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Derek J Siveter - One of the best experts on this subject based on the ideXlab platform.
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the herefordshire Lagerstatte fleshing out silurian marine life
Journal of the Geological Society, 2020Co-Authors: Derek J Siveter, Derek E G Briggs, Mark D SuttonAbstract:The Herefordshire Lagerstatte (c. 430 Myr BP) from the UK is a rare example of soft-tissue preservation in the Silurian. It yields a wide range of Silurian invertebrates in unparalleled three-dimensional detail, dominated by arthropods and sponges. The fossils are exceptionally preserved as calcitic void infills in early diagenetic carbonate concretions within a volcaniclastic (bentonite) horizon. The Lagerstatte occurs in an outer shelf/upper slope setting in the Welsh Basin, which was located on Avalonia in the southern subtropics. The specimens are investigated by serial grinding, digital photography and rendering in the round as a ‘virtual fossil’ by computer. The fossils contribute much to our understanding of the palaeobiology and early history of the groups represented. They are important in demonstrating unusual character combinations that illuminate relationships; in calibrating molecular clocks; in variously linking with taxa in both earlier and later Palaeozoic Lagerstatten; and in providing evidence of the early evolution of crown-group representatives of several groups.
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a three dimensionally preserved lobopodian from the herefordshire silurian Lagerstatte uk
Royal Society Open Science, 2018Co-Authors: Derek J Siveter, Derek E G Briggs, Mark D Sutton, David J Siveter, David A LeggAbstract:The Herefordshire (Silurian) Lagerstatte (approx. 430 Myr BP) has yielded, among many exceptionally preserved invertebrates, a wide range of new genera belonging to crown-group Panarthropoda. Here,...
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a new crustacean from the herefordshire silurian Lagerstatte uk and its significance in malacostracan evolution
Proceedings of The Royal Society B: Biological Sciences, 2017Co-Authors: David J Siveter, Derek J Siveter, Derek E G Briggs, Mark D Sutton, David A LeggAbstract:Cascolus ravitis gen. et sp. nov. is a three-dimensionally preserved fossil crustacean with soft parts from the Herefordshire (Silurian) Lagerstatte, UK. It is characterized by a head with a head s...
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The Radiolaria of the Herefordshire Konservat-Lagerstätte (Silurian), England
Journal of Micropalaeontology, 2007Co-Authors: David J Siveter, Derek J Siveter, Jonathan C. Aitchison, Mark D SuttonAbstract:Concretions of the Wenlock Series Herefordshire Konservat-Lagerstatte of the Welsh Borderland have yielded one of the few recorded Silurian radiolarian faunas world-wide and the only one known from the Silurian of Britain. The low diversity radiolarian fauna consists of new forms of Inaniguttidae (Inanihella sagena sp. nov. and Inanihella sp.), Haplentactiniidae (Haplentactinia armista sp. nov.) and a previously reported form of Secuicollactidae (Secuicollacta hexatinia (Won et al., 2002)). The fauna has affinities with Silurian radiolarian assemblages of the Urals, the Canadian Arctic and Alaska. Stratigraphically the Herefordshire fauna appears transitional between established Silurian radiolarian biozones.
Thijs R A Vandenbroucke - One of the best experts on this subject based on the ideXlab platform.
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palynomorphs of the fezouata shale lower ordovician morocco age and environmental constraints of the fezouata biota
Palaeogeography Palaeoclimatology Palaeoecology, 2016Co-Authors: Hendrik Nowak, Bernard Pittet, Thomas Servais, Thijs R A Vandenbroucke, Robert R Gaines, Mustapha Akodad, Romain VaucherAbstract:Abstract The present study documents new palynological investigations of the Fezouata Shale from the Anti-Atlas (Morocco). Palynomorphs were extracted from samples collected from both outcrops and drill cuttings. Outcrop samples were taken near Zagora, and include some that were collected during excavation of stratigraphic horizons where exceptionally well-preserved fossils of the Fezouata Lagerstatte occur. Subsurface samples were taken from the AZ-1 (Adrar Zouggar Mountain) borehole, which was extracted some 300 km to the southwest of Zagora. The palynological samples yielded acritarchs, chitinozoans, scolecodonts, conodonts and fragments of graptolites. The abundance and quality of preservation of palynomorphs varies greatly, but rich and diverse assemblages were recovered from several samples. The diversity and composition of the assemblages points to an open shelf environment. Generally mixed preservation states suggest resedimentation or differential transport histories. The acritarchs can be assigned to the diagnostic messaoudensis-trifidum acritarch assemblage, which is typical of the Tremadocian/Floian boundary interval of the Gondwanan margin in high southern palaeolatitudes. The acritarch taxa present in some of the lower parts of the Fezouata Shale including levels of exceptional preservation can be attributed to sub-assemblages 1–2 of the messaoudensis-trifidum assemblage and thus point to a late Tremadocian age of the Fezouata Lagerstatte, confirming biostratigraphic data provided by graptolites of the Araneograptus murrayi graptolite biozone. Chitinozoans from the Fezouata Shale are from the E. symmetrica and E. brevis biozones and include various species that are well-known from several localities on the Gondwanan margin and from other palaeocontinents (Baltica, Laurentia, and South China), demarcating broad links between those regions. The coincidence between index fossils of these three groups, hitherto not all found in the same level, suggests that the age assignments of chitinozoan biozones may be in need of revision.
