The Experts below are selected from a list of 168654 Experts worldwide ranked by ideXlab platform
Thomas Wilke - One of the best experts on this subject based on the ideXlab platform.
-
testing the spatial and Temporal Framework of speciation in an ancient lake species flock the leech genus dina hirudinea erpobdellidae in lake ohrid
Biogeosciences, 2010Co-Authors: Sasho Trajanovski, Christian Albrecht, Kirstin Schreiber, Tanja Stadler, Mandy Benke, Roland Schultheis, Thomas WilkeAbstract:Abstract. Ancient Lake Ohrid on the Balkan Peninsula is considered to be the oldest ancient lake in Europe with a suggested Plio-/Pleistocene age. Its exact geological age, however, remains unknown. Therefore, molecular clock data of Lake Ohrid biota may serve as an independent constraint of available geological data, and may thus help to refine age estimates. Such evolutionary data may also help unravel potential biotic and abiotic factors that promote speciation events. Here, mitochondrial sequencing data of one of the largest groups of endemic taxa in the Ohrid watershed, the leech genus Dina, is used to test whether it represents an ancient lake species flock, to study the role of potential horizontal and vertical barriers in the watershed for evolutionary events, to estimate the onset of diversification in this group based on molecular clock analyses, and to compare this data with data from other endemic species for providing an approximate time frame for the origin of Lake Ohrid. Based on the criteria speciosity, monophyly and endemicity, it can be concluded that Dina spp. from the Ohrid watershed, indeed, represents an ancient lake species flock. Lineage sorting of its species, however, does not seem to be complete and/or hybridization may occur. Analyses of population structures of Dina spp. in the Ohrid watershed indicate a horizontal zonation of haplotypes from spring and lake populations, corroborating the role of lake-side springs, particularly the southern feeder springs, for evolutionary processes in endemic Ohrid taxa. Vertical differentiation of lake taxa, however, appears to be limited, though differences between populations from the littoral and the profundal are apparent. Molecular clock analyses indicate that the most recent common ancestor of extant species of this flock is approximately 1.99 ± 0.83 million years (Ma) old, whereas the split of the Ohrid Dina flock from a potential sister taxon outside the lake is estimated at 8.30 ± 3.60 Ma. Comparisons with other groups of endemic Ohrid species indicated that in all cases, diversification within the watershed started ≤2 Ma ago. Thus, this estimate may provide information on a minimum age for the origin of Lake Ohrid. Maximum ages are less consistent and generally less reliable. But cautiously, a maximum age of 3 Ma is suggested. Interestingly, this time frame of approximately 2–3 Ma ago for the origin of Lake Ohrid, generated based on genetic data, well fits the time frame most often used in the literature by geologists.
-
testing the spatial and Temporal Framework of speciation in an ancient lake species flock
Biogeosciences, 2010Co-Authors: Sasho Trajanovski, Christian Albrecht, Kirstin Schreiber, R Schultheiss, Tanja Stadler, Mandy Benke, Thomas WilkeAbstract:Ancient Lake Ohrid on the Balkan Peninsula is considered to be the oldest ancient lake in Europe with a suggested Plio-Pleistocene age. Its exact geological age, however, remains unknown. Therefore, molecular clock data of Lake Ohrid biota may serve as an independent constraint of available geological data, and may thus also help to refine age estimates. Such evolutionary data may also help unravel potential biotic and abiotic factors that promote speciation events. Here, mitochondrial sequencing data of one of the largest groups of endemic taxa in Lake Ohrid, the leech genus Dina, is used to test whether it represents an ancient lake species flock, to study the role of horizontal and vertical barriers in Lake Ohrid for evolutionary events, to estimate the onset of intralacustrine diversification in this group based on molecular clock analyses, and to compare this data with data from other endemic species for providing an approximate time frame for the origin of Lake Ohrid. Based on the criteria speciosity, monophyly and endemicity, it can be concluded that Lake Ohrid Dina, indeed, represents an ancient lake species flock. Lineage sorting of its species, however, does not seem to be complete. Analyses of population structures of Dina spp. in the Ohrid watershed indicate a horizontal zonation of haplotypes from spring and lake populations, corroborating the role of lake-side springs, particularly the southern feeder springs, for evolutionary processes in endemic Ohrid taxa. Vertical differentiation of lake taxa, however, appears to be limited, though differences between populations from the littoral and the profundal are apparent. Molecular clock analyses indicate that the most recent common ancestor of extant species of this flock is approximately 1.99±0.83 Ma old, whereas the split of the Lake Ohrid Dina flock from a potential sister taxon outside the lake is estimated at 8.30±3.60 Ma. Comparisons with other groups of endemic Ohrid species indicated that in all cases, intralacustrine diversification started ≤2 Ma ago. Thus, this estimate may provide information on a minimum age for the origin of Lake Ohrid. Maximum ages are less consistent and generally less reliable. But cautiously, a maximum age of 3 Ma is suggested. Interestingly, this time frame of approximately 2–3 Ma for the origin of Lake Ohrid, generated based solely on evolutionary data, well fits the time frame most often used in the literature by geologists. Future studies must show whether this concurrence holds true.
