del relieve inspirado en las concepciones de morfoestructura y morfoescultura. Fueron mapeadas cuatro subunidades morfoesculturales con patrones de aplanamiento y denudación las cuales presentaron índice de disección del relieve variando entre débil a moderada, o sea, áreas de cierta forma en equilibrio incluso con cotas altimétricas y declividad con elevados valores. Se concluye la diversidad de formas de relieve las cuales reflejan en el escenario de los paisajes.

Resumo A presente pesquisa tem como análise de estudo o relevo dos municípios de Guaraciaba do Norte e Carnaubal, ambos situados no planalto sedimentar da Ibiapaba, na porção noroeste do estado do Ceará. Isto posto, objetivou-se mapear os compartimentos do relevo, indicando os modelados e índice de dissecação dos mesmos utilizando escala de 1:300.000, com o intuito de evidenciar o atual estado do relevo da área. Nesta perspectiva, apresenta aspectos da cartografia geomorfológica, ressaltando sua importância para os estudos das geoformas e para o planejamento ambiental. Adotamos a proposta teórica e metodológica de mapeamento geomorfológico de Ross (1990) a partir da análise taxonômica do relevo inspirada nas concepções de morfoestrutura e morfoescultura. Foram mapeadas quatro subunidades morfoesculturais com padrões de aplanamento e denudação as quais apresentaram índice de dissecação do relevo variando entre fraca a moderada, ou seja, áreas de certa forma em equilíbrio mesmo com cotas altimétricas e declividade com elevados valores. Conclui-se a diversidade de formas de relevo as quais refletem no cenário das paisagens.

Abstract This study analyzes the importance of the municipalities of Guaraciaba do Norte and Carnaúbal, both located in the sedimentary plateau of Ibiapaba, in the northwest portion of the state of Ceará. That being said, the objective was to map the relief compartments, indicating the models and the dissection index of them using a scale of 1:300,000, in order to highlight the current state of the relief of the area. In this perspective, it presents aspects of geomorphological cartography, emphasizing its importance for geoform studies and for environmental planning. We adopted the theoretical and methodological proposal of Ross’ geomorphological mapping (1990) based on the taxonomic analysis of the relief inspired by the conceptions of morphometry and morphological sculpture. Four morphological and sculptural subunits were mapped with flattening and denudation patterns, which presented dissection index of the relief varying between weak and moderate, that is, areas in some way in equilibrium even with elevation and slope with high values. It is concluded the diversity of forms of relief which reflect in the scenery of the landscapes.

Abstract Continental margins usually have a high degree of environmental heterogeneity, which, in turn, promotes high benthic biodiversity. The South-Southeast regions concentrate the most well-mapped areas of the Brazilian continental margin regarding seafloor geomorphology and physical oceanography. However, the structure of the soft-sediment benthic fauna of the continental slope is still unknown. Characterization and understanding of the Brazilian continental slope biota are imperative since human activities are increasing in the last decades, especially after the discovery of the pre-salt reservoir in Santos Basin. In this study, we aimed to establish a baseline of the spatial distribution of the benthic macrofaunal communities regarding their latitudinal and bathymetric patterns in the Santos Basin to support future environmental monitoring activities in the region. As part of the Santos Project – The Santos Basin Regional Environmental Characterization (PCR-BS) – coordinated by CENPES/PETROBRAS, a benthic oceanographic cruise was carried out in 2019. Sediment samples were collected using a GOMEX-type box corer in 47 stations distributed in eight transects (400– 2,400 m depth range). In total, 12 additional stations (1,300–2,200 m) were defined to cover an area where oil and gas are exploited. Our results showed that macrofaunal assemblages of the Santos Basin present strong depth zonation related to changes in organic matter input, as well as to temperature, carbonate, and grain size. At local scale, the northern sector stood out for having a higher abundance of macrofauna in the upper slope (400 m) and it probably reflects the oceanographic processes and the organic enrichment caused by the upwelling events that occur at Cabo Frio region. The zonation pattern and the dominance of some polychaete, peracarid crustacean, and bivalve families were similar to other SE Brazilian continental margins. heterogeneity which turn biodiversity SouthSoutheast South Southeast wellmapped mapped oceanography However softsediment soft sediment unknown decades presalt pre salt study region PCRBS PCR BS (PCR-BS CENPESPETROBRAS CENPES PETROBRAS CENPES/PETROBRAS 2019 GOMEXtype GOMEX type 4 400– 400 2400 2 2,40 range. range . range) total 1 1,300–2,200 13002200 300 200 (1,300–2,20 exploited input temperature carbonate size scale (40 polychaete crustacean 201 40 240 2,4 1,300–2,20 1300220 30 20 (1,300–2,2 (4 24 2, 1,300–2,2 130022 3 (1,300–2, ( 1,300–2, 13002 (1,300–2 1,300–2 1300 (1,300– 1,300– 130 (1,300 1,300 13 (1,30 1,30 (1,3 1,3 (1, 1, (1

