Showing posts with label Wujiapingian. Show all posts
Showing posts with label Wujiapingian. Show all posts

Thursday, September 04, 2014

Siberian Traps may NOT have Burned Coal

Latest Permian chars may derive from wildfires, not coal combustion

Authors:

Hudspith et al

Abstract:

The Permian-Triassic boundary extinction event was the largest biological crisis of the Phanerozoic. One of the principle triggers for the mass extinction is thought to be greenhouse warming resulting from the release of CH4 from basalt-coal interaction during the extensive Siberian Traps (Russia) eruptions. Observations of organic matter interpreted to be coal combustion products (fly ash) in latest Permian marine sediments have been used to support this hypothesis. However, this interpretation is dependent upon vesicular chars being fly ash (coal combustion derived) and not formed by alternative mechanisms. Here we present reflectance microscopy images of vesicular chars from Russian Permian coals, and chars from modern tundra, peatland, and boreal forest fires, to demonstrate that despite a difference in precursor fuels, wildfires are capable of generating vesicular chars that are morphologically comparable to end-Permian fly ash. These observations, coupled with extensive global evidence of wildfires during this time interval, call into question the contribution of coal combustion to the end-Permian extinction event.

Thursday, December 05, 2013

New Statistical Analysis Suggests Environmental Degradation 1.2 Million Years Before End Permian Extinction


Quantifying the process and abruptness of the end-Permian mass extinction

Authors:

Wang et al

Abstract:

Studies of the end-Permian mass extinction have suggested a variety of patterns from a single catastrophic event to multiple phases. But most of these analyses have been based on fossil distributions from single localities. Although single sections may simplify the interpretation of species diversity, they are susceptible to bias from stratigraphic incompleteness and facies control of preservation. Here we use a data set of 1450 species from 18 fossiliferous sections in different paleoenvironmental settings across South China and the northern peri-Gondwanan region, and integrate it with high-precision geochronologic data to evaluate the rapidity of the largest Phanerozoic mass extinction. To reduce the Signor-Lipps effect, we applied constrained optimization (CONOP) to search for an optimal sequence of first and last occurrence datums for all species and generate a composite biodiversity pattern based on multiple sections. This analysis indicates that an abrupt extinction of 62% of species took place within 200 Kyr. The onset of the sudden extinction is around 252.3 Ma, just below Bed 25 at the Meishan section. Taxon turnover and diversification rates suggest a deterioration of the living conditions nearly 1.2 Myr before the sudden extinction. The magnitude of the extinction was such that there was no immediate biotic recovery. Prior suggestions of highly variable, multi-phased extinction patterns reflect the impact of the Signor-Lipps effect and facies-dependent occurrences, and are not supported following appropriate statistical treatment of this larger data set.
 

Niassodon mfumukasi: a new Dicynodont With Teeth From Wuchiapingian Permian Mozambique



Bringing Dicynodonts Back to Life: Paleobiology and Anatomy of a New Emydopoid Genus from the Upper Permian of Mozambique

Authors:

Castanhinha et al

Abstract:

Dicynodontia represent the most diverse tetrapod group during the Late Permian. They survived the Permo-Triassic extinction and are central to understanding Permo-Triassic terrestrial ecosystems. Although extensively studied, several aspects of dicynodont paleobiology such as, neuroanatomy, inner ear morphology and internal cranial anatomy remain obscure. Here we describe a new dicynodont (Therapsida, Anomodontia) from northern Mozambique: Niassodon mfumukasi gen. et sp. nov. The holotype ML1620 was collected from the Late Permian K5 formation, Metangula Graben, Niassa Province northern Mozambique, an almost completely unexplored basin and country for vertebrate paleontology. Synchrotron radiation based micro-computed tomography (SRµCT), combined with a phylogenetic analysis, demonstrates a set of characters shared with Emydopoidea. All individual bones were digitally segmented allowing a 3D visualization of each element. In addition, we reconstructed the osseous labyrinth, endocast, cranial nerves and vasculature. The brain is narrow and the cerebellum is broader than the forebrain, resembling the conservative, “reptilian-grade” morphology of other non-mammalian therapsids, but the enlarged paraflocculi occupy the same relative volume as in birds. The orientation of the horizontal semicircular canals indicates a slightly more dorsally tilted head posture than previously assumed in other dicynodonts. In addition, synchrotron data shows a secondary center of ossification in the femur. Thus ML1620 represents, to our knowledge, the oldest fossil evidence of a secondary center of ossification, pushing back the evolutionary origins of this feature. The fact that the specimen represents a new species indicates that the Late Permian tetrapod fauna of east Africa is still incompletely known.

