scholarly journals Preliminary bone histological analysis of Lystrosaurus (Therapsida: Dicynodontia) from the Lower Triassic of North China, and its implication for lifestyle and environments after the end-Permian extinction

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248681
Author(s):  
Fenglu Han ◽  
Qi Zhao ◽  
Jun Liu
Keyword(s):  
South Africa ◽  
Bone Tissue ◽  
Lower Triassic ◽  
Early Ontogeny ◽  
Growth Strategy ◽  
Bone Histology ◽  
Early Triassic ◽  
Tissue Changes ◽  
Permian Extinction ◽  
Permian Mass Extinction

Lystrosaurus represents one of the most successful dicynodonts, a survivor of the end-Permian mass extinction that remained abundant in the Early Triassic, but many aspects of its paleobiology are still controversial. The bone histology of Lystrosaurus species from South Africa and India has provided important information on their growth strategy and lifestyle, but until recently no data was available on the bone histology of Lystrosaurus from China. Here, we report on the bone microstructure of seven Lystrosaurus individuals from the Lower Triassic of Xinjiang, providing the first such data for the Chinese Lystrosaurus species. Our samples indicate that the microstructure of Lystrosaurus limb bones from China is characterized by fibrolamellar bone tissue similar to those from South Africa and India. Three ontogenetic stages were identified: juvenile, early subadult, and late subadult based on lines of arrested growth (LAGs) and bone tissue changes. Bone histology supports a rapid growth strategy for Lystrosaurus during early ontogeny. Unlike Early Triassic Lystrosaurus from South Africa, lines of arrested growth are common in our specimens, suggesting that many individuals of Chinese Lystrosaurus had reached the subadult stage and were interrupted in growth. The differences in bone histology between Lystrosaurus from South Africa and China may indicate different environmental conditions in these two regions.

scholarly journals Inter-element variation in the bone histology of Anteosaurus (Dinocephalia, Anteosauridae) from the Tapinocephalus Assemblage Zone of the Karoo Basin of South Africa

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12082
Author(s):  
Mohd Shafi Bhat ◽  
Christen D. Shelton ◽  
Anusuya Chinsamy
Keyword(s):  
South Africa ◽  
Bone Tissue ◽  
Early Ontogeny ◽  
Bone Histology ◽  
Karoo Basin ◽  
Slowing Down ◽  
Ephemeral Pools ◽  
Assemblage Zone ◽  
Histological Results ◽  
Bone Deposition

Despite its abundance in the Permian fossil record of South Africa, little is known about the life history of Anteosaurus. Here we examine the bone microstructure of multiple skeletal elements of Anteosaurus from the Tapinocephalus Assemblage Zone of the Karoo Basin. The bone histology of Anteosaurus magnificus reveals that the cortex is composed of highly vascularized, uninterrupted fibrolamellar bone tissue surrounding the inner spongy medullary region. However, the histology of two ribs and a previously described femur of another Anteosaurus taxon revealed an interrupted growth pattern with lines of arrested growth and peripheral rest lines occurring in the compacta, indicating periodic pauses in growth possibly linked to the slowing down of growth during maturity. Given that the fibula of the same individual has well-vascularised fibrolamellar bone tissue without any growth marks in the cortex; this suggests variation in skeletal growth. Based on our histological results, three growth dynamic stages are deduced for the genus Anteosaurus: (i) the earliest growth stage is represented by the predominance of highly vascularized, uninterrupted fibrolamellar bone tissue in the inner cortex, which suggests rapid periosteal bone deposition during early ontogeny; (ii) the next stage of growth shows periodic interruptions in the bone deposition as indicated by the deposition of lines of arrested growth; (iii) the third stage shows the development of lamellar bone tissue with rest lines in the peripheral part of the cortex suggesting a slowing down of growth prior to death. Most of the skeletal elements are characterized by thick bone walls, extensive secondary reconstruction and the complete infilling of the medullary cavity. However, the radius and a previously studied femur have open medullary cavities with struts of bony trabeculae. Based on histologic structures and comparisons with extant taxa, it is likely that Anteosaurus may have been more terrestrial as its osteology point towards terrestriality, but it may have occasionally inhabited ephemeral pools like modern semi-aquatic Hippopotamus.

scholarly journals Crinoids from Svalbard in the aftermath of the end−Permian mass extinction

2015 ◽  
Vol 36 (3) ◽  
pp. 225-238 ◽  
Author(s):  
Mariusz A. Salamon ◽  
Przemysław Gorzelak ◽  
Nils−Martin Hanken ◽  
Henrik Erevik Riise ◽  
Bruno Ferré
Keyword(s):  
Mass Extinction ◽  
Lower Triassic ◽  
Late Paleozoic ◽  
Early Triassic ◽  
Major Event ◽  
Early Mesozoic ◽  
History Of ◽  
Permian Extinction ◽  
Stratigraphic Ranges ◽  
Permian Mass Extinction

