scholarly journals Endocast of the Late Triassic (Carnian) dinosaur Saturnalia tupiniquim: implications for the evolution of brain tissue in Sauropodomorpha

2018 ◽  
Author(s):  
Mario Bronzati ◽  
Oliver W M Rauhut ◽  
Jonathas S Bittencourt ◽  
Max C. Langer
Keyword(s):  
South America ◽  
Brain Tissue ◽  
Evolutionary History ◽  
Morphological Changes ◽  
Volume Reduction ◽  
Late Triassic ◽  
History Of

The evolutionary history of dinosaurs might date back to the fist stages of the Triassic (c. 250– 240 Ma), but the oldest unequivocal records of the group come from Late Triassic (Carnian – c. 230 Ma) rocks of South America. Here, we present the fist braincase endocast of a Carnian dinosaur, the sauropodomorph Saturnalia tupiniquim, and provide new data regarding the evolution of the flccular and paraflccular lobe of the cerebellum (FFL), which has been extensively discussed in the fild of palaeoneurology. Previous studies proposed that the development of a permanent quadrupedal stance was one of the factors leading to the volume reduction of the FFL of sauropods. However, based on the new data for S. tupiniquim we identifid a fist moment of FFL volume reduction in nonsauropodan Sauropodomorpha, preceding the acquisition of a fully quadrupedal stance. Analysing variations in FFL volume alongside other morphological changes in the group, we suggest that this reduction is potentially related to the adoption of a more restricted herbivore diet. In this context, the FFL of sauropods might represent a vestigial trait, retained in a reduced version from the bipedal and predatory early sauropodomorphs.

scholarly journals Triassic–Jurassic mass extinction as trigger for the Mesozoic radiation of crocodylomorphs

2013 ◽  
Vol 9 (3) ◽  
pp. 20130095 ◽  
Author(s):  
Olja Toljagić ◽  
Richard J. Butler
Keyword(s):  
Mass Extinction ◽  
Evolutionary History ◽  
Morphological Diversity ◽  
Early Jurassic ◽  
Late Triassic ◽  
Time Interval ◽  
Significant Shift ◽  
History Of ◽  
Larger Sample ◽  
Lineage Diversity

Pseudosuchia, one of the two main clades of Archosauria (Reptilia: Diapsida), suffered a major decline in lineage diversity during the Triassic–Jurassic (TJ) mass extinction (approx. 201 Ma). Crocodylomorpha, including living crocodilians and their extinct relatives, is the only group of pseudosuchians that survived into the Jurassic. We reassess changes in pseudosuchian morphological diversity (disparity) across this time interval, using considerably larger sample sizes than in previous analyses. Our results show that metrics of pseudosuchian disparity did not change significantly across the TJ boundary, contrasting with previous work suggesting low pseudosuchian disparity in the Early Jurassic following the TJ mass extinction. However, a significant shift in morphospace occupation between Late Triassic and Early Jurassic taxa is recognized, suggesting that the TJ extinction of many pseudosuchian lineages was followed by a major and geologically rapid adaptive radiation of crocodylomorphs. This marks the onset of the spectacularly successful evolutionary history of crocodylomorphs in Jurassic and Cretaceous ecosystems.

Taphonomic bias and the evolutionary history of the family Cidaridae (Echinodermata: Echinoidea)

Paleobiology ◽  
1992 ◽  
Vol 18 (1) ◽  
pp. 50-79 ◽  
Author(s):  
Benjamin J. Greenstein
Keyword(s):  
Type Species ◽  
Evolutionary History ◽  
Middle Triassic ◽  
Upper Jurassic ◽  
Late Triassic ◽  
Type Specimens ◽  
Fossil Material ◽  
Group I ◽  
The Family ◽  
History Of

