Retiolitine graptolites from the Aeronian and lower Telychian (Llandovery, Silurian) of Arctic Canada
An exceptional fauna of retiolitine graptolites from Aeronian and lowermost Telychian strata in Arctic Canada provides significant new insights into the phylogeny and history of diversity of retiolitine graptolites. All specimens were isolated by dissolution of calcite concretions. The results indic...
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ftbioone:10.1017/jpa.2016.107 2024-06-02T08:01:30+00:00 Retiolitine graptolites from the Aeronian and lower Telychian (Llandovery, Silurian) of Arctic Canada Michael J. Melchin Alfred C. Lenz Anna Kozłowska Michael J. Melchin Alfred C. Lenz Anna Kozłowska world 2017-01-01 text/HTML https://doi.org/10.1017/jpa.2016.107 en eng The Paleontological Society doi:10.1017/jpa.2016.107 All rights reserved. https://doi.org/10.1017/jpa.2016.107 Text 2017 ftbioone https://doi.org/10.1017/jpa.2016.107 2024-05-07T00:47:45Z An exceptional fauna of retiolitine graptolites from Aeronian and lowermost Telychian strata in Arctic Canada provides significant new insights into the phylogeny and history of diversity of retiolitine graptolites. All specimens were isolated by dissolution of calcite concretions. The results indicate that retiolitines emerged within the lower Aeronian and reached a higher than expected level of diversity and disparity of forms by mid-Aeronian time. The uppermost Aeronian is almost totally devoid of preserved graptolites in Arctic Canada and, therefore, our material provides few new insights into retiolitine morphology or diversity through that interval. Specimens assigned to Pseudoretiolites? sp. occur in well-dated lower Aeronian strata, thus representing the lowest known biostratigraphic occurrences of retiolitines globally. This taxon appears to be morphologically primitive in that the sicula is completely preserved, with preservation of the proximal regions of theca 11, as well as distal thecal fusellum on mature specimens. Cladistic analysis of the Llandovery retiolitines shows that Pseudoretiolites is a stem genus for all of the other retiolitine taxa, which comprise two clades: one consisting of Pseudoplegmatograptus, Retiolites, and Stomatograptus and their derivatives; and the other includes Rotaretiolites, Aeroretiolites, Aeroretiolites?, Eorograptus, Paraplectograptus, Paraplectograptus?, and Sokolovograptus, and all of those other taxa that had previously been placed in the Plectograptinae. We follow the recent proposal that all of the taxa traditionally assigned to the Retiolitidae be assigned to the subfamily Retiolitinae. The following new taxa are described: Pseudoretiolites hyrichus n. sp., Eorograptus spirifer n. sp., and Aeroretiolites cancellatus n. gen. n. sp. Text Arctic BioOne Online Journals Arctic Canada Journal of Paleontology 91 1 116 145 |
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language |
English |
description |
An exceptional fauna of retiolitine graptolites from Aeronian and lowermost Telychian strata in Arctic Canada provides significant new insights into the phylogeny and history of diversity of retiolitine graptolites. All specimens were isolated by dissolution of calcite concretions. The results indicate that retiolitines emerged within the lower Aeronian and reached a higher than expected level of diversity and disparity of forms by mid-Aeronian time. The uppermost Aeronian is almost totally devoid of preserved graptolites in Arctic Canada and, therefore, our material provides few new insights into retiolitine morphology or diversity through that interval. Specimens assigned to Pseudoretiolites? sp. occur in well-dated lower Aeronian strata, thus representing the lowest known biostratigraphic occurrences of retiolitines globally. This taxon appears to be morphologically primitive in that the sicula is completely preserved, with preservation of the proximal regions of theca 11, as well as distal thecal fusellum on mature specimens. Cladistic analysis of the Llandovery retiolitines shows that Pseudoretiolites is a stem genus for all of the other retiolitine taxa, which comprise two clades: one consisting of Pseudoplegmatograptus, Retiolites, and Stomatograptus and their derivatives; and the other includes Rotaretiolites, Aeroretiolites, Aeroretiolites?, Eorograptus, Paraplectograptus, Paraplectograptus?, and Sokolovograptus, and all of those other taxa that had previously been placed in the Plectograptinae. We follow the recent proposal that all of the taxa traditionally assigned to the Retiolitidae be assigned to the subfamily Retiolitinae. The following new taxa are described: Pseudoretiolites hyrichus n. sp., Eorograptus spirifer n. sp., and Aeroretiolites cancellatus n. gen. n. sp. |
author2 |
Michael J. Melchin Alfred C. Lenz Anna Kozłowska |
format |
Text |
author |
Michael J. Melchin Alfred C. Lenz Anna Kozłowska |
spellingShingle |
Michael J. Melchin Alfred C. Lenz Anna Kozłowska Retiolitine graptolites from the Aeronian and lower Telychian (Llandovery, Silurian) of Arctic Canada |
author_facet |
Michael J. Melchin Alfred C. Lenz Anna Kozłowska |
author_sort |
Michael J. Melchin |
title |
Retiolitine graptolites from the Aeronian and lower Telychian (Llandovery, Silurian) of Arctic Canada |
title_short |
Retiolitine graptolites from the Aeronian and lower Telychian (Llandovery, Silurian) of Arctic Canada |
title_full |
Retiolitine graptolites from the Aeronian and lower Telychian (Llandovery, Silurian) of Arctic Canada |
title_fullStr |
Retiolitine graptolites from the Aeronian and lower Telychian (Llandovery, Silurian) of Arctic Canada |
title_full_unstemmed |
Retiolitine graptolites from the Aeronian and lower Telychian (Llandovery, Silurian) of Arctic Canada |
title_sort |
retiolitine graptolites from the aeronian and lower telychian (llandovery, silurian) of arctic canada |
publisher |
The Paleontological Society |
publishDate |
2017 |
url |
https://doi.org/10.1017/jpa.2016.107 |
op_coverage |
world |
geographic |
Arctic Canada |
geographic_facet |
Arctic Canada |
genre |
Arctic |
genre_facet |
Arctic |
op_source |
https://doi.org/10.1017/jpa.2016.107 |
op_relation |
doi:10.1017/jpa.2016.107 |
op_rights |
All rights reserved. |
op_doi |
https://doi.org/10.1017/jpa.2016.107 |
container_title |
Journal of Paleontology |
container_volume |
91 |
container_issue |
1 |
container_start_page |
116 |
op_container_end_page |
145 |
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1800745878724542464 |