The Experts below are selected from a list of 174 Experts worldwide ranked by ideXlab platform
Ronny Rosler - One of the best experts on this subject based on the ideXlab platform.
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permian scorpions from the petrified forest of chemnitz germany
BMC Evolutionary Biology, 2016Co-Authors: Jason A Dunlop, David A. Legg, Paul A. Selden, Joerg W. Schneider, Victor Fet, Ronny RoslerAbstract:Paleozoic scorpions (Arachnida: Scorpiones) have been widely documented from the Carboniferous Period; which hosts a remarkable assemblage of more than sixty species including both putative stem- and crown-group fossils. By contrast the succeeding Permian Period is almost completely devoid of records, which are currently restricted to a trace fossil from the early Permian of New Mexico, USA and some limb fragments from the late Permian of the Vologda Region, Russia. ?Opsieobuthus tungeri sp. nov. from the Petrified Forest of Chemnitz, Germany represents the first complete body fossils of scorpions from the Permian. Explosive volcanism preserved these remarkable specimens in situ as part of the palaeosol horizon and bedrock of the Petrified Forest, immediately beneath the Zeisigwald tuff horizon. This dates to the early Permian (Sakmarian) or ca. 291 Ma. Intriguingly, the specimens were obtained from a palaeosol horizon with a compacted network of different-sized woody roots and thus have been preserved in situ in their likely life position, even within their original burrows. Differences in the structure of the comb-like pectines in the two fossils offer evidence for sexual dimorphism, and permit further inferences about the ecology and perhaps even the reproductive biology of these animals. As putative members of a Coal Measures genus, these fossils suggest that at least some Carboniferous scorpion lineages extended their range further into the Permian. This contributes towards a picture of scorpion evolution in which both basal and derived (orthostern) forms coexisted for quite some time; probably from the end of the Carboniferous through to at least the mid Triassic.
Paul A. Selden - One of the best experts on this subject based on the ideXlab platform.
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permian scorpions from the petrified forest of chemnitz germany
BMC Evolutionary Biology, 2016Co-Authors: Jason A Dunlop, David A. Legg, Paul A. Selden, Joerg W. Schneider, Victor Fet, Ronny RoslerAbstract:Paleozoic scorpions (Arachnida: Scorpiones) have been widely documented from the Carboniferous Period; which hosts a remarkable assemblage of more than sixty species including both putative stem- and crown-group fossils. By contrast the succeeding Permian Period is almost completely devoid of records, which are currently restricted to a trace fossil from the early Permian of New Mexico, USA and some limb fragments from the late Permian of the Vologda Region, Russia. ?Opsieobuthus tungeri sp. nov. from the Petrified Forest of Chemnitz, Germany represents the first complete body fossils of scorpions from the Permian. Explosive volcanism preserved these remarkable specimens in situ as part of the palaeosol horizon and bedrock of the Petrified Forest, immediately beneath the Zeisigwald tuff horizon. This dates to the early Permian (Sakmarian) or ca. 291 Ma. Intriguingly, the specimens were obtained from a palaeosol horizon with a compacted network of different-sized woody roots and thus have been preserved in situ in their likely life position, even within their original burrows. Differences in the structure of the comb-like pectines in the two fossils offer evidence for sexual dimorphism, and permit further inferences about the ecology and perhaps even the reproductive biology of these animals. As putative members of a Coal Measures genus, these fossils suggest that at least some Carboniferous scorpion lineages extended their range further into the Permian. This contributes towards a picture of scorpion evolution in which both basal and derived (orthostern) forms coexisted for quite some time; probably from the end of the Carboniferous through to at least the mid Triassic.
Joerg W. Schneider - One of the best experts on this subject based on the ideXlab platform.
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permian scorpions from the petrified forest of chemnitz germany
BMC Evolutionary Biology, 2016Co-Authors: Jason A Dunlop, David A. Legg, Paul A. Selden, Joerg W. Schneider, Victor Fet, Ronny RoslerAbstract:Paleozoic scorpions (Arachnida: Scorpiones) have been widely documented from the Carboniferous Period; which hosts a remarkable assemblage of more than sixty species including both putative stem- and crown-group fossils. By contrast the succeeding Permian Period is almost completely devoid of records, which are currently restricted to a trace fossil from the early Permian of New Mexico, USA and some limb fragments from the late Permian of the Vologda Region, Russia. ?Opsieobuthus tungeri sp. nov. from the Petrified Forest of Chemnitz, Germany represents the first complete body fossils of scorpions from the Permian. Explosive volcanism preserved these remarkable specimens in situ as part of the palaeosol horizon and bedrock of the Petrified Forest, immediately beneath the Zeisigwald tuff horizon. This dates to the early Permian (Sakmarian) or ca. 291 Ma. Intriguingly, the specimens were obtained from a palaeosol horizon with a compacted network of different-sized woody roots and thus have been preserved in situ in their likely life position, even within their original burrows. Differences in the structure of the comb-like pectines in the two fossils offer evidence for sexual dimorphism, and permit further inferences about the ecology and perhaps even the reproductive biology of these animals. As putative members of a Coal Measures genus, these fossils suggest that at least some Carboniferous scorpion lineages extended their range further into the Permian. This contributes towards a picture of scorpion evolution in which both basal and derived (orthostern) forms coexisted for quite some time; probably from the end of the Carboniferous through to at least the mid Triassic.
