scholarly journals Evidence for fungal proliferation following the Cretaceous/Paleogene mass-extinction event, based on chemostratigraphy in the Raton and Powder River basins, western North America

2020 ◽  
pp. 134-142
Author(s):  
Keith Berry
Keyword(s):  
Amino Acid ◽  
North America ◽  
Mass Extinction ◽  
River Basins ◽  
High Energy ◽  
Western North America ◽  
Ecosystem Recovery ◽  
Extinction Event ◽  
Mass Extinction Event ◽  
The Impact

The presence of the amino acid α-aminoisobutyric acid (Aib) within Cretaceous/Paleogene (K/Pg) boundary clay in the Raton and Powder River basins in Colorado and Wyoming, respectively, has been described as compelling evidence that extraterrestrial Aib survived the high-energy Chicxulub impact. Based on contemporary experiments and simulations, however, it is highly unlikely that extraterrestrial Aib survived the impact, which had peak impact pressures and temperatures in excess of 600 GPa and 10,000 K, respectively. In other words, the amino acid signature of the carbonaceous chondritic asteroid that impacted Chicxulub was undoubtedly destroyed upon impact during formation of the vapor plume or so-called “fireball.” The only organisms known to produce Aib are the suite (more than 30 genera) of cosmopolitan saprotrophic filamentous fungi that include Trichoderma Pers., which has recently been hypothesized to have thrived during the K/Pg mass-extinction event. Therefore it is proposed that the Aib horizon in the K/Pg boundary clay in the Raton and Powder River basins correlates with the K/Pg boundary fungal spike, which thus far has only been observed in New Zealand (Southern Hemisphere). This proposition is based upon superimposing the Aib horizon on the well-known iridium and fern-spore spikes, as its stratigraphic position precisely matches that predicted by the fungal spike. If correct, this hypothesis alters the conventional perspective on the tempo and mode of terrestrial ecosystem recovery in western North America, as the heavily sampled K/Pg boundary section in the Raton Basin was instrumental in shaping the traditional narrative of the rapid recolonization of a denuded landscape by ferns via wind-blown spores in the immediate wake of regional deforestation caused by the K/Pg impact event. Perhaps more importantly, it could present an alternative to traditional palynological approaches for locating the fungal spike in other terrestrial K/Pg boundary sections and could provide additional support for the generalization that global mass-extinction events are frequently accompanied by fungal spikes.

scholarly journals The impact of the Cretaceous–Paleogene (K–Pg) mass extinction event on the global sulfur cycle: Evidence from Seymour Island, Antarctica

2018 ◽  
Vol 230 ◽  
pp. 17-45 ◽  
Author(s):  
James D. Witts ◽  
Robert J. Newton ◽  
Benjamin J.W. Mills ◽  
Paul B. Wignall ◽  
Simon H. Bottrell ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Sulfur Cycle ◽  
Extinction Event ◽  
Mass Extinction Event ◽  
The Impact ◽  
Seymour Island

scholarly journals A Hiatus Obscures the Early Evolution of Modern Lineages of Bony Fishes

2021 ◽  
Vol 8 ◽  
Author(s):  
Carlo Romano
Keyword(s):  
Mass Extinction ◽  
Fossil Record ◽  
Middle Triassic ◽  
Early Evolution ◽  
Early Triassic ◽  
Triassic Boundary ◽  
Bony Fishes ◽  
Extinction Event ◽  
Mass Extinction Event ◽  
The Impact

About half of all vertebrate species today are ray-finned fishes (Actinopterygii), and nearly all of them belong to the Neopterygii (modern ray-fins). The oldest unequivocal neopterygian fossils are known from the Early Triassic. They appear during a time when global fish faunas consisted of mostly cosmopolitan taxa, and contemporary bony fishes belonged mainly to non-neopterygian (“paleopterygian”) lineages. In the Middle Triassic (Pelsonian substage and later), less than 10 myrs (million years) after the Permian-Triassic boundary mass extinction event (PTBME), neopterygians were already species-rich and trophically diverse, and bony fish faunas were more regionally differentiated compared to the Early Triassic. Still little is known about the early evolution of neopterygians leading up to this first diversity peak. A major factor limiting our understanding of this “Triassic revolution” is an interval marked by a very poor fossil record, overlapping with the Spathian (late Olenekian, Early Triassic), Aegean (Early Anisian, Middle Triassic), and Bithynian (early Middle Anisian) substages. Here, I review the fossil record of Early and Middle Triassic marine bony fishes (Actinistia and Actinopterygii) at the substage-level in order to evaluate the impact of this hiatus–named herein the Spathian–Bithynian gap (SBG)–on our understanding of their diversification after the largest mass extinction event of the past. I propose three hypotheses: 1) the SSBE hypothesis, suggesting that most of the Middle Triassic diversity appeared in the aftermath of the Smithian-Spathian boundary extinction (SSBE; ∼2 myrs after the PTBME), 2) the Pelsonian explosion hypothesis, which states that most of the Middle Triassic ichthyodiversity is the result of a radiation event in the Pelsonian, and 3) the gradual replacement hypothesis, i.e. that the faunal turnover during the SBG was steady and bony fishes were not affected by extinction events subsequent to the PTBME. Based on current knowledge, hypothesis three is favored herein, but further studies are necessary to test alternative hypotheses. In light of the SBG, claims of a protracted diversification of bony fishes after the PTBME should be treated with caution.

