scholarly journals A second peirosaurid crocodyliform from the Mid-Cretaceous Kem Kem Group of Morocco and the diversity of Gondwanan notosuchians outside South America

2021 ◽  
Vol 8 (10) ◽  
Author(s):  
Cecily S. C. Nicholl ◽  
Eloise S. E. Hunt ◽  
Driss Ouarhache ◽  
Philip D. Mannion
Keyword(s):  
South America ◽  
Late Cretaceous ◽  
North Africa ◽  
Lateral Surface ◽  
Middle Jurassic ◽  
Tooth Enamel ◽  
Phylogenetic Analyses ◽  
Late Eocene ◽  
South American ◽  
Early Late

Notosuchians are an extinct clade of terrestrial crocodyliforms with a particularly rich record in the late Early to Late Cretaceous (approx. 130–66 Ma) of Gondwana. Although much of this diversity comes from South America, Africa and Indo-Madagascar have also yielded numerous notosuchian remains. Three notosuchian species are currently recognized from the early Late Cretaceous (approx. 100 Ma) Kem Kem Group of Morocco, including the peirosaurid Hamadasuchus rebouli . Here, we describe two new specimens that demonstrate the presence of at least a fourth notosuchian species in this fauna. Antaeusuchus taouzensis n. gen. n. sp. is incorporated into one of the largest notosuchian-focused character-taxon matrices yet to be compiled, comprising 443 characters scored for 63 notosuchian species, with an increased sampling of African and peirosaurid species. Parsimony analyses run under equal and extended implied weighting consistently recover Antaeusuchus as a peirosaurid notosuchian, supported by the presence of two distinct waves on the dorsal dentary surface, a surangular which laterally overlaps the dentary above the mandibular fenestra, and a relatively broad mandibular symphysis. Within Peirosauridae, Antaeusuchus is recovered as the sister taxon of Hamadasuchus . However, it differs from Hamadasuchus with respect to several features, including the ornamentation of the lateral surface of the mandible, the angle of divergence of the mandibular rami, the texture of tooth enamel and the shape of the teeth, supporting their generic distinction. We present a critical reappraisal of the non-South American Gondwanan notosuchian record, which spans the Middle Jurassic–late Eocene. This review, as well as our phylogenetic analyses, indicate the existence of at least three approximately contemporaneous peirosaurid lineages within the Kem Kem Group, alongside other notosuchians, and support the peirosaurid affinities of the ‘trematochampsid’ Miadanasuchus oblita from the Maastrichtian of Madagascar. Furthermore, the Cretaceous record demonstrates the presence of multiple lineages of approximately contemporaneous notosuchians in several African and Madagascan faunas, and supports previous suggestions regarding an undocumented pre-Aptian radiation of Notosuchia. By contrast, the post-Cretaceous record is depauperate, comprising rare occurrences of sebecosuchians in north Africa prior to their extirpation.

Radiolarian assemblages of Middle and Late Jurassic to early Late Cretaceous (Cenomanian) ages from an olistolith record pelagic deposition within the Bornova Flysch Zone in western Turkey

2012 ◽  
Vol 183 (4) ◽  
pp. 307-318 ◽  
Author(s):  
Ugur Kagan Tekin ◽  
M. Cemal Göncüoglu ◽  
Seda Uzuncimen
Keyword(s):  
Late Cretaceous ◽  
Middle Jurassic ◽  
Late Jurassic ◽  
Western Turkey ◽  
Oceanic Basin ◽  
Platform Margin ◽  
Lowermost Part ◽  
Early Late ◽  
Radiolarian Assemblages