Jason A Dunlop - One of the best experts on this subject based on the ideXlab platform.
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permian scorpions from the petrified forest of chemnitz germany
BMC Evolutionary Biology, 2016Co-Authors: Jason A Dunlop, David A. Legg, Paul A. Selden, Joerg W. Schneider, Victor Fet, Ronny RoslerAbstract:Paleozoic scorpions (Arachnida: Scorpiones) have been widely documented from the Carboniferous Period; which hosts a remarkable assemblage of more than sixty species including both putative stem- and crown-group fossils. By contrast the succeeding Permian Period is almost completely devoid of records, which are currently restricted to a trace fossil from the early Permian of New Mexico, USA and some limb fragments from the late Permian of the Vologda Region, Russia. ?Opsieobuthus tungeri sp. nov. from the Petrified Forest of Chemnitz, Germany represents the first complete body fossils of scorpions from the Permian. Explosive volcanism preserved these remarkable specimens in situ as part of the palaeosol horizon and bedrock of the Petrified Forest, immediately beneath the Zeisigwald tuff horizon. This dates to the early Permian (Sakmarian) or ca. 291 Ma. Intriguingly, the specimens were obtained from a palaeosol horizon with a compacted network of different-sized woody roots and thus have been preserved in situ in their likely life position, even within their original burrows. Differences in the structure of the comb-like pectines in the two fossils offer evidence for sexual dimorphism, and permit further inferences about the ecology and perhaps even the reproductive biology of these animals. As putative members of a Coal Measures genus, these fossils suggest that at least some Carboniferous scorpion lineages extended their range further into the Permian. This contributes towards a picture of scorpion evolution in which both basal and derived (orthostern) forms coexisted for quite some time; probably from the end of the Carboniferous through to at least the mid Triassic.
Patrick Lafaite - One of the best experts on this subject based on the ideXlab platform.
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a complete insect from the late devonian Period
Nature, 2012Co-Authors: Romain Garrouste, Pierre Gueriau, Gaël Clément, Patricial Nel, Michael S Engel, Philippe Grandcolas, Cyrille A Dhaese, Linda Lagebro, Julien Denayer, Patrick LafaiteAbstract:The fossil of a complete insect from the Late Devonian Period (approximately 365 million years ago) is presented; it was terrestrial, but its features suggest that modern winged insects had already started to diversify at that early date. The early evolutionary history of the insects is obscure. Fragmentary remains of insect-like arthropods are known from the Silurian to the mid-Devonian Periods, 425 million to 385 million years ago, whereas modern insects are known from the Carboniferous Period, around 345 million years ago. In between lies a gap, poorly sampled by fossil specimens, during which much evolution is thought to have occurred. Here, Andre Nel and colleagues present the fossil of a complete insect that sits in that gap, about 365 million years ago in the Late Devonian. The fossil insect was terrestrial, but its features suggest that modern winged insects had already started to diversify at that early date. After terrestrialization, the diversification of arthropods and vertebrates is thought to have occurred in two distinct phases1, the first between the Silurian and the Frasnian stages (Late Devonian Period) (425–385 million years (Myr) ago), and the second characterized by the emergence of numerous new major taxa, during the Late Carboniferous Period (after 345 Myr ago). These two diversification Periods bracket the depauperate vertebrate Romer’s gap (360–345 Myr ago) and arthropod gap (385–325 Myr ago)1, which could be due to preservational artefact2,3. Although a recent molecular dating has given an age of 390 Myr for the Holometabola4, the record of hexapods during the Early–Middle Devonian (411.5–391 Myr ago, Pragian to Givetian stages) is exceptionally sparse and based on fragmentary remains, which hinders the timing of this diversification. Indeed, although Devonian Archaeognatha are problematic5,6, the Pragian of Scotland has given some Collembola and the incomplete insect Rhyniognatha, with its diagnostic dicondylic, metapterygotan mandibles5,7. The oldest, definitively winged insects are from the Serpukhovian stage (latest Early Carboniferous Period)8. Here we report the first complete Late Devonian insect, which was probably a terrestrial species. Its ‘orthopteroid’ mandibles are of an omnivorous type, clearly not modified for a solely carnivorous diet. This discovery narrows the 45-Myr gap in the fossil record of Hexapoda, and demonstrates further a first Devonian phase of diversification for the Hexapoda, as in vertebrates, and suggests that the Pterygota diversified before and during Romer’s gap.