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the lower ordovician fezouata konservat Lagerstatte from morocco age environment and evolutionary perspectives
Gondwana Research, 2016Co-Authors: Emmanuel L O Martin, Bernard Pittet, J C Gutierrezmarco, Jean Vannier, Khadija El Hariri, Rudy Leroseyaubril, Moussa Masrour, Hendrik Nowak, Thomas Servais, Thijs R A VandenbrouckeAbstract:Abstract The Lower Ordovician Fezouata Konservat-Lagerstatte from southern Morocco has been one of the major palaeontological discoveries of the last decade. It provides a unique insight into one of the most critical periods in the evolution of marine life: the Cambrian–Ordovician transition. However, its potential for deciphering key trends in animal diversification was hitherto largely limited by major uncertainties concerning its stratigraphic position, age and environmental setting. Based on extensive fieldwork, fossil evidence, and facies recognition, our study provides clarification on these three crucial issues. Exceptional preservation is limited to two intervals within the Fezouata Shale. Graptolites indicate a late Tremadocian age for the Fezouata Konservat-Lagerstatte as a whole, which is supported by biostratigraphical evidence provided by acritarchs. Sedimentological features and reconstructed patterns of relative sea-level changes indicate relatively shallow-water environmental conditions, under distal storm influence, in an offshore to lower shoreface siliciclastic ramp setting. The Fezouata Biota represents a unique and exceptional window into the palaeobiodiversity in open-marine conditions, thus contrasting with the other Ordovician Konservat-Lagerstatten presently known. In our analyses of this new set of data, we pave the way for accurate temporal, faunal and environmental comparisons with other Lower Palaeozoic Konservat-Lagerstatten, and unlock the full potential of the Fezouata Biota to better understand the processes and scenarios of early animal radiations.
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chitinozoans and the age of the soom shale an ordovician black shale Lagerstatte south africa
Journal of Micropalaeontology, 2009Co-Authors: Sarah E. Gabbott, Thijs R A Vandenbroucke, Richard J. Aldridge, Florentin Paris, Johannes N. TheronAbstract:Isolated chitinozoans from the Soom Shale Member of the Cedarberg Formation, SW South Africa are described and provide a date of the latest Hirnantian–earliest Rhuddanian. The recovered chitinozoans are typical of the latest Ordovician Spinachitina oulebsiri Biozone, although an earliest Silurian age is possible. They indicate a very short time span (less than 1 Ma) across the Ordovician–Silurian boundary. This is currently the highest biostratigraphical resolution attainable for the Soom Shale Lagerstatte. Correlation of the Soom Shale chitinozoans with identical assemblages in post-glacial, transgressive deposits of Northern Africa is possible; both faunas occur in shales that overlie glacial diamictites of the Hirnantian glaciation. A new species, Spinachitina verniersi n. sp. is described.
Sarah E. Gabbott - One of the best experts on this subject based on the ideXlab platform.
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the mazon creek Lagerstatte a diverse late paleozoic ecosystem entombed within siderite concretions
Journal of the Geological Society, 2019Co-Authors: Mark A Purnell, Thomas Clements, Sarah E. GabbottAbstract:One of the best records of late Paleozoic ecosystems, the Mazon Creek Lagerstatte is world famous for its striking flora and fauna preserved within siderite concretions. Distinct from other late Carboniferous concretionary Lagerstatten because of the remarkable fidelity of soft tissues and pigments that are frequently preserved, the Mazon Creek has seen a revival in investigations during the last 10 years using modern palaeontological techniques. However, many of these modern investigations build upon a literature that incorrectly interprets the palaeoenvironment of the Mazon Creek and the separate biotas: there is a lack of evidence to support a distinct freshwater fauna. Here, we present a detailed overview of the Mazon Creek Lagerstatte, including the palaeoenvironmental conditions, organisms present and the complex taphonomic processes involved in fossil formation. Investigation into the formation of siderite concretions and the complex taphonomic processes controlling soft-bodied preservation are still continuing but are reviewed in detail.