Charles H. Wellman - One of the best experts on this subject based on the ideXlab platform.
-
A high-precision U–Pb age constraint on the Rhynie Chert Konservat-Lagerstätte: time scale and other implications
2016Co-Authors: S F Parry, S R Noble, Quentin G Crowley, Charles H. WellmanAbstract:An isotope dilution thermal ionization mass spectrometry U–Pb zircon age of 411.5 ± 1.3 Ma obtained from an andesitic lava occurring within the Lower Devonian Rhynie Outlier (Aberdeenshire, NE Scotland) effectively dates the Rhynie Chert Konservat-Lagerstätte. Biostratigraphical constraints on the Rhynie Chert-bearing succession indicate that this age lies within the interval early (but not earliest) Pragian–(?)earliest Emsian. Accordingly, the Pragian–Emsian boundary must post-date or closely approximate to 411.5 ± 1.3 Ma, while the Lochkovian–Pragian boundary must predate 411.5 ± 1.3 Ma. Integration of this new high-precision age with an improved Temporal Framework for late Caledonian intrusive activity in NE Scotland suggests that the Rhynie hot-spring system (the ‘parental' hydrothermal system to the Rhynie cherts) was unrelated to any ‘Newer Granite' intrusion. Rhynie was instead powered by a basaltic andesite magma whose generation and ascent were directly linked to the transcurrent fault movements responsible for the formation of the Rhynie basin.
-
a high precision u pb age constraint on the rhynie chert konservat lagerstatte time scale and other implications
Journal of the Geological Society, 2011Co-Authors: S F Parry, S R Noble, Quentin G Crowley, Charles H. WellmanAbstract:Abstract: An isotope dilution thermal ionization mass spectrometry U–Pb zircon age of 411.5 ± 1.3 Ma obtained from an andesitic lava occurring within the Lower Devonian Rhynie Outlier (Aberdeenshire, NE Scotland) effectively dates the Rhynie Chert Konservat-Lagerstatte. Biostratigraphical constraints on the Rhynie Chert-bearing succession indicate that this age lies within the interval early (but not earliest) Pragian–(?)earliest Emsian. Accordingly, the Pragian–Emsian boundary must post-date or closely approximate to 411.5 ± 1.3 Ma, while the Lochkovian–Pragian boundary must predate 411.5 ± 1.3 Ma. Integration of this new high-precision age with an improved Temporal Framework for late Caledonian intrusive activity in NE Scotland suggests that the Rhynie hot-spring system (the ‘parental9 hydrothermal system to the Rhynie cherts) was unrelated to any ‘Newer Granite9 intrusion. Rhynie was instead powered by a basaltic andesite magma whose generation and ascent were directly linked to the transcurrent fault movements responsible for the formation of the Rhynie basin. Supplementary material: Details of analytical techniques (ID-TIMS U–Pb geochronology) and photomicrographs of zircon and titanite grains recovered from the Milton of Noth Andesite are available at http://www.geolsoc.org.uk/SUP18463.
