Ordovician sponge spicules from Spitsbergen, Nevada and Newfoundland: new evidence for the Hexactinellida early differentiation
- Autores
- Carrera, Marcelo G.; Maletz, J.
- Año de publicación
- 2010
- Idioma
- inglés
- Tipo de recurso
- documento de conferencia
- Estado
- versión publicada
- Descripción
- Division of Hexactinellida into the subclasses Amphidiscophora and Hexasterophora is now generally accepted due to their very distinct types of microscleres, namely amphidiscs and hexasters, respectively. Microscleres of this type have been recognized in the Lower Paleozoic. We examined exceptionally well preserved spicule assemblages from three particular Lower to Middle Ordovician localities: Spitsb ergen (Floian-Dapingian), Nevada (Vinini Formation, Dapingian) and Newfoundland (Cow Head Formation, Tremadocian and Table Head Group, Darriwilian). The presence of hexaster-type spicules, hemidiscs and amphidiscs is reported here. The hexasters are certainly documented from the Lower Ordovician and possibly from the Cambrian. Although hemidiscs were reported from the Lower Ordovician, oldest true amphidiscs were reported from the Silurian. The occurrence of amphidiscs in these localities implies that the Amphidiscophora can be certainly traced back to the Lower Ordovician. The occurrence of five different types of scopules (typical microscleres of the Sceptrulophora) significantly increases the diversity of this group in the Ordovician. The collection also includes important and variable types of hexactinellid spicules (pinular hexactines and pentactines, equinate hexactines, tauactins and inflated pentactines, and different types of uncinate monactins), calcareous heteractines, and different types of demosponge spicules (oxiasters, C-shaped sigmata, trianes and dendroclones).
Sesiones libres
Facultad de Ciencias Naturales y Museo - Materia
-
Ciencias Naturales
Paleontología
Ordovician sponge spicules
Spitsbergen, Nevada
Newfoundland - Nivel de accesibilidad
- acceso abierto
- Condiciones de uso
- http://creativecommons.org/licenses/by-nc-sa/4.0/
- Repositorio
- Institución
- Universidad Nacional de La Plata
- OAI Identificador
- oai:sedici.unlp.edu.ar:10915/16830
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Ordovician sponge spicules from Spitsbergen, Nevada and Newfoundland: new evidence for the Hexactinellida early differentiationCarrera, Marcelo G.Maletz, J.Ciencias NaturalesPaleontologíaOrdovician sponge spiculesSpitsbergen, NevadaNewfoundlandDivision of Hexactinellida into the subclasses Amphidiscophora and Hexasterophora is now generally accepted due to their very distinct types of microscleres, namely amphidiscs and hexasters, respectively. Microscleres of this type have been recognized in the Lower Paleozoic. We examined exceptionally well preserved spicule assemblages from three particular Lower to Middle Ordovician localities: Spitsb ergen (Floian-Dapingian), Nevada (Vinini Formation, Dapingian) and Newfoundland (Cow Head Formation, Tremadocian and Table Head Group, Darriwilian). The presence of hexaster-type spicules, hemidiscs and amphidiscs is reported here. The hexasters are certainly documented from the Lower Ordovician and possibly from the Cambrian. Although hemidiscs were reported from the Lower Ordovician, oldest true amphidiscs were reported from the Silurian. The occurrence of amphidiscs in these localities implies that the Amphidiscophora can be certainly traced back to the Lower Ordovician. The occurrence of five different types of scopules (typical microscleres of the Sceptrulophora) significantly increases the diversity of this group in the Ordovician. The collection also includes important and variable types of hexactinellid spicules (pinular hexactines and pentactines, equinate hexactines, tauactins and inflated pentactines, and different types of uncinate monactins), calcareous heteractines, and different types of demosponge spicules (oxiasters, C-shaped sigmata, trianes and dendroclones).Sesiones libresFacultad de Ciencias Naturales y Museo2010info:eu-repo/semantics/conferenceObjectinfo:eu-repo/semantics/publishedVersionResumenhttp://purl.org/coar/resource_type/c_5794info:ar-repo/semantics/documentoDeConferenciaapplication/pdfhttp://sedici.unlp.edu.ar/handle/10915/16830enginfo:eu-repo/semantics/altIdentifier/isbn/978-987-95849-7-2info:eu-repo/semantics/reference/hdl/10915/25738info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by-nc-sa/4.0/Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-09-03T10:25:54Zoai:sedici.unlp.edu.ar:10915/16830Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-03 10:25:54.867SEDICI (UNLP) - Universidad Nacional de La Platafalse |
dc.title.none.fl_str_mv |
Ordovician sponge spicules from Spitsbergen, Nevada and Newfoundland: new evidence for the Hexactinellida early differentiation |
title |
