Radiolarian biodiversity dynamics through the Triassic and Jurassic: implications for proximate causes of the end-Triassic mass extinction

Paleobiology ◽  
10.1666/14007 ◽  
2014 ◽  
Vol 40 (4) ◽  
pp. 625-639 ◽  
Author(s):  
Ádám T. Kocsis ◽  
Wolfgang Kiessling ◽  
József Pálfy
Keyword(s):  
Ocean Acidification ◽  
Mass Extinction ◽  
Environmental Parameters ◽  
Late Triassic ◽  
Control Group ◽  
Oceanic Anoxic Event ◽  
Extinction Rates ◽  
Extinction Peak ◽  
Using Data ◽  
Environmental Events

Within a ∼60-Myr interval in the Late Triassic to Early Jurassic, a major mass extinction took place at the end of Triassic, and several biotic and environmental events of lesser magnitude have been recognized. Climate warming, ocean acidification, and a biocalcification crisis figure prominently in scenarios for the end-Triassic event and have been also suggested for the early Toarcian. Radiolarians, as the most abundant silica-secreting marine microfossils of the time, provide a control group against marine calcareous taxa in testing selectivity and responses to changing environmental parameters. We analyzed the origination and extinction rates of radiolarians, using data from the Paleobiology Database and employing sampling standardization, the recently developed gap-filler equations and an improved stratigraphic resolution at the substage level. The major end-Triassic event is well-supported by a late Rhaetian peak in extinction rates. Because calcifying and siliceous organisms appear similarly affected, we consider global warming a more likely proximate trigger of the extinctions than ocean acidification. The previously reported smaller events of radiolarian turnover fail to register above background levels in our analyses. The apparent early Norian extinction peak is not significant compared to the long-term trajectory, and is probably a sampling artifact. The Toarcian Oceanic Anoxic Event, previously also thought to have caused a significant radiolarian turnover, did not significantly affect the group. Radiolarian diversity history appears unique and complexly forced, as its trajectory parallels major calcareous fossil groups at some events and deviates at others.

scholarly journals Trajectories of Late Permian – Jurassic radiolarian extinction rates: no evidence for an end-Triassic mass extinction

Fossil Record ◽  
2011 ◽  
Vol 14 (1) ◽  
pp. 95-101 ◽  
Author(s):  
W. Kiessling ◽  
T. Danelian
Keyword(s):  
Calcium Carbonate ◽  
Ocean Acidification ◽  
Mass Extinction ◽  
Late Permian ◽  
Extinction Rates ◽  
Evolutionary Response

The hypothesis that ocean acidification was a proximate trigger of the marine end-Triassic mass extinction rests on the assumption that taxa that strongly invest in the secretion of calcium-carbonate skeletons were significantly more affected by the crisis than other taxa. An argument against this hypothesis is the great extinction toll of radiolarians that has been reported from work on local sections. Radiolarians have siliceous tests and thus should be less affected by ocean acidification. We compiled taxonomically vetted occurrences of late Permian and Mesozoic radiolarians and analyzed extinction dynamics of radiolarian genera. Although extinction rates were high at the end of the Triassic, there is no evidence for a mass extinction in radiolarians but rather significantly higher background extinction in the Triassic than in the Jurassic. Although the causes for this decline in background extinction levels remain unclear, the lack of a major evolutionary response to the end-Triassic event, gives support for the hypothesis that ocean acidification was involved in the dramatic extinctions of many calcifying taxa. <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.201000017" target="_blank">10.1002/mmng.201000017</a>

scholarly journals Modelling determinants of extinction across two Mesozoic hyperthermal events

2018 ◽  
Vol 285 (1889) ◽  
pp. 20180404 ◽  
Author(s):  
Alexander M. Dunhill ◽  
William J. Foster ◽  
Sandro Azaele ◽  
James Sciberras ◽  
Richard J. Twitchett
Keyword(s):  
Mass Extinction ◽  
Marine Organisms ◽  
Early Jurassic ◽  
Late Triassic ◽  
Global Database ◽  
Extinction Rates ◽  
Multivariate Modelling ◽  
Hyperthermal Events ◽  
Extinction Selectivity ◽  
Extinction Events