Abstract The Bornova Flysch Zone (BFZ) in NW Anatolia comprises several olistoliths or tectonic slivers, representing various parts of the Izmir-Ankara ocean. Radiolarian assemblages extracted from one of the olistoliths of the BFZ, cropping out along the Sögütlü section, to the NE Manisa city, were studied in detail. The lowermost part of the section contains latest Bajocian – early Callovian radiolarian taxa, followed by radiolarian assemblages indicating Late Jurassic to early Late Cretaceous (Cenomanian) ages. Previous studies reveal that the Izmir-Ankara oceanic basin was initially opened during late Ladinian – early Carnian. The new radiolarian data obtained from this olistolith reveals that relatively condensed, and possibly more or less continuous, pelagic sedimentation took place during the late Middle Jurassic to early Late Cretaceous in a non-volcanic oceanic basin closer to the Tauride-Anatolide platform margin.

scholarly journals The youngest South American rhynchocephalian, a survivor of the K/Pg extinction

2014 ◽  
Vol 281 (1792) ◽  
pp. 20140811 ◽  
Author(s):  
Sebastián Apesteguía ◽  
Raúl O. Gómez ◽  
Guillermo W. Rougier
Keyword(s):  
Phylogenetic Analysis ◽  
New Species ◽  
New Zealand ◽  
South America ◽  
Late Cretaceous ◽  
South American ◽  
New Taxon ◽  
Northern Patagonia ◽  
Extinction Event ◽  
New Form

Rhynchocephalian lepidosaurs, though once widespread worldwide, are represented today only by the tuatara ( Sphenodon ) of New Zealand. After their apparent early Cretaceous extinction in Laurasia, they survived in southern continents. In South America, they are represented by different lineages of Late Cretaceous eupropalinal forms until their disappearance by the Cretaceous/Palaeogene (K/Pg) boundary. We describe here the only unambiguous Palaeogene rhynchocephalian from South America; this new taxon is a younger species of the otherwise Late Cretaceous genus Kawasphenodon . Phylogenetic analysis confirms the allocation of the genus to the clade Opisthodontia. The new form from the Palaeogene of Central Patagonia is much smaller than Kawasphenodon expectatus from the Late Cretaceous of Northern Patagonia. The new species shows that at least one group of rhynchocephalians not related to the extant Sphenodon survived in South America beyond the K/Pg extinction event. Furthermore, it adds to other trans-K/Pg ectotherm tetrapod taxa, suggesting that the end-Cretaceous extinction affected Patagonia more benignly than the Laurasian landmasses.

scholarly journals Phanerozoic Vertical Movements in Morocco

2020 ◽  
Author(s):  
Remi J.G. Charton
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
Middle Jurassic ◽  
Late Jurassic ◽  
Numerical Models ◽  
Vertical Movements ◽  
The Past ◽  
Basement Rocks ◽  
Exhumation Rates ◽  
Early Late

