Siphonotretoid brachiopods – a thorny problem
Siphonotretoids are presently placed within the subphylum Linguliformea and the class Lingulata, where they constitute a small, relatively short-lived superfamily and order, appearing near the end of the mid-Cambrian, with most forms becoming extinct near the end of the Late Ordovician, but with som...
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| Format: | Article |
| Language: | English |
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Estonian Academy Publishers
2023-06-01
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| Series: | Estonian Journal of Earth Sciences |
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| Online Access: | https://kirj.ee/wp-content/plugins/kirj/pub/earth-1-2023-132_20230608205307.pdf |
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| author | Lars E. Holmer Leonid E. Popov Mansoureh Ghobadi Pour Yue Liang Zhifei Zhang |
| author_facet | Lars E. Holmer Leonid E. Popov Mansoureh Ghobadi Pour Yue Liang Zhifei Zhang |
| author_sort | Lars E. Holmer |
| collection | DOAJ |
| description | Siphonotretoids are presently placed within the subphylum Linguliformea and the class Lingulata, where they constitute a small, relatively short-lived superfamily and order, appearing near the end of the mid-Cambrian, with most forms becoming extinct near the end of the Late Ordovician, but with some rare forms ranging through the Silurian and even into the early Devonian. It has been noted previously that siphonotretides are very different from all other lingulates in shell structure, ontogeny and ornamentation, and may have diverged from other lingulates already during the early Cambrian. Findings of exceptionally preserved âsoft-shelledâ possible early stem-group setigerous representatives such as Acanthotretella in the Burgess Shale and the Chengjiang fauna have strengthened this view. Exceptionally preserved siphonotretides from Iran clearly show that they are provided with organic setal structures associated with spines, and similar setal structures are known from stem brachiopods, such as Micrina and Mickwitzia, as well as from some later true rhynchonelliforms. Evidence for preserved setal structures is now also recorded from the CambrianâOrdovician boundary beds in Wyoming. In the Ordovician, the spinous structures include complex branching forms, such as the widely distributed Alichovia, and Siphonotreta itself has clear evidence of branching spines. The branching spines probably also contained setal structures, and similar forked setae are known from living annelids. |
| first_indexed | 2024-03-13T05:35:30Z |
| format | Article |
| id | doaj.art-6dc74ed57b0c40719d4a9217c533a9af |
| institution | Directory Open Access Journal |
| issn | 1736-4728 1736-7557 |
| language | English |
| last_indexed | 2024-03-13T05:35:30Z |
| publishDate | 2023-06-01 |
| publisher | Estonian Academy Publishers |
| record_format | Article |
| series | Estonian Journal of Earth Sciences |
| spelling | doaj.art-6dc74ed57b0c40719d4a9217c533a9af2023-06-14T07:33:30ZengEstonian Academy PublishersEstonian Journal of Earth Sciences1736-47281736-75572023-06-017211320https://doi.org/10.3176/earth.2023.02https://doi.org/10.3176/earth.2023.02Siphonotretoid brachiopods – a thorny problemLars E. Holmer0Leonid E. Popov1Mansoureh Ghobadi Pour2Yue Liang3Zhifei Zhang4State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life & Environments, Department of Geology, Northwest University, Xi’an, 710069 China; Institute of Earth Sciences, Palaeobiology, Uppsala University, SE-752 36 Uppsala, SwedenDepartment of Geology, National Museum of Wales, Cathays Park, Cardiff CF10 3NP, United Kingdom; leonid.popov@museumwales.ac.ukDepartment of Geology, Faculty of Sciences, Golestan University, Gorgan 49138-15739, Iran; mghobadipour@yahoo.co.uk, m.ghobadipour@gu.ac.ir; / Department of Geology, National Museum of Wales, Cathays Park, Cardiff CF10 3NP, United KingdomState Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life & Environments, Department of Geology, Northwest University, Xi’an, 710069 China; Institute of Earth Sciences, Palaeobiology, Uppsala University, SE-752 36 Uppsala, Sweden; State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environments, Department of Geology, Northwest University, Xi’an 710069, ChinaState Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life & Environments, Department of Geology, Northwest University, Xi’an, 710069 ChinaSiphonotretoids are presently placed within the subphylum Linguliformea and the class Lingulata, where they constitute a small, relatively short-lived superfamily and order, appearing near the end of the mid-Cambrian, with most forms becoming extinct near the end of the Late Ordovician, but with some rare forms ranging through the Silurian and even into the early Devonian. It has been noted previously that siphonotretides are very different from all other lingulates in shell structure, ontogeny and ornamentation, and may have diverged from other lingulates already during the early Cambrian. Findings of exceptionally preserved âsoft-shelledâ possible early stem-group setigerous representatives such as Acanthotretella in the Burgess Shale and the Chengjiang fauna have strengthened this view. Exceptionally preserved siphonotretides from Iran clearly show that they are provided with organic setal structures associated with spines, and similar setal structures are known from stem brachiopods, such as Micrina and Mickwitzia, as well as from some later true rhynchonelliforms. Evidence for preserved setal structures is now also recorded from the CambrianâOrdovician boundary beds in Wyoming. In the Ordovician, the spinous structures include complex branching forms, such as the widely distributed Alichovia, and Siphonotreta itself has clear evidence of branching spines. The branching spines probably also contained setal structures, and similar forked setae are known from living annelids.https://kirj.ee/wp-content/plugins/kirj/pub/earth-1-2023-132_20230608205307.pdflower palaeozoicbrachiopodslingulatessiphonotretides |
| spellingShingle | Lars E. Holmer Leonid E. Popov Mansoureh Ghobadi Pour Yue Liang Zhifei Zhang Siphonotretoid brachiopods – a thorny problem Estonian Journal of Earth Sciences lower palaeozoic brachiopods lingulates siphonotretides |
| title | Siphonotretoid brachiopods – a thorny problem |
| title_full | Siphonotretoid brachiopods – a thorny problem |
| title_fullStr | Siphonotretoid brachiopods – a thorny problem |
| title_full_unstemmed | Siphonotretoid brachiopods – a thorny problem |
| title_short | Siphonotretoid brachiopods – a thorny problem |
| title_sort | siphonotretoid brachiopods a thorny problem |
| topic | lower palaeozoic brachiopods lingulates siphonotretides |
| url | https://kirj.ee/wp-content/plugins/kirj/pub/earth-1-2023-132_20230608205307.pdf |
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