A systematic reappraisal and quantitative study of the non-marine teleost fishes from the late Maastrichtian of the Western Interior of North America – evidence from vertebrate microfossil localities

2020 ◽  
Author(s):  
Donald B. Brinkman ◽  
Julien Divay ◽  
David Gerard DeMar ◽  
Gregory P. Wilson Mantilla
Keyword(s):  
North America ◽  
Quantitative Study ◽  
Mass Extinction ◽  
Early Eocene ◽  
Teleost Fishes ◽  
Marine Teleost ◽  
Hell Creek Formation ◽  
Extinction Event ◽  
Relative Abundances ◽  
Mass Extinction Event

The diversity and distribution of non-marine teleost fishes in the Western Interior of North America during the late Maastrichtian is documented based on isolated elements from vertebrate microfossil localities in the Hell Creek Formation of Montana, the Lance Formation of Wyoming, and the Scollard Formation of Alberta. A minimum of 20 taxa are recognized based on >1900 abdominal centra and tooth-bearing elements. These include two elopomorphs, six osteoglossomorphs, three ostariophysans, one esocid, six acanthomorphs, and two taxa of unknown relationships. These assemblages differ from late Campanian assemblages in the absence of the Clupeomorpha and the presence of the Perciformes. Within the Hell Creek Formation, we record patterns in the relative abundances of the most abundant taxa leading up to the Cretaceous/Paleogene (K/Pg) boundary. Most notably, acanthomorphs increased in abundance up-section whereas a group of osteoglossomorphs represented by Coriops and/or Lopadichthys concurrently decreased in abundance. Conversely, some teleosts exhibited more stable or slightly fluctuating relative abundances through the formation (Wilsonichthyidae, Esocidae). These late Maastrichtian teleost assemblages are of higher diversity than an early Eocene assemblage from Wyoming that is preserved under similar taphonomic conditions. This pattern either suggests that lower Cenozoic deposits in the Western Interior are insufficiently sampled or that the K/Pg mass extinction event adversely affected non-marine teleosts.

scholarly journals Fern spore viability considered in relation to the duration of the Cretaceous-Paleogene (K-Pg) impact winter. A contribution to the discussion

2019 ◽  
Vol 59 (1) ◽  
pp. 19-25 ◽  
Author(s):  
Keith Berry
Keyword(s):  
New Mexico ◽  
Soil Seed Bank ◽  
Western North America ◽  
Short Term ◽  
Spore Viability ◽  
Depositional Settings ◽  
Extinction Event ◽  
Mass Extinction Event ◽  
Chicxulub Impact ◽  
The Impact

Abstract The Cretaceous-Paleogene (K-Pg) boundary Chicxulub impact is supposed to have produced a nearly decade-long impact winter which resulted in a mass-extinction event among dicot angiosperms but which left pteridophytes comparatively unaffected. Dicot angiosperms subsequently recovered from the soil seed bank following an episode of global deforestation, although this recovery took centuries. Pteridophytes, on the other hand, are supposed to have recovered within months of the impact event, due to the characteristic, short-term viability of fern spores in the soil bank – an interpretation consistent with the assumption that the dominant fern spore at the K-Pg boundary fern spore spike, Cyathidites Couper, was produced by cyatheaceous foliage. At the K-Pg boundary section near Sugarite, New Mexico, however, Cyathidites spores are more likely to have been produced by schizaeaceous foliage, which produces spores capable of germinating after spending about a decade or more in the soil and which already commanded similar depositional settings in western North America during the Maastrichtian. Therefore, the protracted – millennial – timescale for fern dominance in the earliest Danian could be related to the unique ecology of schizaeaceous ferns that recovered from a persistent spore bank in a habitat that they already dominated, presumably by suppressing the colonization of angiosperms.

scholarly journals Impact of K-Pg Mass Extinction Event on Crocodylomorpha Inferred from Phylogeny of Extinct and Extant Taxa