Abstract The extensive coverage of 3-D seismic data on the Santos Basin deep water offered an integrated vision of the local physiography and medium- to small-scale geomorphological features, which enhances the understanding of its constructive/deconstructive natural processes and their interrelations. The Santos Basin is a divergent marginal basin composed of three main physiographic provinces: its continental shelf, continental slope, and the São Paulo Plateau, whose dimensions, orientation, gradients, and relief interact with oceanographic, biological, and geological processes. This study geologically contextualized environmental data related to the Regional Environmental Characterization Project of the Santos Basin (hereinafter referred to as PCR-BS), especially regarding the regional physiographical architecture and deep-water geomorphological provinces as a background for the benthic communities and the distribution of several of its geochemical parameters. The integrated analysis of 3-D seismic and multibeam bathymetric data and its derivatives (gradient and edge maps) — calibrated by 108 piston cores — aimed to evaluate its seafloor physiographic features and geological processes. Edge detection seismic attributes enhance gradient contrast, which, in turn, can map innumerous medium- to small-scale geomorphic features (features solved in maps at a 1:1,000,000 scale or larger), such as canyons, channels, ravines, pockmark units, pockmark fields, lineaments, carbonate and coral mounds, salt-related features (crests, minibasins, and crestal grabens), scars and rugous relief associated with mass-transport deposits, and bottom current-related features (depressions and furrows). The slope and the gently dipping plateau (São Paulo Plateau) that follow it eastward show four geomorphological domains based on their direction, profile, average gradient, shelf break isobath, distribution of its medium-small scale geomorphic features, and the presence or absence of evaporites at subsurface. The central-northern São Paulo Plateau contains salt-related topographic elevations (salt diapirs and walls) and depressions (minibasins) that give a rough aspect to the seafloor relief. 3D D 3 medium smallscale small constructivedeconstructive constructive deconstructive interrelations dimensions orientation gradients oceanographic biological hereinafter PCRBS, PCRBS PCR BS , PCR-BS) deepwater parameters 10 contrast turn 11,000,000 11000000 1 1,000,000 000 1:1,000,00 larger, larger larger) canyons channels ravines units fields lineaments mounds saltrelated salt crests, crests (crests minibasins grabens, grabens grabens) masstransport mass transport deposits currentrelated current furrows. furrows . furrows) direction profile isobath mediumsmall subsurface centralnorthern central northern walls (minibasins PCR-BS 11 11,000,00 1100000 1000000 1,000,00 00 1:1,000,0 11,000,0 110000 100000 1,000,0 0 1:1,000, 11,000, 11000 10000 1,000, 1:1,000 11,000 1100 1000 1,000 1:1,00 11,00 110 100 1,00 1:1,0 11,0 1,0 1:1, 11, 1, 1:1 1:

ABSTRACT The ocean bottom morphology, depth, sediment grain size, sediment sorting, carbonate content, and water depth are used to compose seafloor maps as support for biological studies. Sediments are reworked by waves and currents and accumulate according to the hydrodynamic level on the continental shelf. In contrast, sediments are accumulated by pelagic settling, mass wasting, turbidity flows, and boundary currents on the slope. Sea level oscillations during the Quaternary also played an important role in modifying the shelf seabed's morphology and sedimentary mosaic composition. The work addresses these topics in the Santos Basin based on extensive bathymetric data, shallow seismic records, and stratified bottom sediment samples in water depths ranging from 25 to 2,400m, as part of The Santos Basin Regional Environmental Characterization Project (PCR-BS). The main objective is to provide broad background information on the sedimentology and morphology of Santos Basin, focusing on the continental shelf. The morphology, sediment supply, shelf orientation, and ocean climate imprint the Santos Basin's characteristics. The Northern shelf sector is the most dynamic because of the narrow shelf, steep gradient, and East-West shoreline orientation, providing conditions for storm waves to approach and mobilize sediment in the ocean bottom shallow than 50 m water depth. The Southern sector of the shelf is much broader than the Northern sector; it displays a gentler gradient, and its orientation is Northeast-Southwest; therefore, less subject to storm waves than the Northern sector. size sorting content studies contrast settling wasting flows slope seabeds seabed s composition data records 2 2400m 400m 2,400m PCRBS. PCRBS PCR BS . (PCR-BS) supply Basins characteristics gradient EastWest East West 5 NortheastSouthwest Northeast Southwest Northeast-Southwest therefore (PCR-BS

