scholarly journals Extended Pelagic Life in a Bathybenthic Octopus

2020 ◽  
Vol 7 ◽  
Author(s):  
Roger Villanueva ◽  
Vladimir V. Laptikhovsky ◽  
Stuart B. Piertney ◽  
Fernando Ángel Fernández-Álvarez ◽  
Martin A. Collins ◽  
...  
Keyword(s):  
North Atlantic ◽  
Morphological Characteristics ◽  
The South ◽  
Large Size ◽  
Pelagic Environment

Planktonic stages of benthic octopuses can reach relatively large sizes in some species, usually in oceanic, epipelagic waters while living as part of the macroplankton. These young octopuses appear to delay settlement on the seabed for an undetermined period of time that is probably longer than for those octopus paralarvae living in coastal, neritic waters. The reason for this delay is unknown and existing information about their biology is very scarce. Here we report on the presence of juvenile and subadult forms of the bathybenthic octopus Pteroctopus tetracirrhus in oceanic waters of the South and North Atlantic and its association with the pyrosomid species Pyrosoma atlanticum, apparently used by the octopus as a refuge or shelter. The relatively large size of the P. tetracirrhus living in oceanic waters as the individuals reported here, together with the morphological characteristics of this bathybenthic species including its gelatinous body, minute suckers embedded in swollen skin and the deep interbrachial web, indicates that P. tetracirrhus may be considered a model of a transitional octopus species that is colonizing the pelagic environment by avoiding descending to the bathyal benthos. This process seems to occur in the same way as in the supposed origin of the ctenoglossan holopelagic octopods of the families Amphitretidae, Bolitaenidae, and Vitreledonellidae, which have arisen via neoteny from the planktonic paralarval stages of benthic octopuses.

scholarly journals Phylogenetic relationships of the South American Doradoidea (Ostariophysi: Siluriformes)

2014 ◽  
Vol 12 (3) ◽  
pp. 451-564 ◽  
Author(s):  
José L. O. Birindelli
Keyword(s):  
Phylogenetic Analysis ◽  
New Genus ◽  
Morphological Characteristics ◽  
Morphological Characters ◽  
The Other ◽  
Phylogenetic Position ◽  
South American ◽  
Parsimony Analysis ◽  
The South ◽  
Large Size

A phylogenetic analysis based on 311 morphological characters is presented for most species of the Doradidae, all genera of the Auchenipteridae, and representatives of 16 other catfish families. The hypothesis that was derived from the six most parsimonious trees support the monophyly of the South American Doradoidea (Doradidae plus Auchenipteridae), as well as the monophyly of the clade Doradoidea plus the African Mochokidae. In addition, the clade with Sisoroidea plus Aspredinidae was considered sister to Doradoidea plus Mochokidae. Within the Auchenipteridae, the results support the monophyly of the Centromochlinae and Auchenipterinae. The latter is composed of Tocantinsia, and four monophyletic units, two small with Asterophysusand Liosomadoras, and Pseudotatiaand Pseudauchenipterus, respectively, and two large ones with the remaining genera. Within the Doradidae, parsimony analysis recovered Wertheimeriaas sister to Kalyptodoras, composing a clade sister to all remaining doradids, which include Franciscodorasand two monophyletic groups: Astrodoradinae (plus Acanthodorasand Agamyxis) and Doradinae (new arrangement). Wertheimerinae, new subfamily, is described for Kalyptodoras and Wertheimeria. Doradinae is corroborated as monophyletic and composed of four groups, one including Centrochirand Platydoras, the other with the large-size species of doradids (except Oxydoras), another with Orinocodoras, Rhinodoras, and Rhynchodoras, and another with Oxydorasplus all the fimbriate-barbel doradids. Based on the results, the species of Opsodoras are included in Hemidoras; and Tenellus, new genus, is described to include Nemadoras trimaculatus, N. leporhinusand Nemadoras ternetzi. Due to conflicting hypotheses of the phylogenetic position of Acanthodoras, Agamyxis, and Franciscodoras, these are considered as incertae sedisin Doradidae. All suprageneric taxa of the Doradoidea are diagnosed based on synapomorphic morphological characteristics.