Our understanding of the Earth’s interior is limited by the access we have of its deep layers, while the knowledge we have of Earth’s evolution is restricted to harvested information from the present state of our planet. We therefore use proxies, physical and numerical models, and observations made on and from the surface of the Earth. The landscape results from a combination of processes operating at the surface and in the subsurface. Thus, if one knows how to read the landscape, one may unfold its geological evolution.In the past decade, numerous studies have documented km-scale upward and downward vertical movements in the continental rifted margins of the Atlantic Ocean and in their hinterlands. These movements, described as exhumation (upward) and subsidence (downward), have been labelled as “unpredicted” and/or “unexpected”. ‘Unpredicted’ because conceptual, physical, and numerical models that we dispose of for the evolution of continental margins do not generally account for these relatively recent observations. ‘Unexpected’ because the km-scale vertical movements occurred when our record of the geological history is insufficient to support them. As yet, the mechanisms responsible for the km-scale vertical movements remain enigmatic.One of the common techniques used by geoscientists to investigate the past kinematics of the continental crust is to couple ‘low-temperature thermochronology’ and ‘time-temperature modelling’. In Morocco alone, over twenty studies were conducted following this approach. The reason behind this abundance of studies and the related enthusiasm of researchers towards Moroccan geology is due to its puzzling landscapes and complex history. In this Thesis, we investigate unconstrained aspects of the km-scale vertical movements that occurred in Morocco and its surroundings (Canary Islands, Algeria, Mali, and Mauritania). The transition area between generally subsiding domains and mostly exhuming domains, yet poorly understood, is discussed via the evolution of a profile, running across the rifted continental margin (chapter 2). Low-temperature thermochronology data from the central Morocco coastal area document a km-scale exhumation between the Permian and the Early/Middle Jurassic. The related erosion fed sediments to the subsiding Mesozoic basin to the northwest. Basement rocks along the transect were subsequently buried between the Late Jurassic and the Early Cretaceous. From late Early/Late Cretaceous onwards, rocks present along the transect were exhumed to their present-day position.The post-Variscan thermal and geological history of the Anti-Atlas belt in central Morocco is constrained with a transect constructed along strike of the belt (chapter 3). The initial episode occurred in the Late Triassic and led to a km-scale exhumation of crustal rocks by the end of the Middle Jurassic. The following phase was characterised by basement subsidence and occurred during the Late Jurassic and most of the Early Cretaceous. The basement rocks were then slowly brought to the surface after experiencing a km-scale exhumation throughout the Late Cretaceous and the Cenozoic. The exhumation episodes extended into the interior of the African tectonic plate, perhaps beyond the sampled belt itself. Exhumation rates and fluxes of material eroded from the hinterlands of the Moroccan rifted margin were quantified from the Permian (chapter 4). The high denudation rates, obtained in central Morocco during the Early to Middle Jurassic and in northern Morocco during the Neogene, are comparable to values typical of rift flank, domal, or structural uplifts. These are obtained in central Morocco during the Early to Middle Jurassic and in northern Morocco during the Neogene. Exhumation rates for other periods in northern to southern Morocco average around ‘normal’ denudation values. Periods of high production of sediments in the investigated source areas are the Permian, the Jurassic, the Early Cretaceous, and the NeogeneThe Phanerozoic evolution of source-to-sink systems in Morocco and surroundings is illustrated in several maps (chapter 5). Substantial shifts in the source areas were evidenced between the central and northern Moroccan domains during the Middle-Late Jurassic and between the Meseta and the Anti-Atlas during the Early-Late Cretaceous. Finally, the mechanisms responsible for the onset and subsistence of the unpredicted km-scale vertical movements are discussed (chapter 6). We propose that a combination of the large-scale crustal folding, mantle-driven dynamic topography, and thermal subsidence, superimposed to changes in climates, sea level and erodibility of the exposed rocks, were crucial to the timing, amplitude, and style of the observed vertical movements.The km-scale vertical movements will continue to be studied for years to come. Expectantly, this Thesis will deliver sufficiently robust grounds for further elaborated and integrated studies in Morocco and beyond.

scholarly journals The South-American distribution and southernmost record of Biomphalaria peregrina—a potential intermediate host of schistosomiasis

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3401 ◽  
Author(s):  
Alejandra Rumi ◽  
Roberto Eugenio Vogler ◽  
Ariel Aníbal Beltramino
Keyword(s):  
16S Rrna ◽  
South America ◽  
Potential Distribution ◽  
Phylogenetic Analyses ◽  
Distribution Model ◽  
South American ◽  
Intermediate Hosts ◽  
Morphological Examination ◽  
Widespread Species ◽  
Southern Patagonia