The class Echinoidea apparently originated during the Ordovician Period and diversified slowly through the Paleozoic Era. The clade then mushroomed in diversity beginning in Late Triassic time and continued expanding into the present. Although this evolutionary history is generally accepted, the taphonomic overprint affecting it has not been explored. To gain a more accurate perception of the evolutionary history of the group, I have compared the diversity history of the family Cidaridae (Echinodermata: Echinoidea) with the preservational style of fossil type species using literature-derived data. The Cidaridae apparently originated in Middle Triassic time and diversified slowly through the Neocomian (Early Cretaceous). Diversity was maintained through the remainder of the Cretaceous and Tertiary Periods, reflecting the diversity history of the subclass. Characterization of the preservational style of type fossil material for the family revealed the following breakdown of preservational states: 60% of species were described on the basis of disarticulated skeletal material, primarily spines; 20% based on intact coronas denuded of spines, apical system, Aristotle's lantern and peristomial plates; 10% based on large coronal fragments; and 10% based on other skeletal elements. This distribution may represent the effect of a disarticulation threshold on the condition of echinoid carcasses before final burial and suggests that preservation of intact specimens may be very unlikely. For cidaroids, previous work has suggested that this threshold is likely to be reached after 7 days of decay.Comparison of the diversity history of the Cidaridae with the preservation data reveals that characteristic patterns of taphonomic overprint have affected the group since its origination in Middle Triassic time, and the nature of that overprint has changed over time: the early diversity history of the group is characterized by occurrences of fragmented fossil material, with spines predominant; further radiation of the group in mid-Jurassic time coincided with an increase in modes of preservation, ranging between exceptionally well-preserved material and disarticulated skeletal elements. Finally, type material is more rarely described from younger stratigraphic intervals (Miocene–Pleistocene) and consists predominantly of disarticulated skeletal elements and coronal fragments larger than an interambulacrum in size. Intact, denuded coronas are noticeably lacking.The number of type species of Cidaridae described in each stratigraphic interval has not been consistent during post-Paleozoic time. Middle Triassic, Malm (Upper Jurassic), Senonian (Upper Cretaceous) and Eocene series yielded significantly (α = .05) higher numbers of type specimens per million years, while the Lias (Lower Jurassic), Dogger (Mid-Jurassic), Lower Cretaceous and Paleocene yielded significantly (α = .05) lower numbers of type specimens per million years. This may be the result of a combination of taxonomic, sampling, and geographical biases.

The evolutionary history of Senna ser. Aphyllae (Leguminosae–Caesalpinioideae), an endemic clade of southern South America

2017 ◽  
Vol 303 (10) ◽  
pp. 1351-1366
Author(s):  
Federico O. Robbiati ◽  
Ana Anton ◽  
Brigitte Marazzi ◽  
Marilyn Vásquez-Cruz ◽  
Renée H. Fortunato
Keyword(s):  
South America ◽  
Evolutionary History ◽  
Southern South America ◽  
History Of

scholarly journals Correction: On the Evolutionary History of Uleiella chilensis, a Smut Fungus Parasite of Araucaria araucana in South America: Uleiellales ord. nov. in Ustilaginomycetes

PLoS ONE ◽  
2016 ◽  
Vol 11 (3) ◽  
pp. e0152646
Author(s):  
Kai Riess ◽  
Max E. Schön ◽  
Matthias Lutz ◽  
Heinz Butin ◽  
Franz Oberwinkler ◽  
...  
Keyword(s):  
South America ◽  
Evolutionary History ◽  
Smut Fungus ◽  
Araucaria Araucana ◽  
History Of

scholarly journals A new stem turtle from the Middle Jurassic of Scotland: new insights into the evolution and palaeoecology of basal turtles

2008 ◽  
Vol 276 (1658) ◽  
pp. 879-886 ◽  
Author(s):  
Jérémy Anquetin ◽  
Paul M Barrett ◽  
Marc E.H Jones ◽  
Scott Moore-Fay ◽  
Susan E Evans
Keyword(s):  
Middle Jurassic ◽  
Late Jurassic ◽  
Evolutionary History ◽  
Sister Group ◽  
Late Triassic ◽  
Sister Group Relationship ◽  
New Taxon ◽  
Crown Group ◽  
History Of ◽  
Isle Of Skye

The discovery of a new stem turtle from the Middle Jurassic (Bathonian) deposits of the Isle of Skye, Scotland, sheds new light on the early evolutionary history of Testudinata. Eileanchelys waldmani gen. et sp. nov. is known from cranial and postcranial material of several individuals and represents the most complete Middle Jurassic turtle described to date, bridging the morphological gap between basal turtles from the Late Triassic–Early Jurassic and crown-group turtles that diversify during the Late Jurassic. A phylogenetic analysis places the new taxon within the stem group of Testudines (crown-group turtles) and suggests a sister-group relationship between E. waldmani and Heckerochelys romani from the Middle Jurassic of Russia. Moreover, E. waldmani also demonstrates that stem turtles were ecologically diverse, as it may represent the earliest known aquatic turtle.