Leptochelia Vatulelensis (Crustacea: Tanaidacea), A New Species From Anchialine Caves of the South-Western Pacific

2011 ◽  
Vol 54 (2) ◽  
pp. 351-363
Author(s):  
Modest Guţu ◽  
Thomas Iliffe
Keyword(s):  
New Species ◽  
New Caledonia ◽  
Morphological Characteristics ◽  
Morphological Features ◽  
Western Pacific ◽  
Small Islands ◽  
The South ◽  
Anchialine Caves ◽  
A New Species

Leptochelia Vatulelensis(Crustacea: Tanaidacea), A New Species From Anchialine Caves of the South-Western PacificLeptochelia vatulelensisn. sp., discovered on the small islands of Vatulele (Fijian group) and Ouvéa (Loyalty Islands, New Caledonia), is described and illustrated. The new species is distinguished from the others of the"Leptochelia-dubiagroup" (to which it is generally similar) by the following combination of morphological characteristics: (1) the presence of three to four distal setae on the maxilliped basis; (2) merus of pereopods III and IV with only a distosternal seta; (3) endopod of the uropods formed of four (rarely three) articles; (4) males with two (sometimes three) relatively short aesthetascs on the first five articles of the antennular flagellum; (5) male cheliped with a diminished dimorphism; (6) males with a vertical comb-row of setae on the cheliped propodus. Although it inhabits inland, anchialine caves, the new species lacks morphological features that are characteristic of some cave species.

Observed seasonal regimes of North-South Atlantic Ocean interbasin exchange

2019 ◽  
Author(s):  
Hamed D. Ibrahim
Keyword(s):  
North Atlantic ◽  
Climate Models ◽  
South Atlantic ◽  
Meridional Overturning Circulation ◽  
Volume Flux ◽  
The South ◽  
The North ◽  
Basin Scale ◽  
Interbasin Exchange ◽  
North And South

North and South Atlantic lateral volume exchange is a key component of the Atlantic Meridional Overturning Circulation (AMOC) embedded in Earth’s climate. Northward AMOC heat transport within this exchange mitigates the large heat loss to the atmosphere in the northern North Atlantic. Because of inadequate climate data, observational basin-scale studies of net interbasin exchange between the North and South Atlantic have been limited. Here ten independent climate datasets, five satellite-derived and five analyses, are synthesized to show that North and South Atlantic climatological net lateral volume exchange is partitioned into two seasonal regimes. From late-May to late-November, net lateral volume flux is from the North to the South Atlantic; whereas from late-November to late-May, net lateral volume flux is from the South to the North Atlantic. This climatological characterization offers a framework for assessing seasonal variations in these basins and provides a constraint for climate models that simulate AMOC dynamics.

scholarly journals Influence of the North Atlantic oscillation on the atmospheric levels of benzo[a]pyrene over Europe

2021 ◽  
Author(s):  
Pedro Jiménez-Guerrero ◽  
Nuno Ratola
Keyword(s):  
Spatial Pattern ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Transport Model ◽  
Regional Scale ◽  
The South ◽  
Climatic Fluctuations ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

AbstractThe atmospheric concentration of persistent organic pollutants (and of polycyclic aromatic hydrocarbons, PAHs, in particular) is closely related to climate change and climatic fluctuations, which are likely to influence contaminant’s transport pathways and transfer processes. Predicting how climate variability alters PAHs concentrations in the atmosphere still poses an exceptional challenge. In this sense, the main objective of this contribution is to assess the relationship between the North Atlantic Oscillation (NAO) index and the mean concentration of benzo[a]pyrene (BaP, the most studied PAH congener) in a domain covering Europe, with an emphasis on the effect of regional-scale processes. A numerical simulation for a present climate period of 30 years was performed using a regional chemistry transport model with a 25 km spatial resolution (horizontal), higher than those commonly applied. The results show an important seasonal behaviour, with a remarkable spatial pattern of difference between the north and the south of the domain. In winter, higher BaP ground levels are found during the NAO+ phase for the Mediterranean basin, while the spatial pattern of this feature (higher BaP levels during NAO+ phases) moves northwards in summer. These results show deviations up to and sometimes over 100% in the BaP mean concentrations, but statistically significant signals (p<0.1) of lower changes (20–40% variations in the signal) are found for the north of the domain in winter and for the south in summer.