Thursday, September 19, 2013

Late Permian Milankovitch Cycles Time Calibrated, Indicate a 22 Hour Day



Time-calibrated Milankovitch cycles for the late Permian

Authors:

1. Huaichun Wu (a,b)
2. Shihong Zhang (a)
3. Linda A. Hinnov (c)
4. Ganqing Jiang (d)
5. Qinglai Feng (e)
6. Haiyan Li (a)
7. Tianshui Yang (a)

Affiliations:

a. State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China

b. School of Ocean Sciences, China University of Geosciences, Beijing 100083, China

c. Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, Maryland 21218, USA

d. Department of Geoscience, University of Nevada, Las Vegas, Nevada 89154, USA

e. State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074, China

Abstract:

An important innovation in the geosciences is the astronomical time scale. The astronomical time scale is based on the Milankovitch-forced stratigraphy that has been calibrated to astronomical models of paleoclimate forcing; it is defined for much of Cenozoic–Mesozoic. For the Palaeozoic era, however, astronomical forcing has not been widely explored because of lack of high-precision geochronology or astronomical modelling. Here we report Milankovitch cycles from late Permian (Lopingian) strata at Meishan and Shangsi, South China, time calibrated by recent high-precision U–Pb dating. The evidence extends empirical knowledge of Earth’s astronomical parameters before 250 million years ago. Observed obliquity and precession terms support a 22-h length-of-day. The reconstructed astronomical time scale indicates a 7.793-million year duration for the Lopingian epoch, when strong 405-kyr cycles constrain astronomical modelling. This is the first significant advance in defining the Palaeozoic astronomical time scale, anchored to absolute time, bridging the Palaeozoic–Mesozoic transition.

Monday, June 24, 2013

Bunostegos: a Desert Dwelling Relic Pareiasaur From the Late Permian Niger


During the Permian era, the Earth was dominated by a single supercontinent called Pangea – "All-Earth". Animal and plant life dispersed broadly across this land, as documented by identical fossil species found on multiple modern continents. But a new study published in the Journal of Vertebrate Paleontology supports the idea that there was an isolated desert in the middle of Pangea with a fauna all its own.

Roaming this desert in what is now northern Niger was a very distinctive creature known as a pareiasaur. Pareiasaurs were large, herbivorous reptiles that were common across Pangea during the Middle and Late Permian, about 266-252 million years ago. "Imagine a cow-sized, plant-eating reptile with a knobby skull and bony armor down its back," said lead author Linda Tsuji. The newly discovered fossils belong to the aptly-named genus Bunostegos, which means "knobby [skull] roof."

Most pareiasaurs had bony knobs on their skulls, but Bunostegos sported the largest, most bulbous ones ever discovered. In life, these were probably skin-covered horns like those on the heads of modern giraffes. Although at first blush these features seem to suggest that Bunostegos was an evolutionarily advanced pareiasaur, it also had many primitive characteristics. Tsuji's analysis showed that Bunostegos was actually more closely related to older and more primitive pareiasaurs, leading to two conclusions: first, that its knobby noggin was the result of convergent evolution, and second, that its genealogical lineage had been isolated for millions of years.

So how do you isolate a population of cow-sized reptiles? Though there were no fences in the Permian, climatic conditions conspired to corral Bunostegos – along with several other reptiles, amphibians, and plants – and keep them constrained to the central area of the supercontinent. "Our work supports the theory that central Pangea was climatically isolated, allowing a unique relict fauna to persist into the Late Permian," said Christian Sidor, another author of the paper. This is surprising because areas outside this central region show fossil evidence of regular faunal interchange.

Geological data also show that central Pangea was hyperarid (extremely dry), effectively discouraging some animals from passing through, while keeping those within from venturing out. The long period of isolation under these parched conditions gave Bunostegos lineage time to evolve its unique anatomical features.

Paleontologist Gabe Bever, who was not involved with the study, said "Research in these lesser-known basins is critically important for meaningful interpretation of the Permian fossil record. Our understanding of the Permian and the mass extinction that ended it depends on discovery of more fossils like the beautifully bizarre Bunostegos."

Paper link later.

