scholarly journals Late Toarcian marine gastropods from the Cleveland Basin, UK: systematics, palaeobiogeography and contribution to biotic recovery from the early Toarcian extinction event

2019 ◽  
Author(s):  
Mariel Ferrari ◽  
Crispin TS Little ◽  
Jed W Atkinson
Keyword(s):  
Mass Extinction ◽  
Taxonomic Composition ◽  
The Other ◽  
Gastropod Species ◽  
Marine Gastropods ◽  
Potential Explanation ◽  
Biotic Recovery ◽  
Extinction Event ◽  
Sandstone Formation ◽  
Mass Extinction Event

As part of a study to evaluate the recovery from the early Toarcian extinction event in the Cleveland Basin, 477 new gastropod specimens were collected from mid-late Toarcian rocks of the Ravenscar section, North Yorkshire, UK. The gastropods were preserved in two modes: 1) specimens preserved with recrystallized shells, mainly in the Whitby Mudstone Formation, but also some in the Blea Wyke Sandstone Formation; 2) specimens preserved as external moulds in mineralized patches of shells in the Yellow Sandstone Member. The fossil assemblage comprised fifteen species, of which three are new: Katosira? bicarinata sp. nov., Turritelloidea stepheni sp. nov. and Striactaenonina elegans sp. nov. Four species are described in open nomenclature, as Tricarilda? sp. Jurilda sp., Cylindrobullina sp. and Cossmannina sp. The other species have previously been described: Coelodiscus minutus (Schübler in Zieten), Procerithium quadrilineatum (Römer), Pseudokatosira undulata (Benz in von Zieten), Palaeorissoina aff. acuminata (Gründel), Pietteia unicarinata (Hudleston), Globularia cf. canina (Hudleston), Striactaeonina cf. richterorum Schulbert & Nützel, Striactaenonina aff. tenuistriata (Hudleston) and Sulcoactaeon sedgvici (Phillips). Most of these species are the earliest records of their respective genera and show palaeobiogeographical connections with contemporary gastropod associations from other regions of Europe and South America. The taxonomic composition of the late Toarcian Cleveland Basin gastropod assemblage differs substantially from the faunas of the late Pliensbachian and early Toarcian Tenuicostatum Zone, showing the strong effect of the early Toarcian mass extinction event on the marine gastropod communities in the basin. Only a few gastropod species are shared between the late Toarcian faunas and the much more diverse Aalenian gastropod faunas in the Cleveland Basin, suggesting there was a facies control on gastropod occurrences at that time. This is also a potential explanation for the taxonomic differences between the late Toarcian gastropod faunas in the Cleveland Basin and those in France, and Northern and Southern Germany.

scholarly journals Late Toarcian marine gastropods from the Cleveland Basin, UK: systematics, palaeobiogeography and contribution to biotic recovery from the early Toarcian extinction event

2019 ◽  
Author(s):  
Mariel Ferrari ◽  
Crispin TS Little ◽  
Jed W Atkinson
Keyword(s):  
Mass Extinction ◽  
Taxonomic Composition ◽  
The Other ◽  
Gastropod Species ◽  
Marine Gastropods ◽  
Potential Explanation ◽  
Biotic Recovery ◽  
Extinction Event ◽  
Sandstone Formation ◽  
Mass Extinction Event

As part of a study to evaluate the recovery from the early Toarcian extinction event in the Cleveland Basin, 477 new gastropod specimens were collected from mid-late Toarcian rocks of the Ravenscar section, North Yorkshire, UK. The gastropods were preserved in two modes: 1) specimens preserved with recrystallized shells, mainly in the Whitby Mudstone Formation, but also some in the Blea Wyke Sandstone Formation; 2) specimens preserved as external moulds in mineralized patches of shells in the Yellow Sandstone Member. The fossil assemblage comprised fifteen species, of which three are new: Katosira? bicarinata sp. nov., Turritelloidea stepheni sp. nov. and Striactaenonina elegans sp. nov. Four species are described in open nomenclature, as Tricarilda? sp. Jurilda sp., Cylindrobullina sp. and Cossmannina sp. The other species have previously been described: Coelodiscus minutus (Schübler in Zieten), Procerithium quadrilineatum (Römer), Pseudokatosira undulata (Benz in von Zieten), Palaeorissoina aff. acuminata (Gründel), Pietteia unicarinata (Hudleston), Globularia cf. canina (Hudleston), Striactaeonina cf. richterorum Schulbert & Nützel, Striactaenonina aff. tenuistriata (Hudleston) and Sulcoactaeon sedgvici (Phillips). Most of these species are the earliest records of their respective genera and show palaeobiogeographical connections with contemporary gastropod associations from other regions of Europe and South America. The taxonomic composition of the late Toarcian Cleveland Basin gastropod assemblage differs substantially from the faunas of the late Pliensbachian and early Toarcian Tenuicostatum Zone, showing the strong effect of the early Toarcian mass extinction event on the marine gastropod communities in the basin. Only a few gastropod species are shared between the late Toarcian faunas and the much more diverse Aalenian gastropod faunas in the Cleveland Basin, suggesting there was a facies control on gastropod occurrences at that time. This is also a potential explanation for the taxonomic differences between the late Toarcian gastropod faunas in the Cleveland Basin and those in France, and Northern and Southern Germany.

scholarly journals Spreadsheets to expedite taxonomic publications by automatic generation of morphological descriptions and specimen lists

Zootaxa ◽  
2019 ◽  
Vol 4624 (1) ◽  
pp. 147-150
Author(s):  
IVAN L. F. MAGALHAES
Keyword(s):  
Mass Extinction ◽  
Biodiversity Loss ◽  
Automatic Generation ◽  
The Other ◽  
Number Of Species ◽  
Taxonomic Descriptions ◽  
Extinction Event ◽  
Mass Extinction Event

It is now generally accepted that we are going through a major mass extinction event that is causing biodiversity loss at alarming rates (Barnosky et al. 2011). We also know that many species remain to be formally described (e.g. Huber 2014), and concerns have been raised as to whether we will be able to document these before they go extinct (Costello et al. 2013). On one hand, the number of recognized species increases exponentially (e.g. Agnarsson et al. 2013; Sangster & Luksenburg 2015). On the other, taxonomic descriptions are becoming more complete and detailed, which is necessarily more time-consuming, leading to an overall decline in the number of species described per taxonomist (Sangster & Luksenburg 2015). In this scenario, any method or protocol that increases efficiency in taxonomic descriptions is welcome. 