scholarly journals Gene Flow between Divergent Cereal- and Grass-Specific Lineages of the Rice Blast Fungus Magnaporthe oryzae

mBio ◽  
2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Pierre Gladieux ◽  
Bradford Condon ◽  
Sebastien Ravel ◽  
Darren Soanes ◽  
Joao Leodato Nunes Maciel ◽  
...  
Keyword(s):  
Gene Flow ◽  
South America ◽  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Evolutionary History ◽  
Blast Disease ◽  
Whole Genome ◽  
Disease Emergence ◽  
Wheat Blast ◽  
History Of

ABSTRACT Delineating species and epidemic lineages in fungal plant pathogens is critical to our understanding of disease emergence and the structure of fungal biodiversity and also informs international regulatory decisions. Pyricularia oryzae (syn. Magnaporthe oryzae) is a multihost pathogen that infects multiple grasses and cereals, is responsible for the most damaging rice disease (rice blast), and is of growing concern due to the recent introduction of wheat blast to Bangladesh from South America. However, the genetic structure and evolutionary history of M. oryzae, including the possible existence of cryptic phylogenetic species, remain poorly defined. Here, we use whole-genome sequence information for 76 M. oryzae isolates sampled from 12 grass and cereal genera to infer the population structure of M. oryzae and to reassess the species status of wheat-infecting populations of the fungus. Species recognition based on genealogical concordance, using published data or extracting previously used loci from genome assemblies, failed to confirm a prior assignment of wheat blast isolates to a new species (Pyricularia graminis-tritici). Inference of population subdivisions revealed multiple divergent lineages within M. oryzae, each preferentially associated with one host genus, suggesting incipient speciation following host shift or host range expansion. Analyses of gene flow, taking into account the possibility of incomplete lineage sorting, revealed that genetic exchanges have contributed to the makeup of multiple lineages within M. oryzae. These findings provide greater understanding of the ecoevolutionary factors that underlie the diversification of M. oryzae and highlight the practicality of genomic data for epidemiological surveillance in this important multihost pathogen. IMPORTANCE Infection of novel hosts is a major route for disease emergence by pathogenic microorganisms. Understanding the evolutionary history of multihost pathogens is therefore important to better predict the likely spread and emergence of new diseases. Magnaporthe oryzae is a multihost fungus that causes serious cereal diseases, including the devastating rice blast disease and wheat blast, a cause of growing concern due to its recent spread from South America to Asia. Using whole-genome analysis of 76 fungal strains from different hosts, we have documented the divergence of M. oryzae into numerous lineages, each infecting a limited number of host species. Our analyses provide evidence that interlineage gene flow has contributed to the genetic makeup of multiple M. oryzae lineages within the same species. Plant health surveillance is therefore warranted to safeguard against disease emergence in regions where multiple lineages of the fungus are in contact with one another.

scholarly journals Gene flow between divergent cereal‐ and grass-specific lineages of the rice blast fungus Magnaporthe oryzae

2017 ◽  
Author(s):  
Pierre Gladieux ◽  
Bradford Condon ◽  
Sebastien Ravel ◽  
Darren Soanes ◽  
Joao Leodato Nunes Maciel ◽  
...  
Keyword(s):  
Gene Flow ◽  
South America ◽  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Evolutionary History ◽  
Whole Genome ◽  
Disease Emergence ◽  
Wheat Blast ◽  
Host Pathogen ◽  
History Of