The Late Triassic and Early Toarcian extinction events are both associated with greenhouse warming events triggered by massive volcanism. These Mesozoic hyperthermals were responsible for the mass extinction of marine organisms and resulted in significant ecological upheaval. It has, however, been suggested that these events merely involved intensification of background extinction rates rather than significant shifts in the macroevolutionary regime and extinction selectivity. Here, we apply a multivariate modelling approach to a vast global database of marine organisms to test whether extinction selectivity varied through the Late Triassic and Early Jurassic. We show that these hyperthermals do represent shifts in the macroevolutionary regime and record different extinction selectivity compared to background intervals of the Late Triassic and Early Jurassic. The Late Triassic mass extinction represents a more profound change in selectivity than the Early Toarcian extinction but both events show a common pattern of selecting against pelagic predators and benthic photosymbiotic and suspension-feeding organisms, suggesting that these groups of organisms may be particularly vulnerable during episodes of global warming. In particular, the Late Triassic extinction represents a macroevolutionary regime change that is characterized by (i) the change in extinction selectivity between Triassic background intervals and the extinction event itself; and (ii) the differences in extinction selectivity between the Late Triassic and Early Jurassic as a whole.

scholarly journals Modelling determinants of extinction across two Mesozoic hyperthermal events

2018 ◽  
Author(s):  
Alexander Dunhill ◽  
William J. Foster ◽  
Sandro Azaele ◽  
James Sciberras ◽  
Richard J. Twitchett
Keyword(s):  
Mass Extinction ◽  
Marine Organisms ◽  
Early Jurassic ◽  
Late Triassic ◽  
Global Database ◽  
Extinction Rates ◽  
Multivariate Modelling ◽  
Hyperthermal Events ◽  
Extinction Selectivity ◽  
Extinction Events

The Late Triassic and early Toarcian extinction events are both associated with greenhouse warming events triggered by massive volcanism. These Mesozoic hyperthermals were responsible for the mass extinction of marine organisms and resulted in significant ecological upheaval. It has, however, been suggested that these events merely involved intensification of background extinction rates rather than significant shifts in the macroevolutionary regime and extinction selectivity. Here, we apply a multivariate modelling approach to a vast global database of marine organisms to test whether extinction selectivity varied through the Late Triassic and Early Jurassic. We show that these hyperthermals do represent shifts in the macroevolutionary regime and record different extinction selectivity compared to background intervals of the Late Triassic and Early Jurassic. The Late Triassic mass extinction represents a more profound change in selectivity than the early Toarcian extinction but both events show a common pattern of selecting against pelagic predators and benthic photosymbiotic and suspension-feeding organisms, suggesting that these groups of organisms may be particularly vulnerable during episodes of global warming. In particular, the Late Triassic extinction represents a macroevolutionary regime change that is characterised by (i) the change in extinction selectivity between Triassic background intervals and the extinction event itself; and (ii) the differences in extinction selectivity between the Late Triassic and Early Jurassic as a whole.

Diversity and distribution of Triassic bryozoans in the aftermath of the end-Permian mass extinction

2008 ◽  
Vol 82 (2) ◽  
pp. 362-371 ◽  
Author(s):  
Catherine M. Powers ◽  
Joseph F. Pachut
Keyword(s):  
Surface Area ◽  
Mass Extinction ◽  
Carbonate Rock ◽  
Middle Triassic ◽  
Late Triassic ◽  
Early Triassic ◽  
Diversity Pattern ◽  
Extinction Rates ◽  
Permian Mass Extinction ◽  
Early Late

Seventy-three species of stenolaemate bryozoans are documented worldwide from the Triassic. Stage-level diversity and paleogeographical analyses reveal that the recovery of bryozoans following the end-Permian mass extinction was delayed until the Middle Triassic. Early Triassic bryozoans faunas, dominated by members of the Order Trepostomida, were depauperate and geographically restricted. Bryozoan diversity increased during the Middle Triassic and diversity peaked in the Carnian (early Late Triassic). High extinction rates throughout the Late Triassic led to the extinction of all stenolaemate orders except the Cyclostomida by the end of the Triassic. Comparisons between global carbonate rock volume, outcrop surface area, and bryozoan diversity indicate that the documented diversity pattern for bryozoans may have been related, in part, to the availability of carbonate environments during the Triassic.