METALS IN SEDIMENTS FROM THE SHELF-SLOPE INTERFACE OFF THE POTIGUAR BASIN OFFSHORE OIL EXPLORATION AREA, NE BRAZIL. Marine sediments collected in November 2009 and July 2011 at depths ranging from 150 m to 2,000 m in the Potiguar Basin, northeastern Brazil, were analyzed for their main sedimentological characteristics (contents of carbon, nitrogen and their stable isotopes) and metals (Al, Fe, Mn, As, Cr, Cu, Ni, Pb, V and Zn) concentrations and their spatial distribution. Sediments were relatively rich in organic matter (C-org: 0.21% to 0.56%) and metals concentrations increased with depth, suggesting an accumulation of fine and terrigenous sediments eroded and transported from the continental shelf to the slope region. Metals concentrations were higher than those observed in coarser shelf sediments, because of sorting of fine-grained sediments. Iron (Fe), Cr and Cu distribution, although presenting this general pattern, also suggests some changes along the transport. Fe and Cr, probably in discrete minerals, are less affected by accumulation in deeper sediments. The high enrichment in Cu, however, suggests additional sources directly to slope sediments, probably by biological productivity and deposition through the water column. The concentrations of all metals are lower or fall close to the lowest range of concentrations reported for slope sediments from other marine regions worldwide and no evidence of anthropogenic contribution was evident. SHELFSLOPE SHELF SLOPE AREA BRAZIL 200 201 15 2000 2 000 2,00 Basin Brazil contents carbon isotopes Al, Al (Al Mn As Ni Pb Zn distribution Corg C org (C-org 021 0 21 0.21 0.56% 056 56 depth region finegrained grained , (Fe) pattern transport minerals however column evident 20 1 00 2,0 02 0.2 0.56 05 5 (Fe 2, 0. 0.5

Abstract This study aimed to characterize the spatial distribution and composition of living Benthic Foraminifera (BF) and to comprehend how environmental conditions (e.g., organic matter) can affect communities of these protozoa in the northern and southern sectors of the Santos Basin (SB), in the continental slope and São Paulo Plateau. In this context, 23 stations (65 samples including replicates at each station) were collected between 400 and 2,400 m water depth. Multivariate analyses revealed that the ecological structure of the community changes mainly along the bathymetric gradients. Stations located between 400 and 700 m, both in northern and southern sectors, are characterized by the presence of indicator species of high intensity of currents, such as Globocassidulina subglobosa and Trifarina bradyi. These stations are also mainly marked by the occurrence of Epistominella exigua, a phytodetritivore species. The stations at 1,000 and 1,300 m depth, in both sectors, are characterized by high accumulation of organic matter in the sediments, which favors the development of agglutinated foraminifera species, such as those of the genus Reophax. Finally, the lower slope and the São Paulo Plateau, in both sectors, are oligotrophic regions, with pulses of labile organic carbon, probably low current velocities and the presence of Alabaminella weddellensis. The quantity and quality of food, which are closely related to hydro-sedimentary dynamics and bentho-pelagic coupling in the slope and São Paulo Plateau, are the main factors that influence the distribution of living BF assemblages in the SB. (BF e.g., eg e g (e.g. SB, SB , (SB) Plateau context 2 65 (6 station 40 2400 2,40 depth gradients 70 currents bradyi exigua 1000 1 000 1,00 1300 300 1,30 sediments Reophax Finally regions carbon weddellensis food hydrosedimentary hydro sedimentary benthopelagic bentho pelagic e.g. (e.g (SB 6 ( 4 240 2,4 7 100 00 1,0 130 30 1,3 e.g 24 2, 10 0 1, 13 3