THE RECORD OF ENVIRONMENTAL CHANGE IN NORTHEASTERN PANTHALASSA DIRECTLY PRECEDING THE END-TRIASSIC MASS EXTINCTION EVENT

2019 ◽  
Author(s):  
Ekaterina Larina ◽  
◽  
David J. Bottjer ◽  
Frank A. Corsetti ◽  
William M. Berelson ◽  
...  
Keyword(s):  
Environmental Change ◽  
Mass Extinction ◽  
Extinction Event ◽  
Mass Extinction Event

SEDIMENTARY MERCURY CONCENTRATIONS AND ISOTOPES ACROSS THE END-CRETACEOUS MASS EXTINCTION EVENT FROM NEW JERSEY

2020 ◽  
Author(s):  
Marisa D. Knight ◽  
◽  
Runsheng Yin ◽  
Clara L. Meier ◽  
James V. Browning ◽  
...  
Keyword(s):  
New Jersey ◽  
Mass Extinction ◽  
Extinction Event ◽  
Mass Extinction Event

scholarly journals Dinosaurs in decline tens of millions of years before their final extinction

2016 ◽  
Vol 113 (18) ◽  
pp. 5036-5040 ◽  
Author(s):  
Manabu Sakamoto ◽  
Michael J. Benton ◽  
Chris Venditti
Keyword(s):  
Mass Extinction ◽  
Marked Reduction ◽  
Evolutionary Dynamics ◽  
General Pattern ◽  
Extinction Rate ◽  
Catastrophic Event ◽  
Extinction Event ◽  
Mass Extinction Event ◽  
First Time

Whether dinosaurs were in a long-term decline or whether they were reigning strong right up to their final disappearance at the Cretaceous–Paleogene (K-Pg) mass extinction event 66 Mya has been debated for decades with no clear resolution. The dispute has continued unresolved because of a lack of statistical rigor and appropriate evolutionary framework. Here, for the first time to our knowledge, we apply a Bayesian phylogenetic approach to model the evolutionary dynamics of speciation and extinction through time in Mesozoic dinosaurs, properly taking account of previously ignored statistical violations. We find overwhelming support for a long-term decline across all dinosaurs and within all three dinosaurian subclades (Ornithischia, Sauropodomorpha, and Theropoda), where speciation rate slowed down through time and was ultimately exceeded by extinction rate tens of millions of years before the K-Pg boundary. The only exceptions to this general pattern are the morphologically specialized herbivores, the Hadrosauriformes and Ceratopsidae, which show rapid species proliferations throughout the Late Cretaceous instead. Our results highlight that, despite some heterogeneity in speciation dynamics, dinosaurs showed a marked reduction in their ability to replace extinct species with new ones, making them vulnerable to extinction and unable to respond quickly to and recover from the final catastrophic event.

scholarly journals New Biochronological Scales of Planktic Foraminifera for the Early Danian Based on High-Resolution Biostratigraphy

Geosciences ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 479
Author(s):  
Ignacio Arenillas ◽  
Vicente Gilabert ◽  
José A. Arz
Keyword(s):  
High Resolution ◽  
Mass Extinction ◽  
Quantitative Data ◽  
Qualitative Data ◽  
Rapid Evolution ◽  
Planktic Foraminifera ◽  
Middle Latitudes ◽  
Evolutionary Radiation ◽  
Extinction Event ◽  
Mass Extinction Event

After the Cretaceous/Paleogene boundary (KPB) catastrophic mass extinction event, an explosive evolutionary radiation of planktic foraminifera took place in consequence of the prompt occupation of empty niches. The rapid evolution of new species makes it possible to establish high-resolution biozonations in the lower Danian. We propose two biostratigraphic scales for low-to-middle latitudes spanning the first two million years of the Danian. The first is based on qualitative data and includes four biozones: the Guembelitria cretacea Zone (Dan1), the Parvularugoglobigerina longiapertura Zone (Dan2), the Parvularugoglobigerina eugubina Zone (Dan3), and the Parasubbotina pseudobulloides Zone (Dan4). The latter two are divided into several sub-biozones: the Parvularugoglobigerina sabina Subzone (Dan3a) and the Eoglobigerina simplicissima Subzone (Dan3b) for the Pv. eugubina Zone, and the Praemurica taurica Subzone (Dan4a), the Subbotina triloculinoides Subzone (Dan4b), and the Globanomalina compressa Subzone (Dan4c) for the P. pseudobulloides Zone. The second scale is based on quantitative data and includes three acme-zones (abundance zones): the Guembelitria Acme-zone (DanAZ1), the Parvularugoglobigerina-Palaeoglobigerina Acme-zone (DanAZ2), and the Woodringina-Chiloguembelina Acme-zone (DanAZ3). Both biozonations are based on high-resolution samplings of the most continuous sections of the lower Danian worldwide and have been calibrated with recent magnetochronological and astrochronological dating.

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