Schistosomiasis remains a major parasitic disease, endemic in large parts of South America. Five neotropical species of Biomphalaria have been found to act as intermediate hosts of Schistosoma mansoni in natural populations, while others have been shown to be susceptible in experimental infections, although not found infected in the field. Among these potential intermediate hosts, Biomphalaria peregrina represents the most widespread species in South America, with confirmed occurrence records from Venezuela to northern Patagonia. In this study, we report the southernmost record for the species at the Pinturas River, in southern Patagonia, which finding implies a southward reassessment of the limit for the known species of this genus. The identities of the individuals from this population were confirmed through morphological examination, and by means of two mitochondrial genes, cytochrome oxidase subunit I (COI) and 16S-rRNA. With both markers, phylogenetic analyses were conducted in order to compare the genetic background of individuals from the Pinturas River with previously genetically characterized strains of B. peregrina from various South-American locations. In addition, we produced a potential distribution model of B. peregrina in South America and identified the environmental variables that best predict that distribution. The model was estimated through a maximum entropy algorithm and run with occurrence points obtained from several sources, including the scientific literature and international databases, along with climatic and hydrographic variables. Different phylogenetic analyses with either the COI or 16S-rRNA sequences did not conflict, but rather gave very similar topological organizations. Two major groups were identified, with sequences from the Pinturas River grouping together with haplotypes from subtropical and temperate regions. The model developed had a satisfactory performance for the study area. We observed that the areas with higher habitat suitability were found to be mainly linked to subtropical and temperate regions of South America between 15° and 45° south latitude, with different moderate- and low-suitability areas outside this range. We also identified the coldest temperatures as the main predictors of the potential distribution of this snail. Susceptibility surveys would be required to evaluate if southern populations of B. peregrina still retain their potential as intermediate hosts of S. mansoni.

Bluetongue virus in South America: current status based on phylogenetic analysis

2021 ◽  
Author(s):  
Danilo Legisa ◽  
Maria José Dus Santos
Keyword(s):  
Phylogenetic Analysis ◽  
Maximum Likelihood ◽  
South America ◽  
Bluetongue Virus ◽  
Phylogenetic Analyses ◽  
Current Status ◽  
Accurate Information ◽  
South American ◽  
American Continent ◽  
Genetic Continuity

Bluetongue (BT) is an insect-borne disease affecting domestic and wild ruminants. Bluetongue virus (BTV) is the causative agent of the BT disease. BT outbreaks have been widely recorded worldwide. However, in the South American subcontinent, accurate information about the disease and molecular epidemiology is still lacking because little effort has been made to cover the region. This study comprises an exhaustive phylogenetic analysis including all BTV sequences available in databases and reports new Argentinean sequences for Seg 8 and Seg 9. Maximum-likelihood phylogenetic analyses were conducted for Seg 2, Seg 3, Seg 6, Seg 7, Seg 8, Seg 9 and Seg 10. Throughout the study, wide circulation and genetic continuity along the American continent were detected. Also, reassortment events are reported, and the historical virus introduction path into and through South America is suggested.

From Charles Darwin’s comments to the first mention of South American giant fossil birds: Auguste Bravard’s catalogue of fossil species from Argentina (1860) and its significance

2016 ◽  
Vol 187 (1) ◽  
pp. 41-53 ◽  
Author(s):  
Eric Buffetaut
Keyword(s):  
South America ◽  
Charles Darwin ◽  
Late Eocene ◽  
Fossil Birds ◽  
South American ◽  
Paris Basin ◽  
Fossil Species ◽  
Charles Lyell ◽  
Mammal Fauna

Abstract In 1860, the French geologist and palaeontologist Auguste Bravard (1803–1861) circulated a small number of copies of a hand-written and lithographed catalogue of the fossils he had collected in various parts of Argentina over a period of about eight years. Although the existence of this catalogue has been mentioned by various authors, it has never been really published in full. A facsimile reproduction is provided here. The contents of the catalogue and reactions to them are discussed, with special attention to comments in the correspondence between Charles Lyell and Charles Darwin. These comments were largely about Bravard’s identification among his fossils from Argentina of the genera Palaeotherium and Anoplotherium, well known components of the Late Eocene mammal fauna from the Montmartre gypsum, in the Paris Basin. This identification was later shown to be erroneous by Gervais, Burmeister and Ameghino. Bravard’s catalogue also includes what appears to be the first mention of fossil giant ground birds (Phorusrhacidae) in South America.