Abstract Five anomuran and one brachyuran species collected from continental shelf and slope off southern Brazil have their geographic ranges considerably extended southward: Neolithodes agassizii (Smith), Paguristes spectabilis McLaughlin and Provenzano, Pagurus heblingi Nucci and Melo, Phimochirus occlusus (Henderson), Mixtopagurus paradoxus A. Milne-Edwards, and the brachyuran Euchirograpsus antillensis Türkay. Pagurus heblingi was previously known only from its type locality (off Cabo Frio, Rio de Janeiro) and from off Espírito Santo. Paguristes spectabilis was known only from the holotype (off Trinidad, Caribbean Sea) and two additional females from off Rio de Janeiro. One female was found of the brachyuran Robertsella meridionalis Tavares and Gouvêa, a species previously known only from two males. Additionally, the occurrence of the hermit crabs Dardanus venosus (H. Milne Edwards) and Oncopagurus gracilis (Henderson), and the brachyuran Hexapanopeus paulensis Rathbun are confirmed for Santa Catarina. The record of the brachyuran Neopilumnoplax americana (Rathbun) from Santa Catarina (27°S) probably actually refers to Neopilumnoplax lipkeholthuisi Tavares and Melo, a species described from Rio Grande do Sul (33°S) and Mar del Plata (37°S). southward Smith, Smith , (Smith) Provenzano Melo Henderson, Henderson (Henderson) A MilneEdwards, MilneEdwards Edwards, Edwards Milne-Edwards Türkay Frio Janeiro Santo Trinidad Sea Gouvêa males Additionally H. H (H (Rathbun 27°S 27S S 27 (27°S 33°S 33S 33 (33°S 37°S. 37S 37°S . 37 (37°S) (Smith (Henderson 2 3 (37°S

Abstract This study aims model the distribution of meiofauna indicators in relation to environmental variables from the Santos Basin continental margin, SE Brazil, using machine learning techniques, to provide baseline information and foster future monitoring programs. A total of 100 sampling stations were distributed in eight transects and 11 isobaths (25 to 2,400 m) perpendicular to the coast. In each station, three replicates were sampled for meiofauna and 38 environmental parameters. A total of 28 meiofauna taxa were found, with a mean richness varying from 3 to 15 taxa per station. Meiofauna mean density varied between 55 and 2,001 ind. 10 cm-2. Density of meiofauna and its most frequent taxa (Nematoda, Copepoda, Kinorhyncha, and Polychaeta), and taxa richness were used as descriptors for the models. Meiofauna and nematode density showed the highest training and testing accuracies, with R² values above 0.74. Based on the distribution of meiofauna descriptors and their responses to environmental conditions, we suggest a mosaic of six benthic zones. The La Plata Plume zone and the Cabo Frio Upwelling zone are two of the most diverse and productive zones in the continental shelf, wich are separated by the less productive Central Continental Shelf zone. A fourth zone, with very low meiofauna densities, corresponds to the carbonated sediments of the shelf-break. The Upper and Mid-Slope is a narrow zone along the entire basin, with intermediate densities and small amounts of high-quality organic carbon. The largest, impoverished zone, the Lower Slope and Plateau comprises the deepest areas and the São Paulo Plateau. The study showed that, although some zones can be recognized by most meiofauna descriptors, others are better characterized by specific ones, implying that meiofauna indicators should be monitored concomitantly. We recommend the optimization of sampling design based on our model to reduce costs and increase our understanding of the system. margin Brazil techniques programs 1 25 (2 2400 2 400 2,40 m coast station parameters found 5 2001 001 2,00 ind cm2. cm2 cm 2. cm-2 Nematoda, Nematoda (Nematoda Copepoda Kinorhyncha Polychaeta, Polychaeta , Polychaeta) models accuracies R 074 0 74 0.74 conditions shelf shelfbreak. shelfbreak break. break shelf-break MidSlope Mid basin highquality high quality carbon largest ones concomitantly system ( 240 40 2,4 200 00 2,0 cm- 07 7 0.7 24 4 2, 20 0.

Abstract This work describes the circulation over the continental slope and the São Paulo Plateau in the Santos Basin during the SANSED winter 2019 survey. The cruise consisted of four legs in the period between June, 11 and August, 03 2019. The observed circulation is dominated by the Atlantic southwestern boundary current regime and remotely-generated anticyclones and cyclones. The former is composed by the Brazil Current, the Intermediate Western Boundary Current and their mesoscale meanders; the latter are 300km vortical rings with origin in the eastern side of the South Atlantic Basin. A Lagrangian scheme applied over satellite altimeter maps indicate that the origin of these rings is primarily the Cape Basin of South Africa. The interaction between the boundary currents, their cyclonic meanders, and the anticyclonic rings is complex, and varies widely. During the SANSED winter 2019 survey period, three anticyclones interacted with the Brazil Current, instabilizing it, forming dipoles with the current cyclonic meanders, leading to their downstream propagation. Ancienter cyclonic eddies within Santos Basin may interfere with the propagation of the large anticyclones further south. In addition, the continuous arrival of remotely-originated anticyclones, the larger portion over the São Paulo Plateau presented a tendency of counter-clockwise circulation during the whole cruise period.