scholarly journals Current extinction rate in European freshwater gastropods greatly exceeds that of the late Cretaceous mass extinction

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Thomas A. Neubauer ◽  
Torsten Hauffe ◽  
Daniele Silvestro ◽  
Jens Schauer ◽  
Dietrich Kadolsky ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Recovery Period ◽  
Freshwater Ecosystems ◽  
Extinction Rate ◽  
Freshwater Gastropods ◽  
Extinction Rates ◽  
Freshwater Biota ◽  
Order Of Magnitude ◽  
To Come ◽  
Mass Extinction Event

AbstractThe Cretaceous–Paleogene mass extinction event 66 million years ago eradicated three quarters of marine and terrestrial species globally. However, previous studies based on vertebrates suggest that freshwater biota were much less affected. Here we assemble a time series of European freshwater gastropod species occurrences and inferred extinction rates covering the past 200 million years. We find that extinction rates increased by more than one order of magnitude during the Cretaceous–Paleogene mass extinction, which resulted in the extinction of 92.5% of all species. The extinction phase lasted 5.4 million years and was followed by a recovery period of 6.9 million years. However, present extinction rates in European freshwater gastropods are three orders of magnitude higher than even these revised estimates for the Cretaceous–Paleogene mass extinction. Our results indicate that, unless substantial conservation effort is directed to freshwater ecosystems, the present extinction crisis will have a severe impact to freshwater biota for millions of years to come.

Calculation of Predictive Odds for Possible Carriers of Haemophilia

1975 ◽  
Author(s):  
G. D. Forbes ◽  
A. D. McLaren ◽  
C. R. M. Prentice
Keyword(s):  
Biological Activity ◽  
Discriminant Analysis ◽  
Factor Viii ◽  
Factor Vii ◽  
Control Group ◽  
Posterior Odds ◽  
Linear Discriminant ◽  
Bayesian Calculation ◽  
Using Data ◽  
Betting Odds

The predictive odds for possible carriers of haemophilia have been calculated using data derived from normal and known carrier populations. For each individual the concentration of factor VII-related antigen (A) and factor VIII biological activity (B) was measured. The data has been studied by linear discriminant analysis linked to a Bayesian calculation of posterior odds using the predictive distributions of both the normal and obligatory carrier populations. The proportion of possible carriers assigned to the definite carrier group or control group is dependent on which betting odds are regarded as most suitable for counselling patients. For instance, if betting odds of 5 : 1 were given it was possible to assign 22 of 32 possible carriers (69 per cent) to control or carrier groups. Of this group of 22 possible carriers, 11 were thought to be normal and 11 were thought to be haemophilia carriers.

scholarly journals Anatomy of an extinction revealed by molecular fossils spanning OAE2

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. M. Forkner ◽  
J. Dahl ◽  
A. Fildani ◽  
S. M. Barbanti ◽  
I. A. Yurchenko ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Cumulative Effect ◽  
Environmental Stresses ◽  
Ecological Change ◽  
Western Interior Seaway ◽  
Oceanic Anoxic Event ◽  
Greenhorn Formation ◽  
Productivity Decline ◽  
Marine Productivity ◽  
New Evidence

AbstractThe Cenomanian–Turonian mass extinction (Oceanic Anoxic Event 2-OAE2) was a period of profound ecological change that is recorded in the sedimentary record in many locations around the globe. In this study, we provide a new and detailed account of repetitive changes in water column ecology by analyzing the organic geochemical record preserved within the OAE2 section of the Greenhorn Formation, Western Interior Seaway (WIS) of North America. Results from this study provide evidence that OAE2 in the WIS was the result of the cumulative effect of reoccurring environmental stresses rather than a single massive event. During OAE2, extreme variations in biotic composition occurred erratically over periods of several thousands of years as revealed by molecular fossil (biomarker) abundances and distributions calibrated to sedimentation rates. These cycles of marine productivity decline almost certainly had follow-on effects through the ecosystem and likely contributed to the Cenomanian–Turonian mass extinction. While the causes behind organic productivity cycling are yet unproven, we postulate that they may have been linked to repeated episodes of volcanic activity. Catastrophic volcanism and related CO2 outgassing have been interpreted as main drivers for OAE2, though this study provides new evidence that repetitive, punctuated environmental stresses were also important episodes within the anatomy of OAE2. Following OAE2, these cycles of productivity decline disappeared, and the WIS returned to conditions comparable to pre-OAE2 levels.