2021 ◽  
Author(s):  
Andrew F. Magee ◽  
Sebastian Höhna
Keyword(s):  
Mass Extinction ◽  
Likelihood Function ◽  
Simulated Data ◽  
Mass Extinctions ◽  
Holistic View ◽  
Occurrence Data ◽  
Extinction Event ◽  
Mass Extinction Event ◽  
Biodiversity Changes ◽  
The Impact

AbstractCrocodilians and their allies have survived several mass extinction events. However, the impact of the K-Pg mass extinction event on crocodylomorphs is considered as minor or non-existent although other clades of archosaurs, e.g., non-avian dinosaurs and pterosaurs, went extinct completely. Previous approaches using fossil occurrence data alone have proven inconclusive. In this paper, we take a phylogenetic approach using extant and extinct species. The time-calibrated phylogeny of extant crocodilians provides insights into the pattern of recent biodiversity changes whereas fossil occurrence data provide insights about the more ancient past. The two data sources combined into a single phylogeny with extinct and extant taxa provide a holistic view of the historical biodiversity. To utilize this combined data and to infer the impact of the K-Pg mass extinction event, we derive the likelihood function for a time-varying (episodic) serially sampled birth-death model that additionally incorporates mass extinctions and bursts of births. We implemented the likelihood function in a Bayesian framework with recently developed smoothing priors to accommodate for both abrupt and gradual changes in speciation, extinction and fossilization rates. Contrary to previous research, we find strong evidence for the K-Pg extinction event in crocodiles and their allies. This signal is robust to uncertainty in the phylogeny and the prior on the mass extinctions. Through simulated data analyses, we show that there is high power to detect this mass extinction and little risk of false positives.

Chicxulub Structure: A Volcanic Sequence of Late Cretaceous Age

1994 ◽  
Vol 7 ◽  
pp. 425-436
Author(s):  
Charles B. Officer
Keyword(s):  
New Zealand ◽  
Residence Time ◽  
Late Cretaceous ◽  
Food Chain ◽  
Mass Extinction ◽  
Dust Cloud ◽  
Asteroid Impact ◽  
Extinction Event ◽  
Mass Extinction Event ◽  
The Impact

The present Cretaceous/Tertiary extinction debate started with findings by Alvarez et al. (1980) of enhanced levels of iridium at K/T sections in Italy, Denmark and New Zealand. They postulated that the iridium was extraterrestrial in origin and related to a 10 km diameter asteroid impact which would have produced a crater some 200 km in diameter. They further suggested that a giant dust cloud would have been injected into the stratosphere from the impact with a residence time of several years and that the resulting darkness would have suppressed photosynthesis with a consequent elimination of succeeding members in the biological food chain — ergo, a mass extinction event.

Rapid macrobenthic diversification and stabilization after the end-Cretaceous mass extinction event

Geology ◽  
2020 ◽  
Vol 48 (11) ◽  
pp. 1048-1052
Author(s):  
Francisco J. Rodríguez-Tovar ◽  
Christopher M. Lowery ◽  
Timothy J. Bralower ◽  
Sean P.S. Gulick ◽  
Heather L. Jones
Keyword(s):  
Mass Extinction ◽  
Rapid Recovery ◽  
Community Recovery ◽  
Scientific Drilling ◽  
Extinction Event ◽  
Chicxulub Impact Crater ◽  
Mass Extinction Event ◽  
International Ocean Discovery Program ◽  
Extinction Events ◽  
The Impact

Abstract Previous ichnological analysis at the Chicxulub impact crater, Yucatán Peninsula, México (International Ocean Discovery Program [IODP]/International Continental Scientific Drilling Program [ICDP] Site M0077), showed a surprisingly rapid initial tracemaker community recovery after the end-Cretaceous (Cretaceous-Paleogene [K-Pg]) mass extinction event. Here, we found that full recovery was also rapid, with the establishment of a well-developed tiered community within ∼700 k.y. Several stages of recovery were observed, with distinct phases of stabilization and diversification, ending in the development of a trace fossil assemblage mainly consisting of abundant Zoophycos, Chondrites, and Planolites, assigned to the Zoophycos ichnofacies. The increase in diversity is associated with higher abundance, larger forms, and a deeper and more complex tiering structure. Such rapid recovery suggests that favorable paleoenvironmental conditions were quickly reestablished within the impact basin, enabling colonization of the substrate. Comparison with the end-Permian extinction reveals similarities during recovery, yet postextinction recovery was significantly faster after the K-Pg event. The rapid recovery has significant implications for the evolution of macrobenthic biota after the K-Pg event. Our results have relevance in understanding how communities recovered after the K-Pg impact and how this event differed from other mass extinction events.

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