Determination of formation paleo-pressure and evolution process using gaseous hydrocarbon inclusions

2020 ◽  
Author(s):  
Cunjian Zhang ◽  
Jingdong Liu ◽  
Youlu Jiang
Keyword(s):  
Late Cretaceous ◽  
Middle Jurassic ◽  
Formation Mechanisms ◽  
Formation Pressure ◽  
Gas Reservoirs ◽  
Gaseous Hydrocarbon ◽  
Late Cretaceous Period ◽  
Cretaceous Period ◽  
Early Late ◽  
Vapor Liquid

<p>Research on overpressure evolution and its formation mechanisms is of great significance for revealing reservoir formation mechanisms and predicting formation pressures in oil and gas reservoirs before drilling. However, research methods addressing overpressure evolution are not without issues. The fluid inclusion PVT simulation and basin simulation can be used to investigate the paleo-pressure.</p> <p>The homogenization temperatures of inclusions were tested. The accuracy of the microscopic laser Raman spectroscopy analysis is too limited to fully test the components of gaseous hydrocarbon inclusions so that the organic components of the natural gas in the present-day gas reservoirs represented the gaseous hydrocarbon inclusions. In addition, the vapor-liquid ratio of gaseous hydrocarbon inclusions cannot be measured by CLSM. Firstly, A series of images at different slice depths was obtained by adjusting the focal length of a high-resolution microscope. Secondly, CorelDRAW software was used to calculate the areas of inclusions and bubbles; fitting functions were established between the inclusion areas and slice depths, and between the bubble areas and slice depths. Finally, the inclusion and bubble volumes were integrated to obtain the vapor-liquid ratios of the inclusions. PVTsim software can calculate the trapping pressures of inclusions. Combined with basin simulation, the evolution of paleo-pressure can be determined.</p> <p>The above methods were used to investigate the paleo-pressure of the Upper Triassic Xujiahe Formation in the northeast portion of the Sichuan Basin. Overpressure began to develop in the Middle Jurassic period. Due to hydrocarbon generation taking place, the formation pressure increased rapidly from the Middle Jurassic period to the early Late Cretaceous period. Since the early Late Cretaceous period, the formation pressure has gradually decreased due to tectonic uplift and erosion. From the Oligocene period to the present, the formation pressure have increased again in local areas due to tectonic compression.</p>

scholarly journals A Single Chromosome Unexpectedly Links Highly Divergent Isolates of Toxoplasma gondii

mBio ◽  
2011 ◽  
Vol 3 (1) ◽  
Author(s):  
Katelyn A. Walzer ◽  
Jon P. Boyle
Keyword(s):  
Toxoplasma Gondii ◽  
South America ◽  
North American ◽  
Phylogenetic Analyses ◽  
Unexpected Finding ◽  
Type I ◽  
South American ◽  
Single Chromosome ◽  
Content Type ◽  
The North

ABSTRACT Toxoplasma gondii is an obligate intracellular parasite that can cause disease in all warm-blooded animals studied to date, including humans. Over a billion people have been infected with this parasite worldwide. In Europe and North America, Toxoplasma has a clonal population structure, where only three lineages are highly dominant (strain types I, II, and III). Khan et al. [mBio 2(6): e00228-11, 2011] have carried out phylogenetic analyses on a large number of diverse strains from outside of these lineages and found evidence for a significant split between the clonal North American/European lineages and those in South America. In contrast to most of the genome, nearly all North American/European strains sampled, and the majority of South American strains sampled, harbored at least portions of a monomorphic chromosome Ia (Ia*). In contrast to previous models, these data suggest that the monomorphic haplotype originated in South America and migrated to the North. These authors propose that South American haplotype 12 was a precursor to modern-day type II, while South American haplotypes 6 and 9 crossed with haplotype 12 to give rise to the type I and III lineages, respectively. However, the findings reported by Khan et al. complicate the origin of chromosome Ia, since there are members of haplotypes 9 and 12 with nearly complete versions of Ia* and members of haplotypes 6 and 12 with over 50% of Ia*. This unexpected finding raises exciting new questions about how an entire common chromosome can be found within strains that are highly divergent at most other genomic loci.