-
a high precision u pb age constraint on the rhynie chert konservat lagerstatte time scale and other implications
Journal of the Geological Society, 2011Co-Authors: S F Parry, S R Noble, Quentin G Crowley, Charles H. WellmanAbstract:Abstract: An isotope dilution thermal ionization mass spectrometry U–Pb zircon age of 411.5 ± 1.3 Ma obtained from an andesitic lava occurring within the Lower Devonian Rhynie Outlier (Aberdeenshire, NE Scotland) effectively dates the Rhynie Chert Konservat-Lagerstatte. Biostratigraphical constraints on the Rhynie Chert-bearing succession indicate that this age lies within the interval early (but not earliest) Pragian–(?)earliest Emsian. Accordingly, the Pragian–Emsian boundary must post-date or closely approximate to 411.5 ± 1.3 Ma, while the Lochkovian–Pragian boundary must predate 411.5 ± 1.3 Ma. Integration of this new high-precision age with an improved Temporal Framework for late Caledonian intrusive activity in NE Scotland suggests that the Rhynie hot-spring system (the ‘parental9 hydrothermal system to the Rhynie cherts) was unrelated to any ‘Newer Granite9 intrusion. Rhynie was instead powered by a basaltic andesite magma whose generation and ascent were directly linked to the transcurrent fault movements responsible for the formation of the Rhynie basin. Supplementary material: Details of analytical techniques (ID-TIMS U–Pb geochronology) and photomicrographs of zircon and titanite grains recovered from the Milton of Noth Andesite are available at http://www.geolsoc.org.uk/SUP18463.
Sasho Trajanovski - One of the best experts on this subject based on the ideXlab platform.
-
testing the spatial and Temporal Framework of speciation in an ancient lake species flock the leech genus dina hirudinea erpobdellidae in lake ohrid
Biogeosciences, 2010Co-Authors: Sasho Trajanovski, Christian Albrecht, Kirstin Schreiber, Tanja Stadler, Mandy Benke, Roland Schultheis, Thomas WilkeAbstract:Abstract. Ancient Lake Ohrid on the Balkan Peninsula is considered to be the oldest ancient lake in Europe with a suggested Plio-/Pleistocene age. Its exact geological age, however, remains unknown. Therefore, molecular clock data of Lake Ohrid biota may serve as an independent constraint of available geological data, and may thus help to refine age estimates. Such evolutionary data may also help unravel potential biotic and abiotic factors that promote speciation events. Here, mitochondrial sequencing data of one of the largest groups of endemic taxa in the Ohrid watershed, the leech genus Dina, is used to test whether it represents an ancient lake species flock, to study the role of potential horizontal and vertical barriers in the watershed for evolutionary events, to estimate the onset of diversification in this group based on molecular clock analyses, and to compare this data with data from other endemic species for providing an approximate time frame for the origin of Lake Ohrid. Based on the criteria speciosity, monophyly and endemicity, it can be concluded that Dina spp. from the Ohrid watershed, indeed, represents an ancient lake species flock. Lineage sorting of its species, however, does not seem to be complete and/or hybridization may occur. Analyses of population structures of Dina spp. in the Ohrid watershed indicate a horizontal zonation of haplotypes from spring and lake populations, corroborating the role of lake-side springs, particularly the southern feeder springs, for evolutionary processes in endemic Ohrid taxa. Vertical differentiation of lake taxa, however, appears to be limited, though differences between populations from the littoral and the profundal are apparent. Molecular clock analyses indicate that the most recent common ancestor of extant species of this flock is approximately 1.99 ± 0.83 million years (Ma) old, whereas the split of the Ohrid Dina flock from a potential sister taxon outside the lake is estimated at 8.30 ± 3.60 Ma. Comparisons with other groups of endemic Ohrid species indicated that in all cases, diversification within the watershed started ≤2 Ma ago. Thus, this estimate may provide information on a minimum age for the origin of Lake Ohrid. Maximum ages are less consistent and generally less reliable. But cautiously, a maximum age of 3 Ma is suggested. Interestingly, this time frame of approximately 2–3 Ma ago for the origin of Lake Ohrid, generated based on genetic data, well fits the time frame most often used in the literature by geologists.