Thursday, January 24, 2013

Something Big Was Eating Tetrapods and Fish in the Wujiapingian Permian of Russian

Upper Permian vertebrate coprolites from Vyazniki and Gorokhovets, Vyatkian Regional Stage, Russian Platform

Authors:

1. Krzysztof Owock (a)
2. Grzegorz Niedźwiedzki (b, c, *)
3. Andrey G. Sennikov (d)
4. Valeriy K. Golubev (d)
5. Katarzyna Janiszewska (a)
6. Tomasz Sulej (a)

Affiliations:

a. Institute of Paleobiology, Polish Academy of Sciences, Twarda 51/55, 00-818, Warsaw, Poland

b. Department of Organismal Biology, Uppsala University, Norbyvägen 18A, 752 36
Uppsala, Sweden

c. Department of Paleobiology and Evolution, Faculty of Biology, University of Warsaw, Stefana Banacha 2, 02-097 Warsaw, Poland

d. Borissiak Paleontological Institute, Russian Academy of Sciences, Profsoyuznaya 123, Moscow, 117997 Russia,

*. Corresponding author. Email: grzegorz.niedzwiedzki@ebc.uu.se

Abstract:

Numerous coprolites have been found in the Vyazniki and Gorokhovets localities of European Russia. Five identified coprolite-bearing horizons occur in the upper Permian deposits of the Vyatkian Regional Stage. Coprolites were collected from mudstone with a coprolite breccia-like layer and also from intraformational conglomerates that were deposited in a floodplain and overbank environment. Two coprolite morphotypes (A and B) are recognized from size and shape analysis of 32 specimens. Morphotype A has long, nonsegmented feces. Smaller, cylindrical or tubular-shaped coprolites of morphotype B are commonly segmented. SEM images of the coprolite matrix show spheres and thinwalled vesicles with diameters 0.5–4 μm. Electron Micro Probe (EMP) analyses of polished thin sections show microcrystalline carbonate-fluoride-bearing calcium phosphate with small amounts of calcium replaced in the crystal lattice. Optical microscopy and EMP investigations show that iron and manganese oxides are responsible for elevated iron and manganese concentrations in the bulk mass of coprolites. Other metals (V, Ni) can be associated with oxides forming spheroids with diameters 3–10 μm. REEs (rare earth elements, U, and other trace element concentrations suggest significant eolian sediment input to the burial environment of the coprolites. The scats contain fish scales and bones of tetrapods (amphibians or reptiles). In one large-sized coprolite, a small fragment of therapsid bone was also found. Both morphotypes are matched to carnivorous taxa within the Archosaurus rossicus zone of the Eastern Europe. The size and shape of the best-preserved specimens suggest that they were possibly produced by a large therapsid, anthracosaur, or early archosauromorph predator.

Wednesday, July 29, 2009

Oldest Known Aboreal Herbivore Found...IN THE PERMIAN!

(Reconstruction of the basal anomodont Suminia getmanovi. (a) Flesh and (b) skeletal reconstruction.)
The Late Permian herbivore Suminia and the early evolution of arboreality in terrestrial vertebrate ecosystems


Jorg Frobisch(1)*
Robert R. Reisz(2)

1 Department of Geology, The Field Museum, Chicago, IL 60605, USA
2 Department of Biology, University of Toronto at Mississauga, Mississauga, ON L5L 1C6, Canada

Vertebrates have repeatedly filled and partitioned the terrestrial ecosystem, and have been able to occupy new, previously unexplored habitats throughout their history on land. The arboreal ecospace is particularly important in vertebrate evolution because it provides new food resources and protection from large ground-dwelling predators. We investigated the skeletal anatomy of the Late Permian (approx. 260 Ma) herbivorous synapsid Suminia getmanovi and performed a morphometric analysis of the phalangeal proportions of a great variety of extant and extinct terrestrial and arboreal tetrapods to discern locomotor function and habitat preference in fossil taxa, with special reference to Suminia. The postcranial anatomy of Suminia provides the earliest skeletal evidence for prehensile abilities and arboreality in vertebrates, as indicated by its elongate limbs, intrinsic phalangeal proportions, a divergent first digit and potentially prehensile tail. The morphometric analysis further suggests a differentiation between grasping and clinging morphotypes among arboreal vertebrates, the former displaying elongated proximal phalanges and the latter showing an elongation of the penultimate phalanges. The fossil assemblage that includes Suminia demonstrates that arboreality and resource partitioning occurred shortly after the initial establishment of the modern type of terrestrial vertebrate ecosystems, with a large number of primary consumers and few top predators.


Keywords: Synapsida; Anomodontia; arboreality; terrestrial ecosystem; evolution


WOW!

A fscking Permian squirrel! Or monkey! Well, not exactly, but, fscking wow with a blink tag!

Paper link above...and it's freely available. GO READ!

UPDATE: Possible prehensile tail AND *THUMBS*.