Ordovician sponge spicules from Spitsbergen, Nevada and Newfoundland: new evidence for the Hexactinellida early differentiation |
spellingShingle |
Ordovician sponge spicules from Spitsbergen, Nevada and Newfoundland: new evidence for the Hexactinellida early differentiation Carrera, Marcelo G. Ciencias Naturales Paleontología Ordovician sponge spicules Spitsbergen, Nevada Newfoundland |
title_short |
Ordovician sponge spicules from Spitsbergen, Nevada and Newfoundland: new evidence for the Hexactinellida early differentiation |
title_full |
Ordovician sponge spicules from Spitsbergen, Nevada and Newfoundland: new evidence for the Hexactinellida early differentiation |
title_fullStr |
Ordovician sponge spicules from Spitsbergen, Nevada and Newfoundland: new evidence for the Hexactinellida early differentiation |
title_full_unstemmed |
Ordovician sponge spicules from Spitsbergen, Nevada and Newfoundland: new evidence for the Hexactinellida early differentiation |
title_sort |
Ordovician sponge spicules from Spitsbergen, Nevada and Newfoundland: new evidence for the Hexactinellida early differentiation |
dc.creator.none.fl_str_mv |
Carrera, Marcelo G. Maletz, J. |
author |
Carrera, Marcelo G. |
author_facet |
Carrera, Marcelo G. Maletz, J. |
author_role |
author |
author2 |
Maletz, J. |
author2_role |
author |
dc.subject.none.fl_str_mv |
Ciencias Naturales Paleontología Ordovician sponge spicules Spitsbergen, Nevada Newfoundland |
topic |
Ciencias Naturales Paleontología Ordovician sponge spicules Spitsbergen, Nevada Newfoundland |
dc.description.none.fl_txt_mv |
Division of Hexactinellida into the subclasses Amphidiscophora and Hexasterophora is now generally accepted due to their very distinct types of microscleres, namely amphidiscs and hexasters, respectively. Microscleres of this type have been recognized in the Lower Paleozoic. We examined exceptionally well preserved spicule assemblages from three particular Lower to Middle Ordovician localities: Spitsb ergen (Floian-Dapingian), Nevada (Vinini Formation, Dapingian) and Newfoundland (Cow Head Formation, Tremadocian and Table Head Group, Darriwilian). The presence of hexaster-type spicules, hemidiscs and amphidiscs is reported here. The hexasters are certainly documented from the Lower Ordovician and possibly from the Cambrian. Although hemidiscs were reported from the Lower Ordovician, oldest true amphidiscs were reported from the Silurian. The occurrence of amphidiscs in these localities implies that the Amphidiscophora can be certainly traced back to the Lower Ordovician. The occurrence of five different types of scopules (typical microscleres of the Sceptrulophora) significantly increases the diversity of this group in the Ordovician. The collection also includes important and variable types of hexactinellid spicules (pinular hexactines and pentactines, equinate hexactines, tauactins and inflated pentactines, and different types of uncinate monactins), calcareous heteractines, and different types of demosponge spicules (oxiasters, C-shaped sigmata, trianes and dendroclones). Sesiones libres Facultad de Ciencias Naturales y Museo |
description |
Division of Hexactinellida into the subclasses Amphidiscophora and Hexasterophora is now generally accepted due to their very distinct types of microscleres, namely amphidiscs and hexasters, respectively. Microscleres of this type have been recognized in the Lower Paleozoic. We examined exceptionally well preserved spicule assemblages from three particular Lower to Middle Ordovician localities: Spitsb ergen (Floian-Dapingian), Nevada (Vinini Formation, Dapingian) and Newfoundland (Cow Head Formation, Tremadocian and Table Head Group, Darriwilian). The presence of hexaster-type spicules, hemidiscs and amphidiscs is reported here. The hexasters are certainly documented from the Lower Ordovician and possibly from the Cambrian. Although hemidiscs were reported from the Lower Ordovician, oldest true amphidiscs were reported from the Silurian. The occurrence of amphidiscs in these localities implies that the Amphidiscophora can be certainly traced back to the Lower Ordovician. The occurrence of five different types of scopules (typical microscleres of the Sceptrulophora) significantly increases the diversity of this group in the Ordovician. The collection also includes important and variable types of hexactinellid spicules (pinular hexactines and pentactines, equinate hexactines, tauactins and inflated pentactines, and different types of uncinate monactins), calcareous heteractines, and different types of demosponge spicules (oxiasters, C-shaped sigmata, trianes and dendroclones). |
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2010 |
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2010 |
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eng |
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