-
testing the spatial and Temporal Framework of speciation in an ancient lake species flock
Biogeosciences, 2010Co-Authors: Sasho Trajanovski, Christian Albrecht, Kirstin Schreiber, R Schultheiss, Tanja Stadler, Mandy Benke, Thomas WilkeAbstract:Ancient Lake Ohrid on the Balkan Peninsula is considered to be the oldest ancient lake in Europe with a suggested Plio-Pleistocene age. Its exact geological age, however, remains unknown. Therefore, molecular clock data of Lake Ohrid biota may serve as an independent constraint of available geological data, and may thus also help to refine age estimates. Such evolutionary data may also help unravel potential biotic and abiotic factors that promote speciation events. Here, mitochondrial sequencing data of one of the largest groups of endemic taxa in Lake Ohrid, the leech genus Dina, is used to test whether it represents an ancient lake species flock, to study the role of horizontal and vertical barriers in Lake Ohrid for evolutionary events, to estimate the onset of intralacustrine diversification in this group based on molecular clock analyses, and to compare this data with data from other endemic species for providing an approximate time frame for the origin of Lake Ohrid. Based on the criteria speciosity, monophyly and endemicity, it can be concluded that Lake Ohrid Dina, indeed, represents an ancient lake species flock. Lineage sorting of its species, however, does not seem to be complete. Analyses of population structures of Dina spp. in the Ohrid watershed indicate a horizontal zonation of haplotypes from spring and lake populations, corroborating the role of lake-side springs, particularly the southern feeder springs, for evolutionary processes in endemic Ohrid taxa. Vertical differentiation of lake taxa, however, appears to be limited, though differences between populations from the littoral and the profundal are apparent. Molecular clock analyses indicate that the most recent common ancestor of extant species of this flock is approximately 1.99±0.83 Ma old, whereas the split of the Lake Ohrid Dina flock from a potential sister taxon outside the lake is estimated at 8.30±3.60 Ma. Comparisons with other groups of endemic Ohrid species indicated that in all cases, intralacustrine diversification started ≤2 Ma ago. Thus, this estimate may provide information on a minimum age for the origin of Lake Ohrid. Maximum ages are less consistent and generally less reliable. But cautiously, a maximum age of 3 Ma is suggested. Interestingly, this time frame of approximately 2–3 Ma for the origin of Lake Ohrid, generated based solely on evolutionary data, well fits the time frame most often used in the literature by geologists. Future studies must show whether this concurrence holds true.
Pau Balaguer - One of the best experts on this subject based on the ideXlab platform.
-
exploring rock coast bioerosion rock fragment intestine transit time and erosion rates computation of the gastropod monodonta articulata lamarck 1822
Journal of Coastal Research, 2013Co-Authors: Maria Vidal, Joan J. Fornós, Miquel Palmer, Lluis Gomezpujol, Guillem X Pons, Pau BalaguerAbstract:ABSTRACT Vidal, M., Fornos, J.J., Gomez-Pujol, L., Palmer, M., Pons, G.X., Balaguer, P., 2013. Exploring rock coast bioerosion: rock fragment intestine transit time and erosion rates computation of the gastropod Monodonta articulata (Lamarck, 1822) Coastal rock bioerosion research is well established. Otherwise there is the need to improve the way in which bioerosion rates are calculated. Since the findings of McLean (1967), it has been assumed that the dry weight of pellets collected after 24 hours provides an estimate of the amount of organism daily erosion. This is an assumption that relies largely on initial experimental procedures lacking any empirical ascertainment. This paper assess what is the transit time of the rock fragments through the intestine of the gastropod Monodonta articulata, and the implications of applicability of this Temporal Framework to the computation of a more precise estimation of the bioerosion throughout laboratory experiments. Our results suggest that for the gastropod Mono...
-
exploring rock coast bioerosion rock fragment intestine transit time and erosion rates computation of the gastropod monodonta articulata lamarck 1822
Journal of Coastal Research, 2013Co-Authors: Maria Vidal, Joan J. Fornós, Miquel Palmer, Lluis Gomezpujol, Guillem X Pons, Pau BalaguerAbstract:ABSTRACT Vidal, M., Fornos, J.J., Gomez-Pujol, L., Palmer, M., Pons, G.X., Balaguer, P., 2013. Exploring rock coast bioerosion: rock fragment intestine transit time and erosion rates computation of the gastropod Monodonta articulata (Lamarck, 1822) Coastal rock bioerosion research is well established. Otherwise there is the need to improve the way in which bioerosion rates are calculated. Since the findings of McLean (1967), it has been assumed that the dry weight of pellets collected after 24 hours provides an estimate of the amount of organism daily erosion. This is an assumption that relies largely on initial experimental procedures lacking any empirical ascertainment. This paper assess what is the transit time of the rock fragments through the intestine of the gastropod Monodonta articulata, and the implications of applicability of this Temporal Framework to the computation of a more precise estimation of the bioerosion throughout laboratory experiments. Our results suggest that for the gastropod Mono...
S F Parry - One of the best experts on this subject based on the ideXlab platform.