Abstract There are records of seven species of hagfishes in the Argentine shelf and continental slope, comprising the most diverse region for this group in the Southwestern Atlantic. Here, the authors report the occurrence of Myxine affinis and Myxine knappi in San Jorge gulf, adding two species to the ichthyofauna of central Patagonia. A specimen of M. affinis (447 mm TL; hermaphrodite) was incidentally caught by the Patagonian shrimp fishing fleet and collected by the Fishery Observer Program of Fisheries Secretariat of the Chubut Province, Argentina. Subsequently, the authors collected a second specimen of M. affinis (358 mm TL; female) and a specimen of M. knappi (303 mm TL) during the research cruises of the oceanographic vessel ARA Puerto Deseado, within the “Pampa Azul” initiative. The latter is the twelfth record for the species. These specimens are stored in the ichthy ological collection of the Instituto de Investigación de Hidrobiología of the Universidad Nacional de la Patagonia San Juan Bosco, Trelew (UNPSJB-ICT), Argentina. These new records of M. affinis and M. knappi extended their known distribution by 850 km and 220 km northward, respectively. In addition, the authors reported morphomet ric, meristic and reproductive variables of the collected specimens.

Resumen En aguas de la plataforma Argentina y del talud continental se tiene registro de siete especies de mixines (hagfishes), comprendiendo la región de mayor diversidad del Atlántico sudoccidental. A partir del Programa de Observadores a Bordo de la Secretaría de Pesca de la Provincia del Chubut, que monitorea las pesquerías industriales de la región, se capturó incidentalmente un ejemplar de Myxine affinis (447 mm TL; hermafrodita). Posteriormente, durante las campa ñas de investigación del buque oceanográfico ARA Puerto Deseado, en el marco de la iniciativa “Pampa Azul”, se registró un segundo ejemplar de M. affinis (358 mm TL; hembra) y un ejemplar de Myxine knappi de 303 mm TL. Este último es el doceavo registro para la especie. Todos los ejemplares fueron capturados mediante la utilización de redes de arrastre de fondo y se encuentran depositados en la colección ictiológica del Instituto de Investigación de Hidrobiología de la Universidad Nacional de la Patagonia San Juan Bosco, sede Trelew (UNPSJB-ICT), Argentina. Estos nuevos registros amplían la distribución conocida para M. affinis y M. knappi en 850 km y 220 km respectivamente, sumando así dos especies a la ictiofauna de Patagonia central. En los ejemplares colectados, se registraron variables morfométricas, merísticas y reproductivas.

ABSTRACT. This note analyzes for the first time the geomorphology and sedimentary features of the Simpson Submarine Canyon (SSC), located between Chiloé Island and the Taitao Peninsula. For that purpose, multibeam bathymetric data were obtained in 2018. The SSC has a unique orientation compared to most canyons on the Chilean margin. Slope escarpments, topographic irregularities, and sinuosity of the canyon could be associated with regional tectonics. Sediment transport and deposition along the axis define the transversal morphology. On the canyon walls, erosion and transport processes dominate, evidenced by gullies, channels, and mass removals, which leave debris on the axis. We report a large landslide from a canyon wall, which could be due to a high-energy event such as an earthquake; and the generation of a large sediment wave field outside the canyon mouth, indicating a great activity by sedimentary processes. All the above could indicate that the canyon is continuously evolving.

ABSTRACT An autonomous lander equipped with a video camera (dropcam) was used for in situ observations of the bento-demersal macrofauna on the upper continental slope off Punta Pichalo in northern Chile, an area of permanent coastal upwelling processes, located ~70 km north of Iquique. The lander was deployed at nine stations and between 227 and 798 m of depth. According to morphological characteristics, 34 operational taxonomic units (OTUs) were identified to the lowest taxonomic level; 24 belonged to macroinvertebrates and 10 to fishes. Macroinvertebrates comprised 9 OTUs of crustaceans, seven cnidarians, and six echinoderms. Fishes included 3 OTUs of the order Chondrichthyes, 3 belonging to macrourid. Perciformes, Anguilliformes, and Alepocephaliformes were represented by one OTU each. Also, we observed one species of lanternfish (Myctophidae). Apart from the brachyuran decapod Lophorochinia parabranchia Garth, 1969 and euphausiids, all species were observed at depths greater than 560 m. The presence of one individual identified as the granulate dogfish Centroscyllium granulatum Günther, 1887 extended the known distribution range of this species about 1000 km to the north. Images taken at 795 m showed Bathyraja peruana McEachran & Miyake, 1984. Our study suggests that the upper continental slope of northern Chile harbors nearly undiscovered biodiversity, worth to be studied more intensively to complete the comparable sparse knowledge about marine biodiversity and species distribution at the continental margin in front of Chile.