AbstractThe end-Permian mass extinction constituted a major event in the history of crinoids. It led to the demise of the major Paleozoic crinoid groups including cladids, disparids, flexibles and camerates. It is widely accepted that a single lineage, derived from a late Paleozoic cladid ancestor (Ampelocrinidae), survived this mass extinction. Holocrinid crinoids (Holocrinus, Holocrinida) along with recently described genus Baudicrinus (Encrinida), the only crinoid groups known from the Early Triassic, are considered the stem groups for the post-Paleozoic monophyletic subclass Articulata. Here, we report preliminary data on unexpectedly diverse crinoid faunas comprising at least four orders from the Lower Triassic (Induan and Olenekian) of Svalbard, extending their stratigraphic ranges deeper into the early Mesozoic. These findings strongly imply that the recovery of crinoids in the aftermath of the end-Permian extinction began much earlier at higher palaeolatitudes than in the central Tethys.

The postcranial skeleton, phylogenetic position, and probable lifestyle of the Early Triassic reptile Procolophon trigoniceps

2003 ◽  
Vol 40 (4) ◽  
pp. 527-556 ◽  
Author(s):  
Michael deBraga
Keyword(s):  
South Africa ◽  
Morphological Study ◽  
Lower Triassic ◽  
Sister Group ◽  
Phylogenetic Position ◽  
Sister Group Relationship ◽  
Early Triassic ◽  
Postcranial Skeleton ◽  
Sister Clade ◽  
Key Innovations

A morphological study of the postcranial skeleton of Procolophon trigoniceps from the Lower Triassic of South Africa and Antarctica is undertaken. Procolophon shares a sister-group relationship with the procolophonid Tichvinskia from the Lower Triassic of Russia and is a basal member of Procolophonidae. This clade also includes the enigmatic taxon Sclerosaurus, believed most recently to be a pareiasaur relative. Owenettids form a separate lineage from Procolophonidae and are predominantly restricted to the Permian of both South Africa and Madagascar. A phylogenetically based assessment is considered, in which specialized modern taxa (sand lizards) are compared to their nonfossorial sister clade, allowing for "key innovations" to be identified. A similar comparison between owenettids and procolophonids reveals a number of apparent "key innovations" within procolophonids that are suggestive of a burrowing lifestyle for Procolophon.

A new faunistic component of the Lower Triassic Panchet Formation of India increases the continental non-archosauromorph neodiapsid record in the aftermath of the end-Permian mass extinction

2021 ◽  
pp. 1-11
Author(s):  
Martín D. Ezcurra ◽  
Saswati Bandyopadhyay ◽  
Kasturi Sen
Keyword(s):  
Mass Extinction ◽  
Lower Triassic ◽  
Maximum Height ◽  
Dorsal Margin ◽  
Early Triassic ◽  
Anterior Portion ◽  
Continental Deposits ◽  
Biotic Recovery ◽  
Patterns And Processes ◽  
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.

scholarly journals Echinoids from the Tesero Member (Werfen Formation) of the Dolomites (Italy): implications for extinction and survival of echinoids in the aftermath of the end-Permian mass extinction

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7361
Author(s):  
Jeffrey R. Thompson ◽  
Renato Posenato ◽  
David J. Bottjer ◽  
Elizabeth Petsios
Keyword(s):  
Mass Extinction ◽  
Sea Urchins ◽  
Northern Italy ◽  
Early Triassic ◽  
Crown Group ◽  
Stem Group ◽  
Extinction Event ◽  
Permian Extinction ◽  
Permian Mass Extinction ◽  
A New Species

The end-Permian mass extinction (∼252 Ma) was responsible for high rates of extinction and evolutionary bottlenecks in a number of animal groups. Echinoids, or sea urchins, were no exception, and the Permian to Triassic represents one of the most significant intervals of time in their macroevolutionary history. The extinction event was responsible for significant turnover, with the Permian–Triassic representing the transition from stem group echinoid-dominated faunas in the Palaeozoic to Mesozoic faunas dominated by crown group echinoids. This turnover is well-known, however, the environmental and taxonomic distribution of echinoids during the latest Permian and Early Triassic is not. Here we report on an echinoid fauna from the Tesero Member, Werfen Formation (latest Permian to Early Triassic) of the Dolomites (northern Italy). The fauna is largely known from disarticulated ossicles, but consists of both stem group taxa, and a new species of crown group echinoid,Eotiaris teseroensisn. sp. That these stem group echinoids were present in the Tesero Member indicates that stem group echinoids did not go extinct in the Dolomites coincident with the onset of extinction, further supporting other recent work indicating that stem group echinoids survived the end-Permian extinction. Furthermore, the presence ofEotiarisacross a number of differing palaeoenvironments in the Early Triassic may have had implications for the survival of cidaroid echinoids during the extinction event.