scholarly journals A southern North Sea Miocene dinoflagellate cyst zonation

2004 ◽  
Vol 83 (4) ◽  
pp. 267-285 ◽  
Author(s):  
D.K. Munsterman ◽  
H. Brinkhuis
Keyword(s):  
The Netherlands ◽  
North Sea ◽  
North Atlantic ◽  
The South ◽  
Dinoflagellate Cyst ◽  
South Eastern ◽  
Southern North Sea ◽  
Age Model

AbstractAn integrated stratigraphical analysis emphasizing organic-walled dinoflagellate cyst (dinocyst) distribution has been carried out on multiple boreholes penetrating the Miocene in the subsurface of the Netherlands (southern North Sea Basin). The bulk of the investigated successions is attributed to the Breda Formation, a regional lithostatigraphical unit most complete in the south-eastern part of the Netherlands. In concert with a first regional integrated bio (chrono) sequence-stratigraphical framework, fourteen informal dinocyst zones for the southern North Sea Miocene (SNSM), and three subzones are proposed for the Breda Formation. By also integrating (chrono)stratigraphic information from Mediterranean and North Atlantic dinocyst studies a first ever detailed age-model is here proposed for the Miocene in the subsurface of the Netherlands.

Discordance Mapping of Argyre Basin: An Insight into the Fluvial and Subglacial Origin of Valley Networks in the Argyre Basin Region

2021 ◽  
Author(s):  
Rickbir Bahia ◽  
Anna Galofre ◽  
Stephen Covey-Crump ◽  
Merren Jones ◽  
Neil Mitchell
Keyword(s):  
Ice Sheet ◽  
Morphological Characteristics ◽  
Drainage Density ◽  
Recent Analysis ◽  
Surface Slope ◽  
The South ◽  
Total Length ◽  
Topographic Slope ◽  
Valley Networks ◽  
Slope Direction