AbstractDelineating species and epidemic lineages in fungal plant pathogens is critical to our understanding of disease emergence and the structure of fungal biodiversity, and also informs international regulatory decisions. Pyricularia oryzae (syn. Magnaporthe oryzae) is a multi-host pathogen that infects multiple grasses and cereals, is responsible for the most damaging rice disease (rice blast), and of growing concern due to the recent introduction of wheat blast to Bangladesh from South America. However, the genetic structure and evolutionary history of M. oryzae, including the possible existence of cryptic phylogenetic species, remain poorly defined. Here, we use whole-genome sequence information for 76 M. oryzae isolates sampled from 12 grass and cereal genera to infer the population structure of M. oryzae, and to reassess the species status of wheat-infecting populations of the fungus. Species recognition based on genealogical concordance, using published data or extracting previously-used loci from genome assemblies, failed to confirm a prior assignment of wheat blast isolates to a new species (Pyricularia graminis tritici). Inference of population subdivisions revealed multiple divergent lineages within M. oryzae, each preferentially associated with one host genus, suggesting incipient speciation following host shift or host range expansion. Analyses of gene flow, taking into account the possibility of incomplete lineage sorting, revealed that genetic exchanges have contributed to the makeup of multiple lineages within M. oryzae. These findings provide greater understanding of the eco-evolutionary factors that underlie the diversification of M. oryzae and highlight the practicality of genomic data for epidemiological surveillance in this important multi-host pathogen.ImportanceInfection of novel hosts is a major route for disease emergence by pathogenic micro-organisms. Understanding the evolutionary history of multi-host pathogens is therefore important to better predict the likely spread and emergence of new diseases. Magnaporthe oryzae is a multi-host fungus that causes serious cereal diseases, including the devastating rice blast disease, and wheat blast, a cause of growing concern due to its recent spread from South America to Asia. Using whole genome analysis of 76 fungal strains from different hosts, we have documented the divergence of M. oryzae into numerous lineages, each infecting a limited number of host species. Our analyses provide evidence that inter-lineage gene flow has contributed to the genetic makeup of multiple M. oryzae lineages within the same species. Plant health surveillance is therefore warranted to safeguard against disease emergence in regions where multiple lineages of the fungus are in contact with one another.

scholarly journals Diversity and paleoenvironmental implications of an elasmobranch assemblage from the Oligocene–Miocene boundary of Ecuador

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9051
Author(s):  
Jorge D. Carrillo-Briceño ◽  
Jaime A. Villafaña ◽  
Carlos De Gracia ◽  
F. Fernando Flores-Alcívar ◽  
René Kindlimann ◽  
...  
Keyword(s):  
South America ◽  
Evolutionary History ◽  
New Records ◽  
Tropical America ◽  
History Of ◽  
Fossil Site ◽  
The Rich ◽  
Fossil Records ◽  
Santa Elena ◽  
Open Shelf

The occurrence and diversity of elasmobranchs from the Oligocene–Miocene boundary from Tropical America is poorly known in comparison with the paleodiversity from younger Neogene intervals of the region. Here we describe a new elasmobranch assemblage from the rich fossil site of Montañita-Olón (Dos Bocas Formation, Santa Elena, Ecuador), where other vertebrates have already been described: for example, sea turtles and cetaceans. We report a total of 27 elasmobranch taxa, 19 of which are new fossil records for Ecuador, 10 new records for the Central Eastern Pacific and four new records for South America. Additionally, in order to reconstruct the environment where these marine remains were deposited, we performed abundance, paleobathymetric and habitat preference analyses, concluding that they were likely deposited in an outer neritic (open shelf) environment. The study of Oligocene and early Miocene marine elasmobranchs faunas in Tropical America is key to addressing the issues in the evolutionary history of this group.

scholarly journals A basal thunnosaurian from Iraq reveals disparate phylogenetic origins for Cretaceous ichthyosaurs

2013 ◽  
Vol 9 (4) ◽  
pp. 20130021 ◽  
Author(s):  
Valentin Fischer ◽  
Robert M. Appleby ◽  
Darren Naish ◽  
Jeff Liston ◽  
James B. Riding ◽  
...  
Keyword(s):  
Middle East ◽  
Early Cretaceous ◽  
Late Jurassic ◽  
Evolutionary History ◽  
Early Jurassic ◽  
Late Triassic ◽  
Low Diversity ◽  
History Of

Cretaceous ichthyosaurs have typically been considered a small, homogeneous assemblage sharing a common Late Jurassic ancestor. Their low diversity and disparity have been interpreted as indicative of a decline leading to their Cenomanian extinction. We describe the first post-Triassic ichthyosaur from the Middle East, Malawania anachronus gen. et sp. nov. from the Early Cretaceous of Iraq, and re-evaluate the evolutionary history of parvipelvian ichthyosaurs via phylogenetic and cladogenesis rate analyses. Malawania represents a basal grade in thunnosaurian evolution that arose during a major Late Triassic radiation event and was previously thought to have gone extinct during the Early Jurassic. Its pectoral morphology appears surprisingly archaic, retaining a forefin architecture similar to that of its Early Jurassic relatives. After the initial latest Triassic radiation of early thunnosaurians, two subsequent large radiations produced lineages with Cretaceous representatives, but the radiation events themselves are pre-Cretaceous. Cretaceous ichthyosaurs therefore include distantly related lineages, with contrasting evolutionary histories, and appear more diverse and disparate than previously supposed.

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