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The late Ordovician Soom Shale Lagerstätte: an extraordinary post-glacial fossil and sedimentary record
Journal of the Geological Society, 2016Co-Authors: Sarah E. Gabbott, Claire Browning, Johannes N. Theron, Rowan J. WhittleAbstract:Fossils of the Late Ordovician Soom Shale Lagerstatte are characterized by exceptional preservation of their soft tissues in clay minerals. The low-diversity community lived in an unusual cold-water setting, dominated by anoxic bottom waters, in the immediate aftermath of the Hirnantian glaciation. Giant conodonts represented by complete tooth sets, and one with trunk musculature and liver preserved, unarmoured jawless fish, lobopods and enigmatic taxa are some of the more important fossils. Furthermore, this Lagerstatte also preserves biomineralized Ordovician taxa such as brachiopods, orthoconic nautiloids and trilobites. It is important in capturing the only known examples of many taxa, extending temporal ranges of others and providing a unique glimpse of a post-glacial refugium, at a time when other Lagerstatten are unknown.
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Brachiopoda from the Soom Shale Lagerstätte (Upper Ordovician, South Africa)
Journal of Paleontology, 2009Co-Authors: Michael G. Bassett, Sarah E. Gabbott, Richard J. Aldridge, Leonid E. Popov, Johannes N. TheronAbstract:Abstract Within the Soom Shale Lagerstatte of South Africa (Upper Ordovician, Hirnantian), two brachiopod taxa preserve traces of organic tissue. In Trematis, presumed bands of periostracum are preserved on the flanks of the pedicle notch, and clay mineral casts of the pedicle are preserved in many specimens of Kosoidea. Both these genera are organophosphatic-shelled Linguliformea, together with a third genus identified as Plectoglossa. A fourth brachiopod taxon in the fauna belongs within the calcitic-shelled Rhynchonelliformea (Plectothyrella). Kosoidea cedarbergensis is a new species of discinoidean.
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AN ORDOVICIAN LOBOPODIAN FROM THE SOOM SHALE LAGERSTÄTTE, SOUTH AFRICA
Palaeontology, 2009Co-Authors: Rowan J. Whittle, Sarah E. Gabbott, Richard J. Aldridge, Johannes N. TheronAbstract:The first lobopodian known from the Ordovician is described from the Soom Shale Lagerstatte, South Africa. The organism shows features homologous to Palaeozoic marine lobopodians described from the Middle Cambrian Burgess Shale, the Lower Cambrian Chengjiang biota, the Lower Cambrian Sirius Passet Lagerstatte and the Lower Cambrian of the Baltic. The discovery provides a link between marine Cambrian lobopodians and younger forms from the Silurian and Carboniferous. The new fossil preserves an annulated trunk, lobopods with clear annulations, and curved claws. It represents a rare record of a benthic organism from the Soom Shale, and demonstrates intermittent water oxygenation during the deposition of the unit.
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chitinozoans and the age of the soom shale an ordovician black shale Lagerstatte south africa
Journal of Micropalaeontology, 2009Co-Authors: Sarah E. Gabbott, Thijs R A Vandenbroucke, Richard J. Aldridge, Florentin Paris, Johannes N. TheronAbstract:Isolated chitinozoans from the Soom Shale Member of the Cedarberg Formation, SW South Africa are described and provide a date of the latest Hirnantian–earliest Rhuddanian. The recovered chitinozoans are typical of the latest Ordovician Spinachitina oulebsiri Biozone, although an earliest Silurian age is possible. They indicate a very short time span (less than 1 Ma) across the Ordovician–Silurian boundary. This is currently the highest biostratigraphical resolution attainable for the Soom Shale Lagerstatte. Correlation of the Soom Shale chitinozoans with identical assemblages in post-glacial, transgressive deposits of Northern Africa is possible; both faunas occur in shales that overlie glacial diamictites of the Hirnantian glaciation. A new species, Spinachitina verniersi n. sp. is described.
David J Siveter - One of the best experts on this subject based on the ideXlab platform.
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a three dimensionally preserved lobopodian from the herefordshire silurian Lagerstatte uk
Royal Society Open Science, 2018Co-Authors: Derek J Siveter, Derek E G Briggs, Mark D Sutton, David J Siveter, David A LeggAbstract:The Herefordshire (Silurian) Lagerstatte (approx. 430 Myr BP) has yielded, among many exceptionally preserved invertebrates, a wide range of new genera belonging to crown-group Panarthropoda. Here,...