-
A high-precision U–Pb age constraint on the Rhynie Chert Konservat-Lagerstätte: time scale and other implications
2016Co-Authors: S F Parry, S R Noble, Quentin G Crowley, Charles H. WellmanAbstract:An isotope dilution thermal ionization mass spectrometry U–Pb zircon age of 411.5 ± 1.3 Ma obtained from an andesitic lava occurring within the Lower Devonian Rhynie Outlier (Aberdeenshire, NE Scotland) effectively dates the Rhynie Chert Konservat-Lagerstätte. Biostratigraphical constraints on the Rhynie Chert-bearing succession indicate that this age lies within the interval early (but not earliest) Pragian–(?)earliest Emsian. Accordingly, the Pragian–Emsian boundary must post-date or closely approximate to 411.5 ± 1.3 Ma, while the Lochkovian–Pragian boundary must predate 411.5 ± 1.3 Ma. Integration of this new high-precision age with an improved Temporal Framework for late Caledonian intrusive activity in NE Scotland suggests that the Rhynie hot-spring system (the ‘parental' hydrothermal system to the Rhynie cherts) was unrelated to any ‘Newer Granite' intrusion. Rhynie was instead powered by a basaltic andesite magma whose generation and ascent were directly linked to the transcurrent fault movements responsible for the formation of the Rhynie basin.
-
a high precision u pb age constraint on the rhynie chert konservat lagerstatte time scale and other implications
Journal of the Geological Society, 2011Co-Authors: S F Parry, S R Noble, Quentin G Crowley, Charles H. WellmanAbstract:Abstract: An isotope dilution thermal ionization mass spectrometry U–Pb zircon age of 411.5 ± 1.3 Ma obtained from an andesitic lava occurring within the Lower Devonian Rhynie Outlier (Aberdeenshire, NE Scotland) effectively dates the Rhynie Chert Konservat-Lagerstatte. Biostratigraphical constraints on the Rhynie Chert-bearing succession indicate that this age lies within the interval early (but not earliest) Pragian–(?)earliest Emsian. Accordingly, the Pragian–Emsian boundary must post-date or closely approximate to 411.5 ± 1.3 Ma, while the Lochkovian–Pragian boundary must predate 411.5 ± 1.3 Ma. Integration of this new high-precision age with an improved Temporal Framework for late Caledonian intrusive activity in NE Scotland suggests that the Rhynie hot-spring system (the ‘parental9 hydrothermal system to the Rhynie cherts) was unrelated to any ‘Newer Granite9 intrusion. Rhynie was instead powered by a basaltic andesite magma whose generation and ascent were directly linked to the transcurrent fault movements responsible for the formation of the Rhynie basin. Supplementary material: Details of analytical techniques (ID-TIMS U–Pb geochronology) and photomicrographs of zircon and titanite grains recovered from the Milton of Noth Andesite are available at http://www.geolsoc.org.uk/SUP18463.
-
a high precision u pb age constraint on the rhynie chert konservat lagerstatte time scale and other implications
Journal of the Geological Society, 2011Co-Authors: S F Parry, S R Noble, Quentin G Crowley, Charles H. WellmanAbstract:Abstract: An isotope dilution thermal ionization mass spectrometry U–Pb zircon age of 411.5 ± 1.3 Ma obtained from an andesitic lava occurring within the Lower Devonian Rhynie Outlier (Aberdeenshire, NE Scotland) effectively dates the Rhynie Chert Konservat-Lagerstatte. Biostratigraphical constraints on the Rhynie Chert-bearing succession indicate that this age lies within the interval early (but not earliest) Pragian–(?)earliest Emsian. Accordingly, the Pragian–Emsian boundary must post-date or closely approximate to 411.5 ± 1.3 Ma, while the Lochkovian–Pragian boundary must predate 411.5 ± 1.3 Ma. Integration of this new high-precision age with an improved Temporal Framework for late Caledonian intrusive activity in NE Scotland suggests that the Rhynie hot-spring system (the ‘parental9 hydrothermal system to the Rhynie cherts) was unrelated to any ‘Newer Granite9 intrusion. Rhynie was instead powered by a basaltic andesite magma whose generation and ascent were directly linked to the transcurrent fault movements responsible for the formation of the Rhynie basin. Supplementary material: Details of analytical techniques (ID-TIMS U–Pb geochronology) and photomicrographs of zircon and titanite grains recovered from the Milton of Noth Andesite are available at http://www.geolsoc.org.uk/SUP18463.