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

PeerJ ◽  
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.

scholarly journals The Disaster Taxon Lystrosaurus: A Paleontological Myth

2020 ◽  
Vol 8 ◽  
Author(s):  
Sean P. Modesto
Keyword(s):  
South Africa ◽  
Mass Extinction ◽  
Lower Triassic ◽  
Opportunistic Species ◽  
Phylogenetic Studies ◽  
Extinction Event ◽  
Tree Topologies ◽  
Mass Extinction Event ◽  
Permian Mass Extinction ◽  
Survival Interval

The term “disaster species” was a term originally conceived to describe marine microfossils that exhibited profound abundances in the wake of a biological crisis. The term was expanded in the 1990s to describe (as “disaster taxa”) opportunistic taxa that dominated their biota numerically (“bloomed”) during the survival interval of a mass extinction event. The Permo-Triassic tetrapod genus Lystrosaurus has been cited regularly as a “disaster taxon” of the end-Permian mass extinction. A review of the definitions that have been developed for disaster taxa, and data from recent biostratigraphic and phylogenetic studies that include species of Lystrosaurus, leads to the conclusion that the genus is not a “disaster taxon”. Further, the known biostratigraphy and tree topologies of species of Lystrosaurus do not satisfy more recent definitions that attribute diversification to disaster species. At most, species of Lystrosaurus that form the informal “Lystrosaurus abundant zone” in the lower Katberg Formation, Lower Triassic of South Africa, could be described as opportunistic species.

Implications of giant ooids for the carbonate chemistry of Early Triassic seawater

Geology ◽  
2020 ◽  
Author(s):  
Xiaowei Li ◽  
Elizabeth J. Trower ◽  
Daniel J. Lehrmann ◽  
Marcello Minzoni ◽  
Brian M. Kelley ◽  
...  
Keyword(s):  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Lower Triassic ◽  
Early Triassic ◽  
Formation Model ◽  
Carbonate Chemistry ◽  
Saturation State ◽  
Seawater Chemistry ◽  
Model Calculations ◽  
Permian Mass Extinction

Lower Triassic limestones contain giant ooids (>2 mm) along with other precipitated carbonate textures more typical of Precambrian strata. These features appear to have resulted from changes in seawater chemistry associated with the end-Permian mass extinction, but quantifying the carbonate chemistry of Early Triassic seawater has remained challenging. To constrain seawater carbonate saturation state, dissolved inorganic carbon, alkalinity, and pH, we applied a physicochemical model of ooid formation constrained by new size data on Lower Triassic ooids from south China, finding that the Triassic giant ooids require a higher carbonate saturation state than typifies modern sites of ooid formation. Model calculations indicate that Early Triassic oceans were at least seven times supersaturated with respect to aragonite and calcite. When combined with independent constraints on atmospheric pCO2 and oceanic [Ca2+], these findings require that Early Triassic oceans had more than twice the modern levels of dissolved inorganic carbon and alkalinity and a pH near 7.6. Such conditions may have played a role in inhibiting the recovery of skeletal animals and algae during Early Triassic time.

scholarly journals Marine anoxia and delayed Earth system recovery after the end-Permian extinction

2016 ◽  
Vol 113 (9) ◽  
pp. 2360-2365 ◽  
Author(s):  
Kimberly V. Lau ◽  
Kate Maher ◽  
Demir Altiner ◽  
Brian M. Kelley ◽  
Lee R. Kump ◽  
...  
Keyword(s):  
Marine Ecosystem ◽  
Biogeochemical Cycles ◽  
Upper Permian ◽  
Ecosystem Structure ◽  
Early Triassic ◽  
Earth System ◽  
Marine Animals ◽  
Animal Diversity ◽  
Permian Extinction ◽  
Permian Mass Extinction

Delayed Earth system recovery following the end-Permian mass extinction is often attributed to severe ocean anoxia. However, the extent and duration of Early Triassic anoxia remains poorly constrained. Here we use paired records of uranium concentrations ([U]) and 238U/235U isotopic compositions (δ238U) of Upper Permian−Upper Triassic marine limestones from China and Turkey to quantify variations in global seafloor redox conditions. We observe abrupt decreases in [U] and δ238U across the end-Permian extinction horizon, from ∼3 ppm and −0.15‰ to ∼0.3 ppm and −0.77‰, followed by a gradual return to preextinction values over the subsequent 5 million years. These trends imply a factor of 100 increase in the extent of seafloor anoxia and suggest the presence of a shallow oxygen minimum zone (OMZ) that inhibited the recovery of benthic animal diversity and marine ecosystem function. We hypothesize that in the Early Triassic oceans—characterized by prolonged shallow anoxia that may have impinged onto continental shelves—global biogeochemical cycles and marine ecosystem structure became more sensitive to variation in the position of the OMZ. Under this hypothesis, the Middle Triassic decline in bottom water anoxia, stabilization of biogeochemical cycles, and diversification of marine animals together reflect the development of a deeper and less extensive OMZ, which regulated Earth system recovery following the end-Permian catastrophe.

FAST RADIATION OF EARLY TRIASSIC MARINE REPTILES IN THE WAKE OF THE END-PERMIAN EXTINCTION

2017 ◽  
Author(s):  
Da-yong Jiang ◽  
◽  
Ryosuke Motani ◽  
Andrea Tintori ◽  
Zuoyu Sun ◽  
...  
Keyword(s):  
Early Triassic ◽  
Marine Reptiles ◽  
Permian Extinction
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