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a new crustacean from the herefordshire silurian Lagerstatte uk and its significance in malacostracan evolution
Proceedings of The Royal Society B: Biological Sciences, 2017Co-Authors: David J Siveter, Derek J Siveter, Derek E G Briggs, Mark D Sutton, David A LeggAbstract:Cascolus ravitis gen. et sp. nov. is a three-dimensionally preserved fossil crustacean with soft parts from the Herefordshire (Silurian) Lagerstatte, UK. It is characterized by a head with a head s...
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isoxys arthropoda with preserved soft anatomy from the sirius passet Lagerstatte lower cambrian of north greenland
Lethaia, 2009Co-Authors: Martin Stein, John S Peel, David J Siveter, M WilliamsAbstract:Arthropods have a rich fossil record spanning the Phanerozoic. Biomineralized forms such as the extinct trilobites are particularly common and are proven index fossils for biostratigraphy. Forms with an unmineralized cuticle are more rare, preserved only in so called konservat Lagerstatten. Cambrian strata of Greenland have yielded rich trilobite faunas with potential for intercontinental correlation of Cambrian strata, but also an exceptionally preserved fauna, the Sirius Passet Lagerstatte. The first part of this thesis is concerned with trilobite biotratigraphy of the provisional Cambrian Series 2 in Greenland. The second part is concerned with exceptionally preserved arthropods from the Sirius Passet Lagerstatte, but also from 'Orsten' deposits from the Cambrian of Sweden. Perissopyge phenax occurs in the Henson Gletscher and Paralleldal formations spanning the Series 2 and 3 boundary interval in North Greenland. It also occurs in the Sekwi Formation of Yukon Territory, demonstrating that the species may hold potential for correlation within Laurentia. An indeterminate species of Perissopyge is shown to occur in the Ella Island Formation of North-East Greenland together with Olenellus cf. hanseni, which is similar to Olenellus cf. truemani described from the Henson Gletscher Formation. If this correlation is further corroborated it would offer a first tie-point for the An t'Sron Formation of North-West Scotland which yields Fritzolenellus lapworthi, herein reported for the first time from the Bastion Formation which underlies the Ella Island Formation. Oelandocaris oelandica from ‘Orsten’ deposits in the Cambrian series 3 and 4 boundary interval in Sweden is an early representative of the Crustacean stem lineage. Kiisortoqia avannaarsuensis is a new arthropod from the Sirius Passet Lagerstatte with robust antennulae strikingly similar to the 'raptorial' limb of the problematic anomalocaridids. The ventral morphology of the 'bivalved' Isoxys volucris is described for the first time and compared with other species assigned to Isoxys from Cambrian Lagerstatten around the world. Finally, Siriocaris trolla, is a new arthropod that similarities with trilobites and certain ‘trilobitomorphs’ but seems to lack important synapomorphies of these taxa, though this may be due to preservational limitations in the material at hand.
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The Radiolaria of the Herefordshire Konservat-Lagerstätte (Silurian), England
Journal of Micropalaeontology, 2007Co-Authors: David J Siveter, Derek J Siveter, Jonathan C. Aitchison, Mark D SuttonAbstract:Concretions of the Wenlock Series Herefordshire Konservat-Lagerstatte of the Welsh Borderland have yielded one of the few recorded Silurian radiolarian faunas world-wide and the only one known from the Silurian of Britain. The low diversity radiolarian fauna consists of new forms of Inaniguttidae (Inanihella sagena sp. nov. and Inanihella sp.), Haplentactiniidae (Haplentactinia armista sp. nov.) and a previously reported form of Secuicollactidae (Secuicollacta hexatinia (Won et al., 2002)). The fauna has affinities with Silurian radiolarian assemblages of the Urals, the Canadian Arctic and Alaska. Stratigraphically the Herefordshire fauna appears transitional between established Silurian radiolarian biozones.
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The earliest myodocopes: ostracodes from the late Ordovician Soom Shale Lagerstätte of South Africa
Lethaia, 2003Co-Authors: Sarah E. Gabbott, David J Siveter, Richard J. Aldridge, Johannes N. TheronAbstract:The late Ordovician Soom Shale Lagerstatte of South Africa has yielded Myodoprimigenia fistuca n. gen. and n. sp., the earliest and only known Ordovician occurrence of myodocopes, one of the major groups of ostracodes. M. fistuca is a likely sister group of the Upper Silurian ‘cypridinid’ myodocopes and allied forms. It had a thin, lightly mineralized and flexible shell with microstructures resulting from in vivo calcification processes. It probably fed on cephalopod carrion, thus extending evidence for a carnivorous scavenging lifestyle in ostracodes back by 200 Ma. The species was probably nektobenthic and thus consistent with the notion that the origin of the late Silurian pelagic myodocopes - and therefore of pelagic ostracodes - is to be charted in a benthic to pelagic ecological shift in the group.
