Parastrophinella (Brachiopoda): Its paleogeographic significance at the Ordovician/Silurian boundary
The type species of Parastrophinella, P. reversa, a pentamerid brachiopod from the uppermost Ordovician (Hirnantian) Ellis Bay Formation of Anticosti Island, Quebec, shows that the genus is characterized by three features: 1) a ventral median septum apically buried in a thickened valve floor, but an...
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Online Access: | http://dx.doi.org/10.1017/s0022336000039391 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022336000039391 |
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crcambridgeupr:10.1017/s0022336000039391 2024-09-15T17:57:05+00:00 Parastrophinella (Brachiopoda): Its paleogeographic significance at the Ordovician/Silurian boundary Jin, Jisuo Copper, Paul 1997 http://dx.doi.org/10.1017/s0022336000039391 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022336000039391 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Journal of Paleontology volume 71, issue 3, page 369-380 ISSN 0022-3360 1937-2337 journal-article 1997 crcambridgeupr https://doi.org/10.1017/s0022336000039391 2024-07-10T04:04:08Z The type species of Parastrophinella, P. reversa, a pentamerid brachiopod from the uppermost Ordovician (Hirnantian) Ellis Bay Formation of Anticosti Island, Quebec, shows that the genus is characterized by three features: 1) a ventral median septum apically buried in a thickened valve floor, but anteriorly rising above valve floor; 2) prominent alate plates, which are homologous to brachial processes; and, 3) a pseudocruralium consisting of a dorsal median septum, which is largely buried in the valve floor posteriorly, and outer plates that are connected to the median septum via prismatic substance (with poorly developed lamellar layer at the junctions) at, or slightly above, the valve floor. These constitute criteria by which many species previously assigned to Parastrophinella are excluded from the genus. Late Ordovician species that fit the redefinition of Parastrophinella are now confined to eastern North America. The genus crosses the Ordovician/Silurian boundary without major morphologic change, and Early Silurian species of Parastrophinella occur in both eastern North America and Great Britain. In the Late Ordovician, the pentamerid fauna of North America (Laurentia) contrasted sharply with that of Baltica and Kazakhstan, where the Holorhynchus fauna was dominant. Typical elements of the Holorhynchus fauna, such as the large-shelled Holorhynchus and Proconchidium, are known only in the northern parts of Laurentia (Baffin Island, Greenland, and Kolyma), and are absent in the Hudson Bay and Williston basins and southwards. Article in Journal/Newspaper Baffin Island Baffin Greenland Hudson Bay Cambridge University Press Journal of Paleontology 71 3 369 380 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
The type species of Parastrophinella, P. reversa, a pentamerid brachiopod from the uppermost Ordovician (Hirnantian) Ellis Bay Formation of Anticosti Island, Quebec, shows that the genus is characterized by three features: 1) a ventral median septum apically buried in a thickened valve floor, but anteriorly rising above valve floor; 2) prominent alate plates, which are homologous to brachial processes; and, 3) a pseudocruralium consisting of a dorsal median septum, which is largely buried in the valve floor posteriorly, and outer plates that are connected to the median septum via prismatic substance (with poorly developed lamellar layer at the junctions) at, or slightly above, the valve floor. These constitute criteria by which many species previously assigned to Parastrophinella are excluded from the genus. Late Ordovician species that fit the redefinition of Parastrophinella are now confined to eastern North America. The genus crosses the Ordovician/Silurian boundary without major morphologic change, and Early Silurian species of Parastrophinella occur in both eastern North America and Great Britain. In the Late Ordovician, the pentamerid fauna of North America (Laurentia) contrasted sharply with that of Baltica and Kazakhstan, where the Holorhynchus fauna was dominant. Typical elements of the Holorhynchus fauna, such as the large-shelled Holorhynchus and Proconchidium, are known only in the northern parts of Laurentia (Baffin Island, Greenland, and Kolyma), and are absent in the Hudson Bay and Williston basins and southwards. |
format |
Article in Journal/Newspaper |
author |
Jin, Jisuo Copper, Paul |
spellingShingle |
Jin, Jisuo Copper, Paul Parastrophinella (Brachiopoda): Its paleogeographic significance at the Ordovician/Silurian boundary |
author_facet |
Jin, Jisuo Copper, Paul |
author_sort |
Jin, Jisuo |
title |
Parastrophinella (Brachiopoda): Its paleogeographic significance at the Ordovician/Silurian boundary |
title_short |
Parastrophinella (Brachiopoda): Its paleogeographic significance at the Ordovician/Silurian boundary |
title_full |
Parastrophinella (Brachiopoda): Its paleogeographic significance at the Ordovician/Silurian boundary |
title_fullStr |
Parastrophinella (Brachiopoda): Its paleogeographic significance at the Ordovician/Silurian boundary |
title_full_unstemmed |
Parastrophinella (Brachiopoda): Its paleogeographic significance at the Ordovician/Silurian boundary |
title_sort |
parastrophinella (brachiopoda): its paleogeographic significance at the ordovician/silurian boundary |
publisher |
Cambridge University Press (CUP) |
publishDate |
1997 |
url |
http://dx.doi.org/10.1017/s0022336000039391 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022336000039391 |
genre |
Baffin Island Baffin Greenland Hudson Bay |
genre_facet |
Baffin Island Baffin Greenland Hudson Bay |
op_source |
Journal of Paleontology volume 71, issue 3, page 369-380 ISSN 0022-3360 1937-2337 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0022336000039391 |
container_title |
Journal of Paleontology |
container_volume |
71 |
container_issue |
3 |
container_start_page |
369 |
op_container_end_page |
380 |
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1810433271703535616 |