Carboniferous-Triassic gastropod diversity patterns and the Permo-Triassic mass extinction

Paleobiology ◽  
1990 ◽  
Vol 16 (2) ◽  
pp. 187-203 ◽  
Author(s):  
Douglas H. Erwin
Keyword(s):  
Mass Extinction ◽  
Detrended Correspondence Analysis ◽  
Taxonomic Composition ◽  
Late Paleozoic ◽  
Lower Permian ◽  
Two Phase ◽  
Environmental Distribution ◽  
Extinction Rates ◽  
History Of ◽  
Permian Mass Extinction

Paleozoic and post-Paleozoic marine faunas are strikingly different in composition. Paleozoic marine gastropods may be divided into archaic and modern groups based on taxonomic composition, ecological role, and morphology. Paleozoic assemblages were dominated by pleurotomariids (Eotomariidae and Phymatopleuridae), the Pseudozygopleuridae, and, to a lesser extent, the Euomphalidae, while Triassic assemblages were dominated by the Trochiina, Amberleyacea, and new groups of Loxonematoidea and Pleurotomariina. Several new groups of caenogastropods appeared as well. Yet the importance of the end-Permian mass extinction in generating these changes has been questioned. As part of a study of the diversity history of upper Paleozoic and Triassic gastropods, to test the extent to which taxonomic and morphologic trends established in the late Paleozoic are continued after the extinction, and to determine the patterns of selectivity operating during the extinction, I assembled generic and morphologic diversity data for 396 genera in 75 families from the Famennian through the Norian stages. Within this interval, gastropod genera underwent an adaptive radiation during the Visean and Namurian, largely of pleurotomariids, a subsequent period of dynamic stability through the Leonardian, a broad-based decline during the end-Permian mass extinction, and a two-phase post-extinction rebound during the Triassic. The patterns of generic diversity within superfamily-level clades were analyzed using Q-mode factor analysis and detrended correspondence analysis.The results demonstrate that taxonomic affinity, previous clade history, generic age, and gross morphology did not determine survival probability of genera during the end-Permian extinction, with the exception of the bellerophontids, nor did increasing diversity within clades or expansion of particular morphologies prior to the extinction facilitate survival during the extinction or success after it. The pleurotomariids diversified during the Lower Permian, but were heavily hit by the extinction. Similarly, trochiform and turriculate morphologies, among those which Vermeij (1987) has identified as having increased predation resistance, were expanding in the late Paleozoic, but suffered similar extinction rates to other nondiversifying clades. Survival was a consequence of broad geographic and environmental distribution, as was the case during background periods.

scholarly journals An unusual archosauriform tooth increases known tetrapod diversity in the lower Chinle Formation (Late Triassic) of southeastern Utah

2015 ◽  
Author(s):  
Andres Lopez ◽  
Isabella St. Aude ◽  
David Alderete ◽  
David Alvarez ◽  
Hannah Aultman ◽  
...  
Keyword(s):  
Late Triassic ◽  
Chinle Formation ◽  
Triassic Period ◽  
Using Data

An unusual tetrapod tooth was discovered in the Late Triassic Chinle Formation of southeastern Utah. The tooth was originally thought to belong to Revueltosaurus but further investigations have rejected that hypothesis. In this paper we compare MNA V10668 to other known fossil teeth found in the Chinle Formation and identify the least inclusive clade it may belongs to. Using data found in other publications and pictures of other teeth, we compare this specimen to other Triassic dental taxa. MNA V10668 shares some similarities with Crosbysaurus, Tecovasaurus, and several other named taxa but possesses unique characteristics not found in other diapsid teeth. We conclude that it is most likely an archosauromorph and probably an archosauriform. This increases the known diversity of tetrapods from the Chinle Formation and represents the first tooth morphotype completely unique to Utah in the Late Triassic Period.

Sign in / Sign up

Export Citation Format

Share Document