Derek E G Briggs - One of the best experts on this subject based on the ideXlab platform.
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the herefordshire Lagerstatte fleshing out silurian marine life
Journal of the Geological Society, 2020Co-Authors: Derek J Siveter, Derek E G Briggs, Mark D SuttonAbstract:The Herefordshire Lagerstatte (c. 430 Myr BP) from the UK is a rare example of soft-tissue preservation in the Silurian. It yields a wide range of Silurian invertebrates in unparalleled three-dimensional detail, dominated by arthropods and sponges. The fossils are exceptionally preserved as calcitic void infills in early diagenetic carbonate concretions within a volcaniclastic (bentonite) horizon. The Lagerstatte occurs in an outer shelf/upper slope setting in the Welsh Basin, which was located on Avalonia in the southern subtropics. The specimens are investigated by serial grinding, digital photography and rendering in the round as a ‘virtual fossil’ by computer. The fossils contribute much to our understanding of the palaeobiology and early history of the groups represented. They are important in demonstrating unusual character combinations that illuminate relationships; in calibrating molecular clocks; in variously linking with taxa in both earlier and later Palaeozoic Lagerstatten; and in providing evidence of the early evolution of crown-group representatives of several groups.
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a three dimensionally preserved lobopodian from the herefordshire silurian Lagerstatte uk
Royal Society Open Science, 2018Co-Authors: Derek J Siveter, Derek E G Briggs, Mark D Sutton, David J Siveter, David A LeggAbstract:The Herefordshire (Silurian) Lagerstatte (approx. 430 Myr BP) has yielded, among many exceptionally preserved invertebrates, a wide range of new genera belonging to crown-group Panarthropoda. Here,...
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taphonomy and biological affinity of three dimensionally phosphatized bromalites from the middle ordovician winneshiek Lagerstatte northeastern iowa usa
PALAIOS, 2018Co-Authors: Andrew D Hawkins, Derek E G Briggs, Robert Mckay, Brian J Witzke, A D Muscente, Shuhai XiaoAbstract:Abstract The Winneshiek Lagerstatte occurs within an Ordovician meteorite impact structure beneath part of the city of Decorah, Iowa. The Lagerstatte has yielded an atypical marine fauna including phyllocarid crustaceans, eurypterids, conodonts, linguloid brachiopods, and jawless fish. Associated with these taxa are vermiform fossils: elongate, morphologically variable, and often three-dimensionally preserved bromalites of uncertain organisms. The preservational state of these bromalites is significantly different from that of other components of the Winneshiek biota. Here we present a compositional and microstructural analysis of the vermiform fossils in order to elucidate their taphonomy and biological affinities. The majority of studied specimens are preserved three-dimensionally and composed of calcium phosphate, while a minority are preserved as carbonaceous compressions. Winneshiek bromalites exhibit important similarities to examples documented from both older and younger sediments. They provide in...
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a new crustacean from the herefordshire silurian Lagerstatte uk and its significance in malacostracan evolution
Proceedings of The Royal Society B: Biological Sciences, 2017Co-Authors: David J Siveter, Derek J Siveter, Derek E G Briggs, Mark D Sutton, David A LeggAbstract:Cascolus ravitis gen. et sp. nov. is a three-dimensionally preserved fossil crustacean with soft parts from the Herefordshire (Silurian) Lagerstatte, UK. It is characterized by a head with a head s...
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a new Lagerstatte from the late ordovician big hill formation upper peninsula michigan
Journal of the Geological Society, 2017Co-Authors: Derek E G Briggs, James C Lamsdell, Steven T Loduca, Gerald O Gunderson, Ronald C MeyerAbstract:A new exceptionally preserved marginal marine biota is reported from the Late Ordovician Big Hill Formation of Stonington Peninsula in Michigan9s Upper Peninsula. The new Lagerstatte hosts a moderately diverse fauna of medusae, linguloid brachiopods, non-mineralized arthropods and orthocone nautiloids, alongside dasycladalean green algae. The biota is similar to those of Lagerstatten from the Late Ordovician of Canada, revealing an extensive distribution of a distinctive marginal marine palaeocommunity in Laurentia at this time. The Big Hill biota extends the geographical range of exceptionally preserved Late Ordovician faunas in Laurentia and indicates that further examples remain to be discovered.