The santonian through paleogene record of Proteaceae in the southern South America - Antarctic peninsula region

1998 ◽  
Vol 11 (4) ◽  
pp. 373 ◽  
Author(s):  
Rosemary A. Askin ◽  
Alicia M. Baldoni
Keyword(s):  
South America ◽  
Antarctic Peninsula ◽  
Late Cretaceous ◽  
Fossil Record ◽  
Type Species ◽  
Pollen Record ◽  
South American ◽  
Southern South America ◽  
Nothofagus Forest ◽  
The Antarctic

Proteaceous plants were an important component of the high-latitude Late Cretaceous–Paleogene podocarpaceous conifer and Nothofagus forest vegetation growing in high-rainfall temperate conditions. In the southern South America–Antarctic Peninsula region the fossil record of the Proteaceae comprises pollen, leaves, fruits and wood with affinities to the extant subfamilies Grevilleoideae, Proteoideae, and possibly Carnarvonioideae and Persoonioideae. The oldest reported occurrences of Proteaceae in this region are in the middle–late Santonian of the Antarctic Peninsula and include pollen of Proteacidites subscabratus Couper, with the addition in the Campanian of other species of Proteacidites and Propylipollis, Cranwellipollis spp. and Peninsulapollis spp. Diversity of proteaceous pollen increased through the Campanian and Maastrichtian, reflecting the spread of Proteaceae along the Antarctic Peninsula and into South America. Both endemic species and species derived from the Australian region are represented. Compared to coeval Australian assemblages, however, proteaceous diversity remained relatively low. Interestingly, Beauprea-type species (Beaupreaidites spp., Peninsulapollis spp.) are common and varied in the Antarctic Peninsula from Campanian into the Eocene, yet the South American pollen record does not include these forms, except for rare Peninsulapollis gillii. Possibly drier conditions may have discouraged northward migration of this group. South American fossil proteaceous taxa are primarily related to Grevilleoideae, a trend that continues into the modern flora on that continent.

scholarly journals Mountain radiations are not only rapid and recent: ancient diversification of South American frog and lizard families related to Paleogene Andean orogeny and Cenozoic climate variations

2021 ◽  
Author(s):  
Lydian M Boschman ◽  
Fabien L Condamine
Keyword(s):  
South America ◽  
Late Cretaceous ◽  
Large Fraction ◽  
High Elevation ◽  
Late Eocene ◽  
Strong Positive Correlation ◽  
Mountain Building ◽  
Extinction Rates ◽  
Surface Uplift ◽  
History Of

Mountainous areas host a disproportionately large fraction of Earth's biodiversity, suggesting a causal relationship between mountain building and biological diversification. Mountain clade radiations are generally associated with environmental heterogeneity, and with ecological opportunities created during the formation of high-elevation habitats. In South America, most documented Andean clade radiations are recent (Neogene) and rapid. However, so far only few studies have explicitly linked Andean elevation to species diversification. Here, we present a curve of Andean elevation based on a recent compilation of paleo-elevational data back to the Late Cretaceous, and analyse the diversification history of six Andean frog and lizard families that originated equally far back in time. For two clades (Aromobatidae and Leptodactylidae), we find that they diversified most rapidly during the early phase of mountain building (Late Cretaceous - Paleogene), when the first high-elevation habitats emerged in South America. The diversification of two other clades (Centrolenidae and Dendrobatidae) are correlated with Cenozoic temperature variations, with higher speciation (and for Dendrobatidae, also higher extinction) rates during warm periods. The last two clades (Hemiphractidae and Liolaemidae) are best explained by environment-independent diversification, although for Liolaemidae, an almost equally strong positive correlation was found between speciation and Andean elevation since the late Eocene. Our findings imply that throughout the long-lived history of surface uplift in the Andes, mountain building drove the diversification of different clades at different times, while not directly affecting other clades. Our study illustrates the importance of paleogeographic reconstructions that capture the complexity and heterogeneity of mountain building in our understanding of the effects that a changing environment plays in shaping biodiversity patterns observed today.

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