The elemental geochemistry of Lower Triassic shallow-marine carbonates from central Saudi Arabia: Implications for redox conditions in the immediate aftermath of the latest Permian mass extinction

Abstract The fossil record of Early Triassic diapsids is very important to understand how the end-Permian mass extinction affected ecosystems and the patterns and processes involved in the subsequent biotic recovery. Vertebrate fossil assemblages of continental deposits in current-day South Africa, China, and Russia are the best source of information of this clade during the aftermath of the extinction event. Although considerably less sampled, the Induan continental rocks of the Panchet Formation of the Damodar Basin (eastern India) have also yielded a relatively diverse vertebrate assemblage composed of fishes, temnospondyls, synapsids, and a single proterosuchid taxon. Here, we report on a small isolated diapsid partial ilium (ISIR 1132) from the upper Panchet Formation. This specimen has a distinct morphology compared to other tetrapods that we know, including a shallow emargination on the dorsal margin of the anterior portion of the iliac blade, and ratio between height of iliac blade versus maximum height of iliac acetabulum at level of the dorsalmost extension of supraacetabular crest ≤0.45. Comparisons and a quantitative phylogenetic analysis found ISIR 1132 as a non-archosauromorph neodiapsid. This new specimen expands the reptile diversity in the Panchet Formation as well as for the rest of Gondwana, where Early Triassic non-archosauromorph neodiapsid species are extremely scarce.

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PROLIFERATION OF MISS-RELATED MICROBIAL MATS FOLLOWING THE END-PERMIAN MASS EXTINCTION: EVIDENCE FROM THE LOWER TRIASSIC OF THE YIYANG AREA, NORTH CHINA

10.1130/abs/2016am-278019 ◽

2016 ◽

Author(s):

Chenyi Tu ◽

◽

Zhong Qiang Chen ◽

Gregory J. Retallack ◽

Yuangeng Huang ◽

...

Keyword(s):

Mass Extinction ◽

North China ◽

Microbial Mats ◽

Lower Triassic ◽

Area North ◽

Permian Mass Extinction

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Archosauriform footprints in the Lower Triassic of Western Alps and their role in understanding the effects of the Permian-Triassic hyperthermal

PeerJ ◽

10.7717/peerj.10522 ◽

2020 ◽

Vol 8 ◽

pp. e10522

Author(s):

Fabio Massimo Petti ◽

Heinz Furrer ◽

Enrico Collo ◽

Edoardo Martinetto ◽

Massimo Bernardi ◽

...

Keyword(s):

Mass Extinction ◽

Lower Triassic ◽

Western Alps ◽

Large Igneous Province ◽

Early Triassic ◽

Triassic Boundary ◽

Habitable Zones ◽

Single Well ◽

Permian Mass Extinction ◽

Permian Triassic Boundary

The most accepted killing model for the Permian-Triassic mass extinction (PTME) postulates that massive volcanic eruption (i.e., the Siberian Traps Large Igneous Province) led to geologically rapid global warming, acid rain and ocean anoxia. On land, habitable zones were drastically reduced, due to the combined effects of heating, drought and acid rains. This hyperthermal had severe effects also on the paleobiogeography of several groups of organisms. Among those, the tetrapods, whose geographical distribution across the end-Permian mass extinction (EPME) was the subject of controversy in a number of recent papers. We here describe and interpret a new Early Triassic (?Olenekian) archosauriform track assemblage from the Gardetta Plateau (Briançonnais, Western Alps, Italy) which, at the Permian-Triassic boundary, was placed at about 11° North. The tracks, both arranged in trackways and documented by single, well-preserved imprints, are assigned to Isochirotherium gardettensis ichnosp. nov., and are here interpreted as produced by a non-archosaurian archosauriform (erytrosuchid?) trackmaker. This new discovery provides further evidence for the presence of archosauriformes at low latitudes during the Early Triassic epoch, supporting a model in which the PTME did not completely vacate low-latitude lands from tetrapods that therefore would have been able to cope with the extreme hot temperatures of Pangaea mainland.

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