&lt;p&gt;&lt;strong&gt;Introduction:&lt;/strong&gt;&amp;#160; Martian valley networks are evidence for surface run-off and past water cycles on ancient Mars. Many of the networks resemble terrestrial precipitation-fed systems; however, recent analysis has found that the geometries and morphological characteristics of some valley networks are more comparable to subglacial valley formation. Subglacial valleys have morphological characteristics that make them distinct from fluvial valley systems (i.e., those formed via precipitation or sapping erosion). Unlike fluvial valley networks, which follow the surface slope of the underlying topography, sub-glacial networks are orientated in the direction of the surface slope of the overlying ice-sheet. Therefore, subglacial valleys may have orientations that are discordant with the underlying topography. Discordance analysis, a technique that compares the valley paleoslope direction and topographic slope direction, has been applied to Mars to determine areas that have undergone topographic modification since valley formation. This technique could also be a tool for identify valleys with potential sub-glacial origins.&lt;/p&gt;&lt;p&gt;In this study, we mapped and applied discordance analysis to valley networks in and around Argyre basin. Detailed analysis was performed on four valley networks on eastern Argyre, to determine whether their characteristics are indicative of a fluvial or sub-glacial origin.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results:&lt;/strong&gt; 2669 V-Shaped valleys (total length = 36155.5 km) and 45 U-Shaped valleys (total length = 2683.5 km) were identified. Most V-Shaped valleys dissect the eastern and northern rim of Argyre Basin, with fewer in the south and west. The densest northern valley networks have values up to 0.098 km&lt;sup&gt;-1&lt;/sup&gt;, compared to the densest in the south with values of only 0.040 km&lt;sup&gt;-1&lt;/sup&gt;. U-Shaped valleys are prominent along the south/south-west rim, but are lacking along the northern rim of Argyre.&lt;/p&gt;&lt;p&gt;Most valleys (47.8 %) are concordant (&lt; 45&amp;#176; discordance) with present slope direction. Two dense groups of discordant valleys are present adjacent to Hale Crater and Nia Vallis. These areas display features associated with the presence of an ice-sheet/glacier &amp;#8211; e.g., glacial moraines and eskers. Additionally, the morphology of these valley systems are consistent with a subglacial origin.&lt;/p&gt;&lt;p&gt;Fento Vallis and the Darwin Crater valley system are concordant with present topographic slope, and are in close proximity to one another; however, their morphologies differ greatly. Fento Vallis consists of 25 valleys (total valley length of ~ 690 km) and drainage density of 0.019 km&lt;sup&gt;-1&lt;/sup&gt;. The Darwin Crater valley network consists of 49 valleys (total valley length of ~ 1351 km) and drainage density of 0.048 km&lt;sup&gt;-1&lt;/sup&gt;. Fento Vallis displays features (e.g., inner channel eskers) indicative of a subglacial origin. Alternatively, the Darwin Crater System has a planform associated with fluvial activity and originates from cirque like depressions. Although the Darwin Crater system appears to have a fluvial origin, less than 100 km to the east is Pallacopas Vallis, which displays inner eskers indicating that it has a subglacial origin.&lt;/p&gt;&lt;p&gt;Three of the networks analysed, which are &gt; 1000 km apart from one another, are likely subglacial in origin. Their occurrence indicates that an ice-sheet or multiple ice-sheets were present along the eastern region of Argyre throughout its history.&lt;/p&gt;

scholarly journals Location Matters! Exploring Brownfields Regeneration in a Spatial Context (A Case Study of the South Moravian Region, Czech Republic)

2013 ◽  
Vol 21 (2) ◽  
pp. 5-19 ◽  
Author(s):  
Bohumil Frantál ◽  
Josef Kunc ◽  
Eva Nováková ◽  
Petr Klusáček ◽  
Stanislav Martinát ◽  
...  
Keyword(s):  
Czech Republic ◽  
Local Development ◽  
The South ◽  
Development Potential ◽  
Large Size ◽  
Specific Factors ◽  
Functional Distribution ◽  
Using Data

Abstract In this paper the authors attempt to answer the question of which location and site-specific factors have a decisive influence on the successful regeneration of brownfields. Using data from the South Moravian Region (Czech Republic), we analyze the spatial and functional distribution of brownfields, and test the correlation between the development potential of municipalities and the distribution of the brownfields that have already been regenerated. We then compare the structure and characteristics of existing and regenerated brownfields to identify significant drivers and barriers in the regeneration process. The findings indicate that regenerated brownfields are more likely located in municipalities with a higher local development potential (represented by the rate of local business activities, spatial peripherality - proximity to the regional centre and the main road network, and the quality of local infrastructure). It is also demonstrated that the large size of brownfields, their previous industrial use and the existence of contamination are not determinative barriers for regeneration if the brownfields are located in attractive areas and their ownership relations are not complicated.

A new record of the copepod Xanthocalanus agilis Giesbrecht, 1893 (Calanoida, Phaennidae) from the South China Sea

Crustaceana ◽  
2019 ◽  
Vol 92 (7) ◽  
pp. 789-797
Author(s):  
Y. Z. Feng ◽  
Z. S. Liu
Keyword(s):  
South China Sea ◽  
South China ◽  
World Ocean ◽  
Morphological Characteristics ◽  
Distal Segment ◽  
The South China Sea ◽  
The South ◽  
China Sea ◽  
Deep Waters ◽  
The World

Abstract The genus Xanthocalanus inhabits the intermediate and deep waters of the world ocean. The present study records and describes the first female individual of Xanthocalanus agilis Giesbrecht, 1893, collected in the South China Sea (13°0.21′N 113°0.21′E) at depths of 500-800 m. This species was identified by the following morphological characteristics: (i) rostrum with 2 slender filaments; (ii) posterolateral corners of fifth thoracic somite protuberant and triangular, reaching the posterior margin of genital somite; (iii) first segment of fifth pereiopod (P5) with a list of inner marginal spinules, distal segment short with 3 robust terminal spines. This finding expands the known global and vertical distribution of X. agilis.

scholarly journals Stalked crinoids (Echinodermata) collected by the R/V Polarstern and Meteor in the south Atlantic and in Antarctica

Zootaxa ◽  
2012 ◽  
Vol 3425 (1) ◽  
pp. 1 ◽  
Author(s):  
MARC ELÉAUME ◽  
JENS-MICHAEL BOHN ◽  
MICHEL ROUX ◽  
NADIA AMÉZIANE
Keyword(s):  
North Atlantic ◽  
Deep Sea ◽  
South Atlantic ◽  
The South ◽  
The West ◽  
Walvis Ridge ◽  
The North ◽  
West Antarctic ◽  
Stalked Crinoids ◽  
Hard Substrates

During the last decades, R/V Meteor and R/V Polarstern deep-sea investigations in the south Atlantic and neighbouringSouthern Ocean collected new samples of stalked crinoids belonging to the families Bathycrinidae, Phrynocrinidae andHyocrinidae which are herein described. The species found are Bathycrinus australis A.H. Clark, 1907b (the most abun-dant), Dumetocrinus aff. antarcticus (Bather, 1908), Hyocrinus bethellianus Thomson, 1876, Feracrinus heinzelleri newspecies, and Porphyrocrinus cf. incrassatus (Gislén, 1933). As only stalk fragments of bathycrinids were frequently col-lected, a distinction between the two Atlantic species B. australis and B. aldrichianus is proposed using characters of co-lumnal articulations. A few specimens attributed to Porphyrocrinus cf. incrassatus, Hyocrinus bethellianus and Hyocrinussp. collected by the N/O Jean Charcot on the Walvis Ridge are also described, plus a new specimen of Porphyrocrinusincrassatus collected in the central mid-Atlantic. Biogeography and close affinities between species in the genera Bathy-crinus and Porphyrocrinus suggest an Antarctic origin of some stalked crinoids among the north Atlantic deep-sea fauna.The presence of B. australis in both the Angola and Cape basins suggests that the Walvis Ridge is not a bio-geographicalbarrier for this relatively eurybathic species, which can attach to hard substrates as well as anchor in sediment. The genusDumetocrinus seems to be an example of colonization of the west Antarctic platform from deeper environment where its ancestor lived.

First record of a rare copepod Lucicutia hulsemannae Markhaseva & Ferrari, 2005 (Calanoida, Lucicutiidae) for the South China Sea

Crustaceana ◽  
2019 ◽  
Vol 92 (10) ◽  
pp. 1249-1256
Author(s):  
Y. Z. Feng ◽  
Z. S. Liu
Keyword(s):  
South China Sea ◽  
South China ◽  
Morphological Characteristics ◽  
First Record ◽  
Lateral View ◽  
The South China Sea ◽  
The South ◽  
China Sea ◽  
Chinese Waters ◽  
Marginal Seta

Abstract The calanoid copepod Lucicutia hulsemannae Markhaseva & Ferrari, 2005 has, until now, only been recorded from the eastern tropical Pacific Ocean, i.e., in its description as a new species. The present study now reports L. hulsemannae for the first time from the southern basin of the South China Sea (7°59.57′N 113°0.1′E), at depths of 500-800 m. The main morphological characteristics of females of this species are: (i) Cephalosome with a pair of strong, triangular, lateral protrusions; (ii) plug of genital double-somite conical in lateral view, with swollen base; (iii) second urosomal somite significantly wider and shorter than third; (iv) inner marginal seta of second exopodal segment of fifth pereiopod (P5) thin towards its tip. This finding considerably expands the reported global distribution of L. hulsemannae, at the same time updating the checklist of copepods for Chinese waters.

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